Many years ago, when I was but a youth, I was using lawn mower blades for a steel source for woodworking tools. In my research I discovered that they were Aus-tempered. This is an industrial heat treat for assembly line work. If you want to know what kind of steel they are made of just use a grinder in a very low light almost dark area so that you can see the sparks coming off. If they look like a sparkler, then you have a high carbon steel, if they are small round sparks then it is low carbon. You can you tube the different sparks produced by different steel types or look it up in an old industrial arts book or blacksmiths book.
My dad just used to make new blade tips, using the machine shop ( and getting the crew to make him a stack of a few dozen at a time when they were idle) at his office, and just used to bolt on new tips when the old ones wore out. Basically a triangular shaped steel strip, sharpened along the diagonal and with a M8 hole in the end. They would last around 3 months in summer when the grass was growing fast, so we would use a round 3 sets a year, on average. Our yard had both a good collection of pebbles, and as well Turpentine nuts, which are also hard. The tips were bolted to the old blade, cut short, and just snugged up with a M8 bolt and nylock nut so they could turn with force. Bolt would last about 3 sets of blades before you had to cut it off as it was worn round. Steel for the blades was whatever scrap steel the shop had, typically offcuts from repairing trailer floors, made from 5mm steel alloy sheet.
Straight out of the box I run the cutting edge right up to the spindle cup. This does two things, 1) provides more air velocity for grass blade lifting action without modifying the wing and 2) provides more cutting surface for faster ground speed. I have a blade balancer for keeping blades balanced (simple stepped cone on a point). I do all my initial cutting edge mods on a Bridgeport mill (set a stop for fast, precise repeat-ability and fast metal removal). Mower is a John Deere 755 with a 60'' deck.
What I was able to find out when I was trying to research mower blades is that they are made from a carbon steel and hardened to 38-42 Rockwell. It's probably made out of similar material as leaf springs. Carbon steel nickel alloy for resistance to wear. You don't want blades that are too hard because of fracturing and having the possibility of fragging anything around the mower. Mower blades are made to dent and bend on impact of hard objects like rocks. I'm pretty sure they heat treat them in a salt bath too to keep the blades from warping during the heat treat. If you'd like to try a steel with high wear resistance I would choose something that could be case hardened while maintaining the ductility of the steel. 5160 might have the properties you need.
@Cyclone Bravo Would it not work say to heat the cutting blade to black/blue hue and quench in old engine oil to harden not to hot as to make it to brittle ?
Hey Jim, nice project. The "lift" or fan blade effect isn't necessarily for grass catching bags or even for moving the cut clippings out of a chute. The blades actually "pull" the grass up so the cutting edge can get a clean cut. Without them the grass would just fall over and you will be making crop circles. Enjoyed the show.
I feel you on the cost. Welder/FAB man here as well. Back in '99 I bought my first finish mower.. 5ft RHINO. First thing I did..removed the blades, so I could 1: Add anti seize to the threaded bolts 2: cut 1 inch away from the front ( now this is a common practice on new mowing decks..) 3: I did a grind test on 1 of the blades..yep they were cold roll. Thus I brought them to a slow heat to just were you can see the red start..then focused on the edge that would be sharpened. Got that bright red a few times hardened it out. Now keep in mind that was summer of 1998. I am about to replace those blades at the end of this summer. obtw.. This mowed is used on several 5 acre plots as well I raise it to do light bush hogging on the garden.
I have been replacing the outboard 6" of metal with 1/4" mild steel, bending a wing, and sharpening it. Has worked well for me lasting longer than a factory blade. Yes I am an experienced welder and have 62 years of welding experience. I weld them with a MIG after clamping to a piece of 1/2" metal for alignment, deep V groove the abutting pieces, weld them and flip it to other side for repeat. So far I have been successful with balance. Test each one with a pin horizontal in vise and hanging blade on it. For Jim; wings will be necessary to create enough wind to clear clippings from under deck. Yes, I live in a sandbed also. GOOD LUCK!
