Do you think a neighbouring cut affects a cut? It seemed like the first cut had the full solid support of a solid board, whereas after the first cut, the board had less support to the cut, possibly causing more vibration, which might mean not a fair comparison across cuts due to uneven conditions for the cuts. Maybe try the same experiment but start with a different cut first and see what you get. Or have a large separation , maybe even seperate boards... You have lots of boards to spare right? 😁
Way back when taking wood shop in Jr. high, our instructor taught us the projection should be the thickness of the saw blade. As most blades were about 1/8" thick back then, it would hold true to your results.
I suspect that that rule really has nothing to do with the physics of the cut depth vs. blade width, rather it's more memorable than saying "1/8th inch" and should be good enough regardless of the actual blade width.
I was tought to have the the teeth just sticking past. Your teeth cut more latterally at that depth and at full depth you are cutting vertically which causes the rough cut.
Consider the geometry of the cut. When cutting at minimal depth, only a small cross section of the blade is engaged at a time, and the kerf will have a gradual slope at the front following the blade curve. That means the angle at which the teeth engage the material is shallow, with the teeth cutting more forward than upward. On the other hand, at full depth a larger section of blade is engaged, the end of the kerf is nearly vertical, and the teeth engage in an almost entirely upward direction. From the geometry alone, it's clear that greater depth will result in more upward force which would result in more tear out. Additionally, the lower depth cut with its low angle of attack should mean the teeth spend more time engaged and the next tooth should enter the cut before the previous tooth leaves it which should reduce the chance of a tooth getting caught causing kickback or additional tear out. The disadvantage though, is that when you make an incomplete cut you have a really long ramp out of the kerf, where a deep cut can get closer to flush.
The lenght of the blade in the cut will influence ability to cut straight in a free hand cut, also the center of gravity of the saw is lower to workpiece when cutting full depth. The position of the handle of saw will make a difference, on some saw the angle becomes less comfortable when raising motor away from work piece. This is an advantage of drop foot saws where angle does not change and also location of blade is same when making angled and perpendicular cuts.
100% agree.. I can tell that you actually work with circ saws 🫡 I run full depth unless it’s finish material I don’t want to chip, then I keep it shallow.
@@SLPbuilders 100% agree as well. Full depth, at least with my saws, just gives me a more stable feel of control and makes for a more precise, straight cut. I don't cut 'finish' work with a dull blade anyway - not sure why anyone would. When I do worry about tear-out, I'll cut finish-side down or use Frog tape. With the finish-side on the bottom, the teeth of the blade cut while entering the piece and don't cause tear-out on that side, even if they do on the 'rough' side.
I admire your effort and intent, but there's a reason your first and last cuts look clean. The cuts you made in your tests are too close together - the wood is waggling while your blade goes through it - if you got a shot of an end-on view and had slow motion, you'd see the sliver of wood you're cutting near jumping up and down, likely causing the tearouts you're seeing in the middle.
What order did you make your cuts? Those resulting wooden fingers are unsupported. That could allow part of each subsequent cut to flex and could partly account for some of the differences.
That’s a great point. I filmed all of the cuts so I just double checked and I cut all of them from shallowest to deepest so it’s probably worth trying some new tests in the opposite order as well as making the cuts further apart (no fingers) or supported just to test that out. Great point that I should have caught! I don’t suspect it will have much of an impact on the outcome but I could absolutely be wrong about that. Thanks for the insight.
I saw a video showing how to get clean cuts by doing two passes, first only a few mm deep, second cut through the remainder of the board. Seems to work well if you need a clean cut?
My late brother was a wood machinist for about 50 years and always said saw teeth should just clear under the board being cut. I don't use a power saw very often, so I follow his advise and keep the blade about 1/8 inch. 🐯
I was taught in my Wood Technics course in trade school that just past the bottom (or about 1/8") is best. The reasons given is that puts the most teeth in the cut and for safety.
All of the blades you purchased are thin kerf blades. Blades use to have both clearance at the sides and set the teeth angled away from the kerf. No longer the case. At 2:18 that is BECAUSE the blade is shallow. Blades have usually two features to consider. One is pull down or hold down. Some blade protruding below the work tends to suck the saw down toward the work. And side clearance. Lack of side clearance creates heat and friction. Blades used to have set. They, with few exceptions,, no longer have set,, the lack of clearance makes them prone to side friction,, from accumulation of sticky tars from the materials being cut or the heating of the blade causing it to warp. Thin blades are there to make more money for the manufacturers.. Ain't no other reason. Your test. A perfectly sharp brand new blade 8 teeth or 60 teeth it will give a nice smooth cut. Hand circular saw tests should be with a used blade,, your file dulled the file against the carbide and the blade is still perfectly clean. Every blade I have or have thrown away the sides of the blade or the sides of the carbides are covered with brown smootch. The least friction on a blade is when the blade protrudes past the work by about 1/2 to 3/4 of an inch. The blade is doing its cutting on the upstroke on a limited cutting face. And deeper is not good because more of the dangerous blade is sticking out and the deeper blade can have vastly more friction and heat. Table saws same principles. 1/2 to 3/4 of and inch so the blade is sucking the work down against the table,, shallow it is trying to throw it,, too much sticking out a danger to hands and fingers and greatly increases the friction and heat. Objections,, no smootch on the sides of the teeth or blade,, and the way a hand circular is used is an 8 foot rip to a chalk line.
@@Sailor376also modern blades have carbide bits which are generally thicker than the disc providing the clearance that set used to. The blades published kerf is greater than the disc gauge. Thin kerf blades have less clearance.
I was taught to reduce the depth to the minimum required to make the cut, mostly for safety reasons. The 'full-depth theory', however, was once explained to me as being safer because the blade, despite the turning force, would be acting on the material in a more vertical action, rather than horizontal, thereby mitigated kickback. I've never been convinced, and I've always stuck to what I was taught. As for quality of cut, well, this video is very helpful! 🙏🏽
The less the stick-out the more teeth in the cut, and each tooth takes a smaller bite, less work for each tooth, less force needed to push, and usually a smoother cut. NB, that works as long as you can keep the saw from lifting and the cut straight. If those are a problem, deepen the stick-out. Works for table saws, too. Don't plunge straight down, put the front of the foot on the piece, aligned with the cut and gradually lower the blade into the cut.
Hard to judge because cut quality is too dependent on feed rate/force and keeping the saw straight. Both can make good cuts if youre careful. A shallow blade at the same rate is taking a shallower but longer bite. Full depth is more dangerous for exposed blade, but less dangerous for kickback when the wood pinches. I use both methods depending on what I'm working on.
Just curious how did you make the same force for each cut? It's amazing to me how you can clean up a cut by going slower. How did you make sure you were going at the same speed?
Suggest you do some test cutting using "painters tape" on plywood to see if it minimizes tear out... Ive seen videos of woodworkers doing this and wonder if it does eliminate/reduce tearout particularly in cabinet grades of plywood.
Thanks for this. As some mentioned there was some lack of control in the testing, but guess what… there is no control when the average homeowner makes a cut an either. I wonder if the saw tips more side to side when the blade is deep. But doesn’t matter here…. Results for how folks typically use a circular saw are useful.
You are correct. Setting the depth to the bottom of the tooth profile (the gullet as you said) allows for proper removal of dust/debris while cutting. I went to college for woodworking and this is what they taught.
@@joshuawiedenbeck6944I don’t understand that theory. Sure, the debris can’t be cleared until the gullet is exposed, but it’s only completely covered for a fraction of a second at the front edge of the cut. You have nearly the entire rotation of the blade for debris to fall out.
@@StolenJoker84 There are a lot of other reasons as well (like balancing safety with needing the teeth to provide downward pressure on the material), I just commented with one of the more important aspects. Heat dispersion is another....
@@joshuawiedenbeck6944 For head dispersion, don’t you also have the entire rotation of the blade? You also have the thermal mass of the blade as well. As far as “downward pressure” … aren’t you putting downward pressure on the piece when you’re holding the saw, and you still have the down force from the rotation of the rear edge of the blade. (although, I acknowledge that this may not apply to table saws) Don’t get me wrong, I am not trying to argue anything, and am just trying to have conversation and understand the theory.
@StolenJoker84 The downward pressure has to be greater than the upward pressure on the back end of the blade. If the blade is too shallow, the blade can actually force the piece upward. For heat dispersion, if the wood is trapped in the gullets at the time of the cut, there is a chance the sawdust will get packed into the gullets and will have a harder time to eject. The increased heat also compounds. And as soon as heat gets to the point of burning, the blade loses sharpness extremely quickly. It's a calculation that CNC operators have to take into account when they run their machines. Chip/saw dust size affects heat dispersion drastically.
When cutting the plywood, the fibers of the veneer were being pushed by the dull blade, instead of being severed by a sharp blade. That's why there was massive tearout. The veneer is so thin that, when the spinning blade exits the top of the plywood (as it cuts on the up-stroke), the blunt edge of the blade pushes that layer up, and the glue fails, causing the layer of plywood to tear away, wherever the grain to glue bond is weakest. I bet nobody has ever tried this, and I should probably make my own video to demonstrate it, but I'm hoping you'll read this, and make a video, because the physics behind it makes me think it will work as I imagine it. Place your saw at the end of the sheet of material, so you can set the saw blade depth. Set it up so that the blade protrudes from the bottom of the saw plate, just deep enough so that it will cut all the way through the material. Then rotate the blade by hand to put the tooth at the front edge aligned with the position it will be when it exits the top layer of veneer, one its way up, as it cuts. Now, adjust the depth of the blade to get that tooth so that it exits the top layer at a 45 degree angle (45 degrees pointing away from the saw, towards the direction of the line to be cut) as it exits the wood on the way up. That will create a shearing action as it exits. If you think about it, if you set it up so that the angle of the tooth is the other way, the tip of the tooth will hit the top edge of veneer as it exits, effectively slapping that top layer from the back, instead of shearing the wood. Again, I'm betting nobody else has ever thought of this, because I've never heard it explained this way - but it just came to me, and it makes sense, as the definition of cutting wood should be to sever the fibers as cleanly as you are able - and my use of hand tools, including very sharp chisels and hand planes (sharpened to 16000 grit, on a Shapton stone) has proven what really cleanly severed wood looks and feels like. I'm sure this post will get buried - but it would be fun to see a video. And if nobody makes one, maybe I'll do it myself, one of these days ... I'm going to subscribe because I'm going to hope that you read this post and try this, and make a video.
I learned how to use a skill saw on Ryobi battery saw. I learned really quickly to extend the end of the blade no more then 1/2 the with of the blade. It just worked better for that under powered saw.
excellent video my dude! I never gave much thought to cutting depth before now but have usually always stuck to about 1/8th inch simply cause it seems like the safest way to do it. its really nice to see that it also gives the best cut. 10/10 great video!
Nice simple test and all the results next to each other. Also shows that a guide fir the saw is needed where possible as there is a clear sign of blade cut wander with just the slightest movement of the saw. And. Cut veneers upside down with a guide.
I always set for a maximum depth of half the gullet and a minimum of about 1mm or 1/16” below…within this range I don’t measure it. Works for me at least on sheet goods. I suspect the full gullet used, to clear the chips, is more pertinent to thick boards where the blade is scooping waste out of a two inch tall kerf.
Here is my answer before watching. Half the tooth cutting depth. Never past the gullet. If you can run a circular saw freehand perfectly straight, sure and go full depth. The cutting edge kerf is wider than the supporting blade. However, add in any factors such as, you’re a mere mortal and don’t always make a perfect cut. Support of the cut underneath or the lack there of. Or even variations in material thickness. All that can make contact with the blade stock. Not a problem if it’s only the teeth in the cut. If you use the least amount blade necessary, the saw is using all of its energy into the cut. And finally, you are getting more teeth doing the cutting work at the same time over a longer time vs a few teeth hitting in the front for short moments chipping out the wood. This is also easier on the blade.
On your demo I was thinking “chatter” (others call vibration) from the cuts being so close together (lack of support). I’m no great sawyer but I’ve found over the years that about a “thumb” or 1 inch projection works best overall for cleanliness and control. I’m no “scientist” just my observation over thousands of cuts.
There is one thing you DON"T mention i n this video, and I have never heard mentioned in any video, but have proven to myself and my co-workers time and again. If you set the depth shallower (i.e. 1/8th to 1/4 inch through) the lower blade guard works WAY better, and is less likely to make the cut go off line as you enter the board. Just a personal observation I wanted to share.
I worked in a machine shop that had burned down a few years before and lost their plate saw. Turns out, you can cut plate aluminum with skilsaws just fine. We did all the way up to 6 1/2. The blades all have carbide teeth now anyway, so you don't even have to worry about overheating. The thing about carbite that they taught me is thay it doesn't like interupted cuts. It doesn't like inadequate cooling either, either drench it or leave it dry. So what I did - which worked out pretty well - was set it to just barely make it through. This kept the teeth partly in the material, so not an interrupted cut. It also reduced the amount of the blade that was in the material, which reduced drag (pretty big deal on thick stuff) and made pinches less catastrophic. My experience on wood as it concerns cut quality has been that it has more to do with the chip load you run the saw at than anything else. You push it hard and it'll cut fast and make a mess. Real slow and it looks great. Beyond that I never really cared. I'm not a carpenter
I cut Aluminum plate with hand held circular saw as far back as 1984, always keep blade wetish with WD40 ( about all it is good for) to help with reweld ( Aluminum sticking to the carbide). Same process on a table saw.
This is why you need special guards and tools when going full depth. It is only recommended on a heavy table saw as it's absurdly prone to accidents and the mass of the table is all that's keeping it together. Even when using a table saw in a wood shop, we set it to barely poking out above the surface unless the material required it. Some things simply don't cut well except very slotly at nearly 90 degrees. Yes, kickback is a real factor if it happens and it rarely ends well. Seeing a piece of wood shoot 20 ft across the shop brings home safety real quick.