I have made blades from truck leaf springs in the past, they will chop through flints without too much damage, I have also built up old mower blades with face hardening rods with a fair success.
A long time ago we had a lawnmower that had sickle sections riveted on the ends of the blade. When to dull to cut put new sections on. Thanks for the videos.
most mower blades i have seen have a unique center hole that is not easily duplicated in the home shop. i have never known anyone that used up mower blades that quickly, thats some tough grass you have there.. i remember reading once that the bend plays and important role in lifting the grass to be cut. it should be interesting to see how that flat blade works for you.keep us posted.
Looking forward to the test results. I have a similar problem here in SE Arizona. I only mow during monsoon season as that's the only time anything grows here; mostly weeds with stalks tough as irrigation pipe. Our soil type is basically sandblast grit so blades don't last long at all.
Hi Jim, I cured my blade problems by grinding a cutting edge full length on 2 high speed steel parting tools and then silver soldering them into a stock blade body. I am only doing about 3/4 acre with a honda hand mower but they last about 4 seasons on one sharpening.
I used to sharpen lawnmower blades for a living. I serviced the equipment I was using. I used a 6 inch grinding wheel. It hollow grinds the blade giving it more life. I had spare blades and would check to see if the blade was dulled. I know it's just a mower blade, but when people are paying you, you want to give the them what they're paying for. The tip of the blade travels at 200 MPH, when it's dull it frays the blade of grass and opens the door for decease. And now that you're bored, after it's ground, it has to be balanced. They sell the lawn mower blade Balancers for 6 bucks at the home depot.
From my experiences, will depend on who made the blades as to the alloy. As been recommended several times already, hardface the ground cutting edge then do a final sharpen on the mild steel and it seems to hold up well. The wear on your old blades is more so on the lift wings and that is typical of mowing sandy soil (probably like what you have in FL). I think you'll find you'll want some lift wings to aid standing the grass back up after it's under the mower deck or it will look more like you cut it with a rough cut mower. Keep the lift wing angle low and it will hold up better. Hope this helps, enjoyed the video. Look forward to see more.
Try 1045, heat treat to Rc50, temper/draw to Rc35 or so. Works for me . Lasts a bit more than twice as long as factory stock. Buy it in 10ft sticks and the cost savings are substantial. Have had no breakage or bending issues yet!
I'm only three minutes in with this comment. I did once take my LH turning Simplicity blades and put replaceable knives from a discbine onto the ends of them. I bored holes in the end of the shortened blades to fit a stack of 3/8 lock washers (for a bearing surface) and used 3/8 grade 8 bolts for an axle. Worked great!! Got me out from under buying Hi dollar Simplicity blades. I gotta wonder about the hardness of your homemade blades, but as I said,I'm only three minutes into the vid.
The company I work for does rough mowing with a bunch of different mowers. Flail, hammer and knife, Bush hog type rotarys and multi blade units like yours. We often end up mowing broken concrete, bricks and other trash dumped in these fields. Even 1" thick hog blades don't hold up well to that kind of abuse. I have had good results with making blades from plow steel and abrasive plate. The plow steel is a cheaper 1045 hot rolled product, and I believe the abrasive plate is AR400 or AR 450 We get drops that are not always marked properly. The best thing was to rough grind them, then throw a bead of Stoody 31 hardfacing rod on the edge before doing the finish grind. They outlast the stock blades at least 3 to 1. Now the issue is mower deck wear.
My grandpa, would use hard face rod and build up the cutting edge, lift, and mower body. . Crosshatch on the mower body and the drag rails. My grandpa was one of the owners of McKee & Hamilton in Richmond, California. Machinist, Welder, Heavy equipment repair. He ended up the superintendent of the machine shop at Kaiser shipyard #2 in Richmond by 1945 -- not to shabby from being a mechanical/blacksmith/machinist in 1939 in western Nebraska.