Add a sacrificial piece of board on the bottom and make sure the depth of cut not to exceed 1/4 of the bottom piece. Also added tape to the blade kerf on the board will help with the tear out (but who has time for that?).
For the cleanest, make the cut in two passes: one to a depth of 1/8" (only scoring the face of the board facing the sole of the saw), then a second one to whatever depth you want. Also, missing from the material list: particle board (not MDF) with a melamine surface - that's the most unforgiving when it comes to the quality of the cut (the particles are just waiting to explosively leave the material taking a bit of melamine with them).
Good to see the safest depth gives the best results. Makes sense too, the smallest exit angle would produce more shear and slicing than a blade 90 deg to the workpiece. Thanks for doing this!
`Something I discovered around thirty years when making furniture pieces using a circular saw (before finally buying a bench saw) was blade wobble. Didn't matter how deep or shallow the blade was set, my fairly new 9, 1/4 circular still had slight play in the shaft bearing which resulted in tear-out on the back side of the blade. Circular saws are certainly better now but I'd struggle to believe they can compare to a bench saw doing the same thing.
One thing I thought you would be testing is how much force/effort it would take to push a blade through the board; how easy is to to cut at various depths.
I think what's not mentioned here is blade angle. I noticed on a few circular saws I have (good brands) that the front of the saw cutting edge is at a very slight parallel angle compared to the rear cutting edge. (not the bevel angle) I believe this angle, even millimeters, can affect how clean the cut is. Something to look into. There is no way usually to adjust for this angle, as it's factory set most of the time, but it exists.
This is a second comment - because my other comment was already very long (but worth reading) ... My thought on why the full depth cut gave a messy cut on both sides; the blade isn't supported by the wood as it cuts - the entire blade is spinning freely below the wood being cut, and that blade can vibrate a lot, since there is nothing keeping the blade stable, as there is when the majority of the teeth are between the wood fibers as it cuts.
In your previous video you showed methods for getting good quality (lowest tearout) cuts, but it doesn't seem like you used that here. It was also be nice to see this done on a table saw where your hand movements would have less effect on lateral blade movement.
Quick question. I know the blade should stick just a bit out of cutting material. What if I've got stair treads with nosing . Obviously the nosing drops down twice of size of the tread. How to set the blade depth when you've got 2 different sizes in one piece of wood?
I cut full depth unless I don't have the clearance. Reason is safety and control and I understand physics and leverage. Cutting at full dept puts the reaction force exerted through the blade closer to the center line of the saw and it puts less force pushing the saw back and more force into pulling the saw directly down making kick back less of a chance.
I've been using my saw for regular projects around the house for years. I finally realized I should replace the blade so I went to RUclips for information and found this amazing video. Thank You!
At 3:45 mark you introduce the only thing that is important: the cutting angle. At 1/8", it is minimal, while at full depth it is the closest to being perpendicular to the board. Now decide for yourself if you want the saw blade teeth to attack your board almost tangentially (probably not good for the far end of the piece you cut), or you want them to fly across the board (bad expectation for plywood, as you can imagine).
When using a stamped steel shoe, like on a Ryobi, you don't have too much choice but to use full depth. The flexing of the shoe is more of a problem than the blade. If the blade spins too slow, the ply will force it off the cut line. Even with a guide.
That's always been my go to depth...the minimum protrusion that still gives you a clean cut. You'd think this would be fairly obvious; I mean that's how I arrived at it. But logical, and what people talk themselves into are rarely the same things. Good test. Thanks
I think a lot of people use a bigger depth than they need when they're working on a project where they're cutting multiple thicknesses of wood. Being lazy so that they don't have to keep resetting the depth. I've been guilty of this myself but this is definitely been an eye-opener.
Smallest depth/height will make clean cuts, with small and minimal burrs. Greatest depth/height will have more power, will cut faster and push the board/timber/etc down or towards the sole of the saw.
If you need this test to tell you full depth is the worst for tear then you haven’t used a saw much ….but good idea to try and test the depths even if the method might be flawed
The other problem with "F" is the saw has to be held 𝒑𝒆𝒓𝒇𝒆𝒄𝒕𝒍𝒚 straight and true inline with the intended cut direction. The less deep you cut, the less a wobble in your grip will effect the outcome.
In following a line down an 8' sheet of plywood, not using a straight edge or track, it's not about how many teeth are engaged that keeps it straight, but how much of the full diameter of the blade is engaged. Using the smallest cross section of the diameter, the easier it is to turn, so yes, less chance of kickback. With more diameter engaged, the harder it is to turn out of its kerf, and the saw will almost track itself, and holding steady, you will get the straightest cut. Sometimes "clean" is not defined by a lack of tear out, but by how straight a freehand cut is. Face down will usually come out clean either way. If I need to cut face up and it needs to be perfectly clean, say cutting laminate countertops, I will put masking tape down. If you're cutting a large beam that is beyond the depth of the saw, where you have to rotate the beam once or twice to get all the way through, at full depth you can feel the saw track in it's own kerf. So, of course, safety and proper setup is priority either way, but blade depth is always determined by application.
To me, the depth of cut really only matters according to the situation. If I'm just cutting wood on a set of saw horses I'll just let the blade cut all the way down. On the other hand, if I'm cutting into a floor to replace a bad section then I'll limit my depth to just over the thickness of the floor so I don't also cut halfway through the joists, lol.
I found the cleaner cuts come from about a quarter of a inch but that might differ between rpm of the saw mine cuts at 3500 rpm I think it's the cheap brushed Milwaukee
Consistency is the was to get the cleanest cut and using the right tool or method. If tearout don't matter I freehand, if consistent size matter I would use a guild. If you need to limit tearout use a new 40 tooth. Fewer teeth makes faster cuts and better on harder materials. I tend to use 3 saw teeth sizes: 24 and 40 for 7 1/4 saws while 40 to 60 on 10inch blades. If you need perfection use a router.
Something not covered is blade flex. Deeper the blade the more flex there will be and more blade wander, especially with a dull blade. It was pretty evident in some of the full depth cuts shown. The full depth kerf was wider and not straight. Been an 1/8” guy for nearly 4 decades and looks like I’ll continue cutting at that depth.
Who thought full depth was a good idea? I learned in grade school wood working class you only expose as much of the blade through as needed to cut the wood and ensure sawdust is expelled. One issue that wasn't touched on with the full blade is that it can also lead to a blade getting stuck in seizing in a cut if doing some cuts that aren't flat.
I think using a table saw might get even more accurate results narrowing the margin of error created by the human factor and have better test results on just the blade and machine. Kinda like sighting in a rifle standing vs using weighted sled and support stand.
Yes, a rip blade will cut plywood just fine, but a plywood blade will cut faster and last longer between sharpenings. I, however, no longer use plywood blades; I just use an 80tooth carbide-tooth blade for everything except long rips. (Most of my saws are 10".)