Arizona here,try to keep a couple of sets handy, before they get to worn,build up, hard face sharpen and balance.or make a plate and do as suggested and use windrower blades
I did this for an old mower that they don't make blades for anymore. But I used a rosebud torch and heated the steel and hardened the cutting and lift area and it made a big difference with wear because hardened steel doesn't wear as fast as soft steel
I agree with the others who suggested hard facing, I don’t know what that greens stuff is that they call grass. We don’t grow much of it around here, we can’t drill wells and the water prices are WAY to high to think of watering a lawn
Hey Jim, most blades are a steel tungsten alloy. When I make a blade I usually use a hard surfacing rod with a stick welder on the cutting edge then do the final sharpening
exactly what I expected to comment, you can use mild steel for the blade fabrication and leave a provision for applying a hardfacing bead at the cutting edge and there a huge choice of alloys to do the cutting edge
I have thought about making my own blades too. If I do, I would use the blades from a disc hay mower on the end or rivet on sickle sections so they would be replaceable cutting edges. It will be interesting to see if mild steel works and if you need to bend any lift into the blades.
just a thought at one time I believe it was lawnboy used a disc with 4 replaceable blades. thinking it may be interesting to study a haybine and see how it could be adapted. great video's Dave
Thanks for your help.is your.pull.behind mower PTO drivven to get to the point most of the blades are 1/8 the inch shorter than than the cutting number of the mower pan I use a high lift blade on my snapper 28 inch hi vac then on my Husqvarna AWD mower i use a 5 or 6 point star blade the only thing is if it is not put on the right way ooops to the adapter I have to start over again plus the blade is not as thick as it should be also it has very little lift but I think it's a great idea you g Have making your own blades
Hi, Props for making blades yourself. I recommend the following instead: 1. weld new metal onto your worn blades in the 'lift' area 2. case harden the blades to resist wear
Looks like a money saving project and if they give satisfactory service, you could easily make a dozen at a time. I hit a tree root with my mower and bent the end up. It did not act like mild steel when I straightened it. Try bending an old blade to see what experience you have. It appears you might be cutting over sandy soil or mowing the edge of a gravel road to wear blades that excessively. If so, you may also eventually "sand blast" through your deck.
I have replaced conventional mower blades , with a disc .your farm store will sell you short swinging knives made for various disc type hay cutters. they also sell the pivot bushings and bolts . the knives are made in both right and left hand rotation. the knives can be flipped over as they are sharp on two sides. I mow saplings and anthills under the electric fence. I find a swinging knife to run smoother in rough cutting
The best steel to be used is carbon steel as mentioned mild steel tends to bend when hitting stuff in grass like sticks rocks if over grown i have done it with push mower it goes out of balance and destroyed the mower
I like the hard face idea for the cutting edge that Steven had. I would ad that if you don't need the lift then don't put it on. The lift creates vacuum. That's what lifts the sand into the cutting deck. The lift is destroying itself with its own function. So unless you're real particular about the cut I would try it without. I think you will find your blades will last a lot longer. If you're just doing a fields to keep the skeeters down you won't miss it.
I use mild steel for all my brushhog blades. Have done it for years. But balance is key for a mower. I also have a swisher 60" pull behind mower trail cutter. I use gator blades on it yes 20 each but I get about a year out of a set.
Jim, If you are not going bend the life edge of the blade then grind the edge on both sides of the blades so you you can flip them over and extend the cut..
I have a very small lawn and a small Chinese hover mower. It takes three 2 inch plastic blades which mount on three capstans underneath. They are expensive and last no time at all. I now make my own blades out of four inch lengths of coat hanger wire which I bend in half and then twist around the capstans using vise grips. They are not sharpened at all. They cut the grass perfectly well and mulch the clippings. They do wear out becoming shorter and break if you hit stones but they cost nothing and are easy to make. Jim. With your blades I would make a round permanent centre part and rivet seven inch long 'mini blades' to it with two rivets apiece one inch apart. This should be easier to balance and less wasteful. The round centrepart could have fins like my hover mower does instead of your wings.