The difference is cuts is very subtle IMHO. My concern is dulling the blade. I want the longest blade life, because $$$. (I could be wrong but… ) It seems to me that the blade stays sharper LONGER, the less time it has to make contact with the wood. The shallower the depth the LONGER time the blade has to be IN the wood. Also, I would expect that the temperature and therefore blade heating, and the increase opportunity to burn the wood as well. So, those are two reasons that, I still think I’ll risk the “full depth” cut. Keep up the GW.
Nils Great minds think alike. The rule of thumb I have always used is half the distance of the tooth which is typically about an eighth of an inch or so. On my table saw I will sight the blades so that it just barely sticks up above the wood by half of a tooth.
Makes perfect sense, Jeff. I suspect if I did the same tests on a table saw the results would be about the same too. The half tooth makes sense and I have a very healthy fear of table saw injuries so I keep that blade as low as I can get away with.
Try to angle the teeth at 30-45 degrees to the top surface of the material, a 90 degree tooth that is perpendicular to the surface of the wood has the most surface area to slam into/ tear up through the fibres rather than cut them.
Here is one for you the teeth do the cutting the gullets help to clear the sawdust from the cat / kerf. Dropping the blade 3 inches farther than you need to just adds to the friction between the blade and the material you are cutting. Why the hell would you want the blade up by the arbore coming in contact with the material unless you have to while cutting the max depth of the saw
Nice video. I"m a beginner and i have a question: Is it useful or overkill to have 2 circular saws, one with a special blade for ripping and one with a special blade for crosscutting, because i don't like swapping blades, making the circular saw screw dull. I also have no table saw and i don't think i wil have one soon, because they are expensive. Hope to hear from you soon. Many thanks in advance
Two saws are good, but not just for ripping and cross cutting. If your saws are 7 1/4-in get a 24 tooth blade for ripping and cross cutting lumber. The second should be for plywood, and a 40 or 60 tooth blade is recommended.
If you think you will realize that on the shallow ones the blade is cutting more of the time than the deeper ones, as the deeper ones pass through the wood, whereas the shallow are staying in the wood.
Full depth on the blade should help with a straighter cut, due to the diameter of the blade acting as a straight edge. Plus, full depth lowers the centre of gravity of the saw, and makes the position of the handle more comfortable.
You may get a cleaner and safer cut with 1/8" but you have barely any side to side stability which makes long freehand cuts much harder to keep straight.
I noticed that all your cuts were on the same board. Could the vibration of the narrow wood contribute to more vibration in the board and thus messier cuts?
Someone else had mentioned that and I wonder the same thing. I'll try some additional cuts where they're way spaced out and see if there's any difference. I can then post the results in a pinned comment here.
Your 1/8 inch is cleanest because it’s your first cut… You then cut within 1/2 inch of your last cut causing a lot of vibration in the material between cuts. The tear out causing a worse looking cut is due to lack of support.
I was told when I was a child, plunge the blade just deep enough to show the entire tooth. Has always worked for me, cuts start getting ugly, replace the blade. More teeth, slower the cut, but better looking, looks don't matter, speed preferred, low teeth count. All pretty simple.
Its all about tear-out. The more perpendicular the blade teeth are to the work piece, the more tear-out. With more angle of the cutting edge or shallow the cut, the less tear-out.
Im the boss of no one. I can't agree with your safety assessment. The saw cuts and you lose parts no matter the depth. Plus there are other places othet than underneath to get into the blade. I find that a deeper depth helps me stay straight all the way down long cuts because a longer section of the blade is engaged; safer and a better cut. I also feel "kickback" of the saw and material is reduced because the contact areas of the blade with the material are more vertical, especially at the initial front cutting zone. There are also many times where blade depth is dictated by more than the ultimate cut quality. The thickness of the material, stuff that hits the motor like sleds and clamp down fences. I do this it was a good and worthwhile video, rhanks.
Please do not listen to this man. 35 years of experience says this is all wrong. Skill is required to make a straight cut. The saw blade cannot do it for you. Full depth cuts expose you to more chance of violent kickback. The back half of the blade is pushing the the saw up from the workpiece. If kickback begins, the saw lifts up, and is then pushed back by the bottom of the blade as it comes through the material. All in a fraction of a second. You want to limit the amount of blade exposed to the material. Maximum 1/4” of blade exposure. You get better results as well, as shown in this video. Please be safe.
Seems I've heard that a minimal blade height above your wood on a table saw is the setting for a clean cut. Seems the same would apply to a circular saw. 🤷♂️
Found an issue with your testing, At ~5 minutes you show a slow motion of the multiple cuts on the wood. You are putting the cuts too close to each other, the wood is flexing and bouncing back and forth...
It would actually work better at full depth if you were cutting metal. Granted, typically we cut metal with bandsaws, waterjets, laser cutters, or plasma cutters, but the less distance the cutting surface has to travel while engaged in the cut, the less heat and resistance it will have. That's why you really only typically see circular saws cutting bar stock in the world of metal working, as well as some other very specialized applications like slitting.
Do you think a neighbouring cut affects a cut? It seemed like the first cut had the full solid support of a solid board, whereas after the first cut, the board had less support to the cut, possibly causing more vibration, which might mean not a fair comparison across cuts due to uneven conditions for the cuts. Maybe try the same experiment but start with a different cut first and see what you get. Or have a large separation , maybe even seperate boards... You have lots of boards to spare right? 😁
Exactly what I was thinking!
I think the vibration from thin strips is a problem with the experiment
came here to say this, the experiment is scuffed. you can clearly see that each cut after the first is progressively worse.
The slow motion even showed the wood vibrating more and more as the number of cuts grew.
I thought the same, flawed test as the cut is not done under the same conditions.
Way back when taking wood shop in Jr. high, our instructor taught us the projection should be the thickness of the saw blade. As most blades were about 1/8" thick back then, it would hold true to your results.
I suspect that that rule really has nothing to do with the physics of the cut depth vs. blade width, rather it's more memorable than saying "1/8th inch" and should be good enough regardless of the actual blade width.
I was tought to have the the teeth just sticking past. Your teeth cut more latterally at that depth and at full depth you are cutting vertically which causes the rough cut.
Consider the geometry of the cut. When cutting at minimal depth, only a small cross section of the blade is engaged at a time, and the kerf will have a gradual slope at the front following the blade curve. That means the angle at which the teeth engage the material is shallow, with the teeth cutting more forward than upward. On the other hand, at full depth a larger section of blade is engaged, the end of the kerf is nearly vertical, and the teeth engage in an almost entirely upward direction. From the geometry alone, it's clear that greater depth will result in more upward force which would result in more tear out. Additionally, the lower depth cut with its low angle of attack should mean the teeth spend more time engaged and the next tooth should enter the cut before the previous tooth leaves it which should reduce the chance of a tooth getting caught causing kickback or additional tear out. The disadvantage though, is that when you make an incomplete cut you have a really long ramp out of the kerf, where a deep cut can get closer to flush.
This video is great. I have always set my blade depth at the minimum to get the cut done. Your video shows that is the way to go.