Deere blades(not the cheap lowes/home depot versions) are a high boron and high maganese special steel. I believe they get it from Theysenkrupp. If you want to send me the dimensions on yours I can see if they have anything you could maybe modify to work.
Great idea Jim, but there are some considerations in any blade design, etc.. Right off the bat, there's something wrong. But I'll get to that later. First off, deck blades used in 42 to 72 inch decks are pretty wide as you have discovered. They have to be able to be lightweight and aerodynamically efficient while maintaining some durability. I say some because safety is the overall consideration. You are correct, almost all blade manufactures in the aftermarket use mild steel. These can withstand moderate temperatures and intentionally deform as necessary in the tight confines of the deck. Using a heavier and stronger steel is possible - but at the sacrifice of requiring more power (grip) around the spindle pulley belt(s) to make sure they do not slip. Some blades require a lot of torque to get through the grass (thin, thick, tall, moisture content, etc). which means the belt and pulley system needs to be strong enough (5/8" instead of 1/2", different V-Belt angles, size of pulley's and Idlers to maintain tension, etc.), all the while trying to use as little horsepower and maintain a constant RPM for the blade design. Running the blades too fast; the aerodynamic effect will allow the grass to simply bend. Too slow, it will only cut some of the grass and begin to clog up the deck walls (in a hurry). This leads to the 'lift' element of the blade design. It's critical or the blade will not work very well in most deck designs. The goal is based on the pure physical laws of aerodynamics. Suck the grass upwards so that as the blade swings around it's ready to cut. Without any lift, a lot of the grass will probably just bend over and only be partially cut - if at all. There are different types of lift designs used depending on how thick the grass is and what type, and time of season (spring, summer, fall, dry or humid) and environment (cold, hot, wet) for discharge, mulch, etc. The angle of the cut does make some difference depending on how thick the grass is. Most blades are designed between 33 and 45 degrees with the most common being between 30 and 35 degrees. Do not attempt to heat treat or harden the blades. Should you hit an object, it could shatter the blade and create a projectile strong enough to slice through your mower's deck. Seen it happen. The blades are designed to spin up to 18,000 - 19,000 surface feet per minute. This is the speed of the tip of the blades that can be reached - which is the maximum allowed under most safety laws across North America (i.e. OSHA). The wider the blade, the faster the tip of the blade is moving. It can get ugly in a real hurry.... With no lift on your blade design, you will easily exceed this (speed) limit because there is no aerodynamic drag and would be very dangerous. The trick to maintaining lawn blades is the quality of the steel, lift design and ensuring your pulley system is in good running order. Given the number of times you cut your grass and the size of your acreage, I would test a number of different types of blades and then once you find one that is suitable, buy them in bulk. The key to keeping them sharp is making sure all edges are straight and no nicks are found on the cutting edge, side (tip) of blades AND the lift edge (top). I suspect your mower deck (which you describe as a pull behind) is running far too fast a SFPM and the key reason your blades are being destroyed. The primary drive pulley that runs between the deck engine or PTO, should be 1:1 RPM. As you already know, PTO's are available in 6 spline 540 RPM and 20 or 21 splines for 1,000 RPM. The main pulley now has to be matched to all the Spindle Pulley's (Diameter) to ensure it is running at the right speed. If the pulley's have been changed and incorrectly replaced, that would explain a great deal why your blades are destroyed after 4 cuts per month. If the deck has its own engine, make sure it is running at the proper RPM (maximum 3,200 - 3,300 RPM in most cases regardless if it's a Single or V-Twin). Send me a PM if you have any questions (We've talked before). Good luck!