The lenght of the blade in the cut will influence ability to cut straight in a free hand cut, also the center of gravity of the saw is lower to workpiece when cutting full depth. The position of the handle of saw will make a difference, on some saw the angle becomes less comfortable when raising motor away from work piece. This is an advantage of drop foot saws where angle does not change and also location of blade is same when making angled and perpendicular cuts.
100% agree.. I can tell that you actually work with circ saws 🫡
I run full depth unless it’s finish material I don’t want to chip, then I keep it shallow.
@@SLPbuilders 100% agree as well. Full depth, at least with my saws, just gives me a more stable feel of control and makes for a more precise, straight cut. I don't cut 'finish' work with a dull blade anyway - not sure why anyone would. When I do worry about tear-out, I'll cut finish-side down or use Frog tape. With the finish-side on the bottom, the teeth of the blade cut while entering the piece and don't cause tear-out on that side, even if they do on the 'rough' side.
@@melmartinez7002 Exactly! When you know, you know. Unless you’re a keyboard warrior, then you always know 😂
^ real carpenter zone 👍👍
Fully agree, and I'm pretty sure I've never cared about the fuzz on the edge of an OSB cut.
I admire your effort and intent, but there's a reason your first and last cuts look clean. The cuts you made in your tests are too close together - the wood is waggling while your blade goes through it - if you got a shot of an end-on view and had slow motion, you'd see the sliver of wood you're cutting near jumping up and down, likely causing the tearouts you're seeing in the middle.
What order did you make your cuts? Those resulting wooden fingers are unsupported. That could allow part of each subsequent cut to flex and could partly account for some of the differences.
That’s a great point. I filmed all of the cuts so I just double checked and I cut all of them from shallowest to deepest so it’s probably worth trying some new tests in the opposite order as well as making the cuts further apart (no fingers) or supported just to test that out. Great point that I should have caught! I don’t suspect it will have much of an impact on the outcome but I could absolutely be wrong about that. Thanks for the insight.
You can see that the MDF is flapping around.
Sorry LRN2DIY, I gave the video a thumbs down directly when I saw this.
I was thinking the same
@@LRN2DIYwtf… Why even bother posting this? Absolutely useless video and a complete waste of time.. cool
Rotate the blade backwards a quarter turn to engage the super secret locking mode the pros don't want you to know about.
😂
I saw a video showing how to get clean cuts by doing two passes, first only a few mm deep, second cut through the remainder of the board. Seems to work well if you need a clean cut?
My late brother was a wood machinist for about 50 years and always said saw teeth should just clear under the board being cut. I don't use a power saw very often, so I follow his advise and keep the blade about 1/8 inch. 🐯
I was taught in my Wood Technics course in trade school that just past the bottom (or about 1/8") is best. The reasons given is that puts the most teeth in the cut and for safety.
All of the blades you purchased are thin kerf blades. Blades use to have both clearance at the sides and set the teeth angled away from the kerf. No longer the case.
At 2:18 that is BECAUSE the blade is shallow. Blades have usually two features to consider. One is pull down or hold down. Some blade protruding below the work tends to suck the saw down toward the work. And side clearance. Lack of side clearance creates heat and friction. Blades used to have set. They, with few exceptions,, no longer have set,, the lack of clearance makes them prone to side friction,, from accumulation of sticky tars from the materials being cut or the heating of the blade causing it to warp.
Thin blades are there to make more money for the manufacturers.. Ain't no other reason.
Your test. A perfectly sharp brand new blade 8 teeth or 60 teeth it will give a nice smooth cut.
Hand circular saw tests should be with a used blade,, your file dulled the file against the carbide and the blade is still perfectly clean. Every blade I have or have thrown away the sides of the blade or the sides of the carbides are covered with brown smootch.
The least friction on a blade is when the blade protrudes past the work by about 1/2 to 3/4 of an inch. The blade is doing its cutting on the upstroke on a limited cutting face. And deeper is not good because more of the dangerous blade is sticking out and the deeper blade can have vastly more friction and heat. Table saws same principles. 1/2 to 3/4 of and inch so the blade is sucking the work down against the table,, shallow it is trying to throw it,, too much sticking out a danger to hands and fingers and greatly increases the friction and heat.
Objections,, no smootch on the sides of the teeth or blade,, and the way a hand circular is used is an 8 foot rip to a chalk line.
All cross cut blades have teeth angle away from the kerf.
@@Sailor376also modern blades have carbide bits which are generally thicker than the disc providing the clearance that set used to. The blades published kerf is greater than the disc gauge. Thin kerf blades have less clearance.
I was taught to reduce the depth to the minimum required to make the cut, mostly for safety reasons. The 'full-depth theory', however, was once explained to me as being safer because the blade, despite the turning force, would be acting on the material in a more vertical action, rather than horizontal, thereby mitigated kickback. I've never been convinced, and I've always stuck to what I was taught. As for quality of cut, well, this video is very helpful! 🙏🏽
The less the stick-out the more teeth in the cut, and each tooth takes a smaller bite, less work for each tooth, less force needed to push, and usually a smoother cut. NB, that works as long as you can keep the saw from lifting and the cut straight. If those are a problem, deepen the stick-out. Works for table saws, too.
Don't plunge straight down, put the front of the foot on the piece, aligned with the cut and gradually lower the blade into the cut.
Hard to judge because cut quality is too dependent on feed rate/force and keeping the saw straight. Both can make good cuts if youre careful. A shallow blade at the same rate is taking a shallower but longer bite. Full depth is more dangerous for exposed blade, but less dangerous for kickback when the wood pinches. I use both methods depending on what I'm working on.
Just curious how did you make the same force for each cut? It's amazing to me how you can clean up a cut by going slower. How did you make sure you were going at the same speed?
Suggest you do some test cutting using "painters tape" on plywood to see if it minimizes tear out... Ive seen videos of woodworkers doing this and wonder if it does eliminate/reduce tearout particularly in cabinet grades of plywood.
Thanks for this. As some mentioned there was some lack of control in the testing, but guess what… there is no control when the average homeowner makes a cut an either.
I wonder if the saw tips more side to side when the blade is deep. But doesn’t matter here…. Results for how folks typically use a circular saw are useful.
I always set to about a 1/4" - so this is a welcomed tip! Thanks for doing the extensive testing.
Was taught that gullet depth was the way to go & never really tested it. Some new things to think about & test. Thanks for doing this!
You are correct. Setting the depth to the bottom of the tooth profile (the gullet as you said) allows for proper removal of dust/debris while cutting. I went to college for woodworking and this is what they taught.
@@joshuawiedenbeck6944I don’t understand that theory. Sure, the debris can’t be cleared until the gullet is exposed, but it’s only completely covered for a fraction of a second at the front edge of the cut. You have nearly the entire rotation of the blade for debris to fall out.
@@StolenJoker84 There are a lot of other reasons as well (like balancing safety with needing the teeth to provide downward pressure on the material), I just commented with one of the more important aspects. Heat dispersion is another....
@@joshuawiedenbeck6944 For head dispersion, don’t you also have the entire rotation of the blade? You also have the thermal mass of the blade as well.
As far as “downward pressure” … aren’t you putting downward pressure on the piece when you’re holding the saw, and you still have the down force from the rotation of the rear edge of the blade.
(although, I acknowledge that this may not apply to table saws)
Don’t get me wrong, I am not trying to argue anything, and am just trying to have conversation and understand the theory.
@StolenJoker84 The downward pressure has to be greater than the upward pressure on the back end of the blade. If the blade is too shallow, the blade can actually force the piece upward. For heat dispersion, if the wood is trapped in the gullets at the time of the cut, there is a chance the sawdust will get packed into the gullets and will have a harder time to eject. The increased heat also compounds. And as soon as heat gets to the point of burning, the blade loses sharpness extremely quickly. It's a calculation that CNC operators have to take into account when they run their machines. Chip/saw dust size affects heat dispersion drastically.
When cutting the plywood, the fibers of the veneer were being pushed by the dull blade, instead of being severed by a sharp blade. That's why there was massive tearout. The veneer is so thin that, when the spinning blade exits the top of the plywood (as it cuts on the up-stroke), the blunt edge of the blade pushes that layer up, and the glue fails, causing the layer of plywood to tear away, wherever the grain to glue bond is weakest. I bet nobody has ever tried this, and I should probably make my own video to demonstrate it, but I'm hoping you'll read this, and make a video, because the physics behind it makes me think it will work as I imagine it. Place your saw at the end of the sheet of material, so you can set the saw blade depth. Set it up so that the blade protrudes from the bottom of the saw plate, just deep enough so that it will cut all the way through the material. Then rotate the blade by hand to put the tooth at the front edge aligned with the position it will be when it exits the top layer of veneer, one its way up, as it cuts. Now, adjust the depth of the blade to get that tooth so that it exits the top layer at a 45 degree angle (45 degrees pointing away from the saw, towards the direction of the line to be cut) as it exits the wood on the way up. That will create a shearing action as it exits. If you think about it, if you set it up so that the angle of the tooth is the other way, the tip of the tooth will hit the top edge of veneer as it exits, effectively slapping that top layer from the back, instead of shearing the wood. Again, I'm betting nobody else has ever thought of this, because I've never heard it explained this way - but it just came to me, and it makes sense, as the definition of cutting wood should be to sever the fibers as cleanly as you are able - and my use of hand tools, including very sharp chisels and hand planes (sharpened to 16000 grit, on a Shapton stone) has proven what really cleanly severed wood looks and feels like. I'm sure this post will get buried - but it would be fun to see a video. And if nobody makes one, maybe I'll do it myself, one of these days ... I'm going to subscribe because I'm going to hope that you read this post and try this, and make a video.
You need a more steady hand with a shallow cut. With a deep cut the blade helps guide the path. Something to think about.
I learned how to use a skill saw on Ryobi battery saw. I learned really quickly to extend the end of the blade no more then 1/2 the with of the blade. It just worked better for that under powered saw.
excellent video my dude! I never gave much thought to cutting depth before now but have usually always stuck to about 1/8th inch simply cause it seems like the safest way to do it. its really nice to see that it also gives the best cut. 10/10 great video!
Nice simple test and all the results next to each other. Also shows that a guide fir the saw is needed where possible as there is a clear sign of blade cut wander with just the slightest movement of the saw. And. Cut veneers upside down with a guide.
I always set for a maximum depth of half the gullet and a minimum of about 1mm or 1/16” below…within this range I don’t measure it. Works for me at least on sheet goods. I suspect the full gullet used, to clear the chips, is more pertinent to thick boards where the blade is scooping waste out of a two inch tall kerf.
Here is my answer before watching.
Half the tooth cutting depth. Never past the gullet. If you can run a circular saw freehand perfectly straight, sure and go full depth.
The cutting edge kerf is wider than the supporting blade. However, add in any factors such as, you’re a mere mortal and don’t always make a perfect cut. Support of the cut underneath or the lack there of. Or even variations in material thickness. All that can make contact with the blade stock. Not a problem if it’s only the teeth in the cut.
If you use the least amount blade necessary, the saw is using all of its energy into the cut. And finally, you are getting more teeth doing the cutting work at the same time over a longer time vs a few teeth hitting in the front for short moments chipping out the wood. This is also easier on the blade.
On your demo I was thinking “chatter” (others call vibration) from the cuts being so close together (lack of support).
I’m no great sawyer but I’ve found over the years that about a “thumb” or 1 inch projection works best overall for cleanliness and control.
I’m no “scientist” just my observation over thousands of cuts.
There is one thing you DON"T mention i n this video, and I have never heard mentioned in any video, but have proven to myself and my co-workers time and again. If you set the depth shallower (i.e. 1/8th to 1/4 inch through) the lower blade guard works WAY better, and is less likely to make the cut go off line as you enter the board. Just a personal observation I wanted to share.
I worked in a machine shop that had burned down a few years before and lost their plate saw. Turns out, you can cut plate aluminum with skilsaws just fine. We did all the way up to 6 1/2. The blades all have carbide teeth now anyway, so you don't even have to worry about overheating.
The thing about carbite that they taught me is thay it doesn't like interupted cuts. It doesn't like inadequate cooling either, either drench it or leave it dry.
So what I did - which worked out pretty well - was set it to just barely make it through. This kept the teeth partly in the material, so not an interrupted cut. It also reduced the amount of the blade that was in the material, which reduced drag (pretty big deal on thick stuff) and made pinches less catastrophic.
My experience on wood as it concerns cut quality has been that it has more to do with the chip load you run the saw at than anything else. You push it hard and it'll cut fast and make a mess. Real slow and it looks great. Beyond that I never really cared. I'm not a carpenter
I cut Aluminum plate with hand held circular saw as far back as 1984, always keep blade wetish with WD40 ( about all it is good for) to help with reweld ( Aluminum sticking to the carbide). Same process on a table saw.
I was taught that the full depth cut was a recipe for kickback. I actually experienced that first hand. Nasty accident.
This is why you need special guards and tools when going full depth. It is only recommended on a heavy table saw as it's absurdly prone to accidents and the mass of the table is all that's keeping it together. Even when using a table saw in a wood shop, we set it to barely poking out above the surface unless the material required it. Some things simply don't cut well except very slotly at nearly 90 degrees. Yes, kickback is a real factor if it happens and it rarely ends well. Seeing a piece of wood shoot 20 ft across the shop brings home safety real quick.
Add a sacrificial piece of board on the bottom and make sure the depth of cut not to exceed 1/4 of the bottom piece. Also added tape to the blade kerf on the board will help with the tear out (but who has time for that?).
For the cleanest, make the cut in two passes: one to a depth of 1/8" (only scoring the face of the board facing the sole of the saw), then a second one to whatever depth you want.
Also, missing from the material list: particle board (not MDF) with a melamine surface - that's the most unforgiving when it comes to the quality of the cut (the particles are just waiting to explosively leave the material taking a bit of melamine with them).