Wow! Thanks for all that info. That was great. My tractor is turning slightly under the 540 pto rpms because I keep the throttle back just a bit. Everything is stock. What folks are not catching on to, the problem isn't the cutting surface, but the lift where the sand contacts the "ranp" part of the lift. It literally sand blasts the blade away. So far the blades have worked better than expected ( blades #2 is being edited now.) Still more work to do, so far it's not to bad. Thanks for watching.
I spoke with Rotarys engineering department. They don't make anything that will work. The blades have a Kubota number stamped in them, but that doesn't help ...
A number of machinist friends of mine would call dykem DICKEM. The metal used in lawn mower blades is just what you have mild steel. This is to make sure that a blade will self destruct and not shatter on heavy impact. The newer blades are using a tougher alloy steel. But be careful fella, getting hurt in an easy thing to do.
Some of the videos I’ve watched of amateur smiths trying to make knives out of lawnmower blades speculate that they are a low grade of spring steel. They seem to be able to be hardened some but not a lot and share some similarities to leaf springs in spark testing but not quite the same. Not sure if this helps, wish I knew something firsthand to share.
What I've found so far, is that different runs of blades (even from the same manufacturer) seem to differ in material hardness. which make me think the use what they can get a good deal on.
An Aussie friend of mine had to keep the grass down short around his place, something to do with state law and wild fire management. Couple of sheep and a goat. Turned his time mowing into tucker, as he said.
I think you might be onto something, that lift creates a vacuum to pull up the grass but it also probably pulls up rocks and dirt, thus shortening the life of the blade, also be kind of cool to make blades out of an iron that you can flame harden.
If you want to make your blades last a lot longer, go to a welding supply shop and pick up a can of hardening compound (arsenic, I think), get the cutting edges red hot and sprinkle the compound liberally over both sides of the cutting edge. You should easily get about 8 times the longevity out of your homemade blades. Try it, it totally works! :)
Hey Jim Check out Meg-Mo systems. It might be just what you’re looking for. I’m not affiliated with them. I’m just tired of paying outrageous prices for blades. You could make a two blade version easy enough. But I like the idea of four per spindle to reduce wear/blade change interval.
I am pretty sure most lawn mower blades are made of mid or high carbon steel. Like 1045 and heat treated and tempered to a hardness of 40-45C. Heat treated 1045 would work quite a bit better in your application i would think.
Try drilling a hole in one of the old blade. This my give you some insights about the materialI the blades are made of . I need to make the center hole bigger in a new blade for my grandfather this blade work Hardened every quickly an I had to drill it from both sides .so my suggestion on material is something that work hardened T1 or weldox
The mower wheels and rollers on the deck lay the grass down. The lift part of the blades are there to lift the grass up so the cutting edge can do its job correctly. The discharge coming out from under the deck is created by the lift of the blades. The lift creates an updraft that must find an escape route from the area above the blades . That up draft causes the grass to stand back up to be cut . If your blades are wearing out at the lift area, you have your deck to close to the ground and lifting grit along with the grass . Raise that deck a little and make your grass healthier and your blades last much longer. Fab Tech Tom
Jim it may be presumptuous did you balance the blades? I don’t have the same problem, however I keep 2 sets of blades for my mower. Change then sharpen, all I use is a screw in a post where my outside grinder is. You can do the same with a 1/4 rod clamped in a vice. This is one of the first things my Dad taught me in fact stressed that to me. Another thing is I’ve shown this, I have an inexpensive flea market vice mounted outside of my shop just for those messy jobs. Mainly for knocking rust off of stock. Enjoy your videos
You could run some harden beads across the edge and regrind to slow wear. Use some electrodes take the flux off and tig it on if you dont have anything else.
I make my own. Same bar stock. But even cross marking them to center the hole is close. You'll probably still get vibration. I balance mine . Hard tipped point, on a ridged bench.. find center , (takes a bit of time) . Hold it and tap the bar to center mark the hole.
My cousin would heat them up and hammer the wings flat. It cuts fine and is easier on the mower. Seeing your video I am going to try a set of flat blades. It's like bush hogging. But I have seen where mulching blades were better used on tall grass Becouse of it wrapping around mandels.