Good to see the safest depth gives the best results. Makes sense too, the smallest exit angle would produce more shear and slicing than a blade 90 deg to the workpiece. Thanks for doing this!
`Something I discovered around thirty years when making furniture pieces using a circular saw (before finally buying a bench saw) was blade wobble. Didn't matter how deep or shallow the blade was set, my fairly new 9, 1/4 circular still had slight play in the shaft bearing which resulted in tear-out on the back side of the blade. Circular saws are certainly better now but I'd struggle to believe they can compare to a bench saw doing the same thing.
One thing I thought you would be testing is how much force/effort it would take to push a blade through the board; how easy is to to cut at various depths.
This is neat, but I have a sander. If I ever want a clean finish, that's what I typically use. Thanks for the time taken to test.
I agree with clean cuts in mind, but it seems like full depth cuts faster and stays straighter if you are freehanding something like OSB.
I think what's not mentioned here is blade angle. I noticed on a few circular saws I have (good brands) that the front of the saw cutting edge is at a very slight parallel angle compared to the rear cutting edge. (not the bevel angle) I believe this angle, even millimeters, can affect how clean the cut is. Something to look into. There is no way usually to adjust for this angle, as it's factory set most of the time, but it exists.
Wonderful to learn the overall best results is also the safest.
Milwaukee says in the track-saw manual "The blade should extend no more than 1/8" (3 mm) below the material being cut."
This is a second comment - because my other comment was already very long (but worth reading) ... My thought on why the full depth cut gave a messy cut on both sides; the blade isn't supported by the wood as it cuts - the entire blade is spinning freely below the wood being cut, and that blade can vibrate a lot, since there is nothing keeping the blade stable, as there is when the majority of the teeth are between the wood fibers as it cuts.
It really depends on the material. Pine wouldn't matter, but laminate is very sensitive to chipping.
What about the best setup for Dust collection ?
In your previous video you showed methods for getting good quality (lowest tearout) cuts, but it doesn't seem like you used that here. It was also be nice to see this done on a table saw where your hand movements would have less effect on lateral blade movement.
Quick question. I know the blade should stick just a bit out of cutting material. What if I've got stair treads with nosing . Obviously the nosing drops down twice of size of the tread. How to set the blade depth when you've got 2 different sizes in one piece of wood?
I cut full depth unless I don't have the clearance. Reason is safety and control and I understand physics and leverage. Cutting at full dept puts the reaction force exerted through the blade closer to the center line of the saw and it puts less force pushing the saw back and more force into pulling the saw directly down making kick back less of a chance.
I've been using my saw for regular projects around the house for years. I finally realized I should replace the blade so I went to RUclips for information and found this amazing video. Thank You!
At 3:45 mark you introduce the only thing that is important: the cutting angle.
At 1/8", it is minimal, while at full depth it is the closest to being perpendicular to the board.
Now decide for yourself if you want the saw blade teeth to attack your board almost tangentially (probably not good for the far end of the piece you cut), or you want them to fly across the board (bad expectation for plywood, as you can imagine).
When using a stamped steel shoe, like on a Ryobi, you don't have too much choice but to use full depth. The flexing of the shoe is more of a problem than the blade. If the blade spins too slow, the ply will force it off the cut line. Even with a guide.
That's always been my go to depth...the minimum protrusion that still gives you a clean cut.
You'd think this would be fairly obvious; I mean that's how I arrived at it.
But logical, and what people talk themselves into are rarely the same things.
Good test.
Thanks
I think a lot of people use a bigger depth than they need when they're working on a project where they're cutting multiple thicknesses of wood.
Being lazy so that they don't have to keep resetting the depth. I've been guilty of this myself but this is definitely been an eye-opener.
Like your last video I saw, I find your videos extremely informative! Thank You!
this video deserves a like and a comment.
Smallest depth/height will make clean cuts, with small and minimal burrs. Greatest depth/height will have more power, will cut faster and push the board/timber/etc down or towards the sole of the saw.
I forgot to mention grain orientation. That's also important for choosing the right blade
Thanks. I’ve always wondered about that. And now I know! 👍
Cut where/how you are comfortable.
Don't let anyone tell you where your "comfort zone" is or should be.
If you need this test to tell you full depth is the worst for tear then you haven’t used a saw much ….but good idea to try and test the depths even if the method might be flawed
1/8 also puts less load on the moving parts helping with longevity.
The other problem with "F" is the saw has to be held 𝒑𝒆𝒓𝒇𝒆𝒄𝒕𝒍𝒚 straight and true inline with the intended cut direction. The less deep you cut, the less a wobble in your grip will effect the outcome.
Agreed. That shallow blade makes it easier to stay on track since more of the teeth are engaged at all times, helping to keep your path true.
In following a line down an 8' sheet of plywood, not using a straight edge or track, it's not about how many teeth are engaged that keeps it straight, but how much of the full diameter of the blade is engaged. Using the smallest cross section of the diameter, the easier it is to turn, so yes, less chance of kickback. With more diameter engaged, the harder it is to turn out of its kerf, and the saw will almost track itself, and holding steady, you will get the straightest cut. Sometimes "clean" is not defined by a lack of tear out, but by how straight a freehand cut is. Face down will usually come out clean either way.
If I need to cut face up and it needs to be perfectly clean, say cutting laminate countertops, I will put masking tape down.
If you're cutting a large beam that is beyond the depth of the saw, where you have to rotate the beam once or twice to get all the way through, at full depth you can feel the saw track in it's own kerf.
So, of course, safety and proper setup is priority either way, but blade depth is always determined by application.
I don’t bother adjusting for 2x material, though I probably should. But i typically just eyeball it for plywood or melamine cuts and set it that way
To me, the depth of cut really only matters according to the situation. If I'm just cutting wood on a set of saw horses I'll just let the blade cut all the way down. On the other hand, if I'm cutting into a floor to replace a bad section then I'll limit my depth to just over the thickness of the floor so I don't also cut halfway through the joists, lol.
Does this pertain to metal cutting also
Great testing! I don't do that much with a circular saw (yet). But 1/8th it will be! :-) (or just over 3mm, 'cause we use those over here)
I found the cleaner cuts come from about a quarter of a inch but that might differ between rpm of the saw mine cuts at 3500 rpm I think it's the cheap brushed Milwaukee
Consistency is the was to get the cleanest cut and using the right tool or method. If tearout don't matter I freehand, if consistent size matter I would use a guild. If you need to limit tearout use a new 40 tooth. Fewer teeth makes faster cuts and better on harder materials. I tend to use 3 saw teeth sizes: 24 and 40 for 7 1/4 saws while 40 to 60 on 10inch blades. If you need perfection use a router.
Something not covered is blade flex. Deeper the blade the more flex there will be and more blade wander, especially with a dull blade. It was pretty evident in some of the full depth cuts shown. The full depth kerf was wider and not straight. Been an 1/8” guy for nearly 4 decades and looks like I’ll continue cutting at that depth.
Who thought full depth was a good idea?
I learned in grade school wood working class you only expose as much of the blade through as needed to cut the wood and ensure sawdust is expelled.
One issue that wasn't touched on with the full blade is that it can also lead to a blade getting stuck in seizing in a cut if doing some cuts that aren't flat.
followed immediately afterwards by either the breeaker tripping or the piece getting shot 30 ft acroos the shop.
I think using a table saw might get even more accurate results narrowing the margin of error created by the human factor and have better test results on just the blade and machine. Kinda like sighting in a rifle standing vs using weighted sled and support stand.
Yes, a rip blade will cut plywood just fine, but a plywood blade will cut faster and last longer between sharpenings. I, however, no longer use plywood blades; I just use an 80tooth carbide-tooth blade for everything except long rips. (Most of my saws are 10".)
You could have did a control 1/8th in cut at the end so you could see if it was being affected by previous cut.
Thanks this is good info
The difference is cuts is very subtle IMHO. My concern is dulling the blade. I want the longest blade life, because $$$.
(I could be wrong but… ) It seems to me that the blade stays sharper LONGER, the less time it has to make contact with the wood. The shallower the depth the LONGER time the blade has to be IN the wood. Also, I would expect that the temperature and therefore blade heating, and the increase opportunity to burn the wood as well. So, those are two reasons that, I still think I’ll risk the “full depth” cut. Keep up the GW.
I thought i saw you on a different channel about 3D printing
What is that channel?
Thanks
Hi there. I have another channel called The 3D Printing Zone. I have two other hosts that help to run that one too.
Nils Great minds think alike. The rule of thumb I have always used is half the distance of the tooth which is typically about an eighth of an inch or so. On my table saw I will sight the blades so that it just barely sticks up above the wood by half of a tooth.
Makes perfect sense, Jeff. I suspect if I did the same tests on a table saw the results would be about the same too. The half tooth makes sense and I have a very healthy fear of table saw injuries so I keep that blade as low as I can get away with.
I was taught to set the depth to half the height of the tooth. 1/8" is pretty close to that.
Try to angle the teeth at 30-45 degrees to the top surface of the material, a 90 degree tooth that is perpendicular to the surface of the wood has the most surface area to slam into/ tear up through the fibres rather than cut them.
Here is one for you the teeth do the cutting the gullets help to clear the sawdust from the cat / kerf. Dropping the blade 3 inches farther than you need to just adds to the friction between the blade and the material you are cutting. Why the hell would you want the blade up by the arbore coming in contact with the material unless you have to while cutting the max depth of the saw
Nice video. I"m a beginner and i have a question: Is it useful or overkill to have 2 circular saws, one with a special blade for ripping and one with a special blade for crosscutting, because i don't like swapping blades, making the circular saw screw dull. I also have no table saw and i don't think i wil have one soon, because they are expensive. Hope to hear from you soon. Many thanks in advance
Two saws are good, but not just for ripping and cross cutting. If your saws are 7 1/4-in get a 24 tooth blade for ripping and cross cutting lumber. The second should be for plywood, and a 40 or 60 tooth blade is recommended.
Don’t know where you’re posting from but around here used circular saws are almost free.
If you think you will realize that on the shallow ones the blade is cutting more of the time than the deeper ones, as the deeper ones pass through the wood, whereas the shallow are staying in the wood.
Full depth on the blade should help with a straighter cut, due to the diameter of the blade acting as a straight edge. Plus, full depth lowers the centre of gravity of the saw, and makes the position of the handle more comfortable.
You may get a cleaner and safer cut with 1/8" but you have barely any side to side stability which makes long freehand cuts much harder to keep straight.
I noticed that all your cuts were on the same board. Could the vibration of the narrow wood contribute to more vibration in the board and thus messier cuts?
Someone else had mentioned that and I wonder the same thing. I'll try some additional cuts where they're way spaced out and see if there's any difference. I can then post the results in a pinned comment here.
Nils, It looks to me as the kerfs for the full depth cuts were always wider than the others. Possible?
Possibly, the shallower depths stabilize the blade somewhat, but the full-depth amplifies any wobble/vibration imparted by the motor.
Your 1/8 inch is cleanest because it’s your first cut… You then cut within 1/2 inch of your last cut causing a lot of vibration in the material between cuts. The tear out causing a worse looking cut is due to lack of support.
I was told when I was a child, plunge the blade just deep enough to show the entire tooth. Has always worked for me, cuts start getting ugly, replace the blade. More teeth, slower the cut, but better looking, looks don't matter, speed preferred, low teeth count. All pretty simple.
Several manufacturers say that 1/2 of the carbide tip should be exposed. Not far off from what you got.
Thank you, common sense ftw!
Thank you Sir
Its all about tear-out. The more perpendicular the blade teeth are to the work piece, the more tear-out. With more angle of the cutting edge or shallow the cut, the less tear-out.
Im the boss of no one. I can't agree with your safety assessment. The saw cuts and you lose parts no matter the depth. Plus there are other places othet than underneath to get into the blade. I find that a deeper depth helps me stay straight all the way down long cuts because a longer section of the blade is engaged; safer and a better cut. I also feel "kickback" of the saw and material is reduced because the contact areas of the blade with the material are more vertical, especially at the initial front cutting zone. There are also many times where blade depth is dictated by more than the ultimate cut quality. The thickness of the material, stuff that hits the motor like sleds and clamp down fences. I do this it was a good and worthwhile video, rhanks.
Please do not listen to this man. 35 years of experience says this is all wrong. Skill is required to make a straight cut. The saw blade cannot do it for you. Full depth cuts expose you to more chance of violent kickback. The back half of the blade is pushing the the saw up from the workpiece. If kickback begins, the saw lifts up, and is then pushed back by the bottom of the blade as it comes through the material. All in a fraction of a second. You want to limit the amount of blade exposed to the material. Maximum 1/4” of blade exposure. You get better results as well, as shown in this video.
Please be safe.
There's been times where something underneath couldn't be cut, so I'd set the depth to a hair less than the cutting materials thickness.
I’m thinking you could make a small riving knife for a circular saw.
Seems I've heard that a minimal blade height above your wood on a table saw is the setting for a clean cut. Seems the same would apply to a circular saw. 🤷♂️
Found an issue with your testing, At ~5 minutes you show a slow motion of the multiple cuts on the wood. You are putting the cuts too close to each other, the wood is flexing and bouncing back and forth...
thank you
I didn’t know there wS a debate. I always went shallow. It always seemed the safest too.
It would actually work better at full depth if you were cutting metal. Granted, typically we cut metal with bandsaws, waterjets, laser cutters, or plasma cutters, but the less distance the cutting surface has to travel while engaged in the cut, the less heat and resistance it will have. That's why you really only typically see circular saws cutting bar stock in the world of metal working, as well as some other very specialized applications like slitting.
Thanks !!!
Excellent video Brother
Thanks, Will. Have a good weekend, my friend!
@@LRN2DIY you too.
@@LRN2DIY please make a video about sharpening lawn blades.
Very well done 👍 Thanks heaps for your thorough demonstration and the time and effort that you put into this 🙏