It was a 4 1/2" 40 grit zirconia flap wheel. I'm away from the shop, but PM me if you are interested and I'll get you a part number. They worked awesome.
Make sure your kids are no where around when you use that. Just incase something breaks and fly's out of there. I had an edger blade break and stuck in a tree right next to where I was standing, when someone else was using it.
I remember when i was a kid, the blade broke on my old mans mower and he only found half of it, made you think if some one was near at the time because we used to like towels through the cut wash.
Additional Comments: One piece blades should never be made out of hi-carbon, alloy or tool steels. Once heat treated they do not have the ability to absorb shocks from high speed impacts. Two piece pivoting blades that are found on commercial mowers (bush-hogs / bat-wings) are able to use blades made from higher carbon steels. Retention of a good cutting edge requires a hardness of around HRc 52 based on application. OEM mower blades have a hardness of about HRc 38 due to the boron steels (cold rolled 10Bxx) and the austempered heat treat used to harden the blade for ductility. A differential heat treat process has been used in production where only the cutting edge of the blade was heated using an induction power supply, quenching in place with a polymer (water base) quench and the entire blade tempered at around 300'F. This process increased the hardness in the cutting edge increasing the intervals between sharpening. Some of the cladding processes of the edge mentioned in the comments could work. Care must be used to prevent tempering (lowering HRc harness) behind the cutting edge. Some type of heat sink (water cooled) could be made to control the affected heat zone
another option on the blades is cut 3 steel discs and bit blades from a agricultural hay cutter the disc just need to be the diameter of the old blade less the lenght of the bolt on blades that way they are easyer and cheaper to replace and because of the bolt on blade swing they break less there is also the option of fitting 3 blades per disc to speed up cutting
Meg Mo is a commercially built blade system that essentially does that but I don't think they use off the shelf disk mower blades. Jim could easily build his own disks to use disk mower blades that are only a couple bucks each to replace. www.meg-mo.com/meg-mo-blades/
Many years ago, when I was but a youth, I was using lawn mower blades for a steel source for woodworking tools. In my research I discovered that they were Aus-tempered. This is an industrial heat treat for assembly line work. If you want to know what kind of steel they are made of just use a grinder in a very low light almost dark area so that you can see the sparks coming off. If they look like a sparkler, then you have a high carbon steel, if they are small round sparks then it is low carbon. You can you tube the different sparks produced by different steel types or look it up in an old industrial arts book or blacksmiths book.
My dad just used to make new blade tips, using the machine shop ( and getting the crew to make him a stack of a few dozen at a time when they were idle) at his office, and just used to bolt on new tips when the old ones wore out. Basically a triangular shaped steel strip, sharpened along the diagonal and with a M8 hole in the end. They would last around 3 months in summer when the grass was growing fast, so we would use a round 3 sets a year, on average. Our yard had both a good collection of pebbles, and as well Turpentine nuts, which are also hard. The tips were bolted to the old blade, cut short, and just snugged up with a M8 bolt and nylock nut so they could turn with force. Bolt would last about 3 sets of blades before you had to cut it off as it was worn round. Steel for the blades was whatever scrap steel the shop had, typically offcuts from repairing trailer floors, made from 5mm steel alloy sheet.
Straight out of the box I run the cutting edge right up to the spindle cup. This does two things, 1) provides more air velocity for grass blade lifting action without modifying the wing and 2) provides more cutting surface for faster ground speed. I have a blade balancer for keeping blades balanced (simple stepped cone on a point). I do all my initial cutting edge mods on a Bridgeport mill (set a stop for fast, precise repeat-ability and fast metal removal). Mower is a John Deere 755 with a 60'' deck.
I love this guy. He seems very honest
What I was able to find out when I was trying to research mower blades is that they are made from a carbon steel and hardened to 38-42 Rockwell. It's probably made out of similar material as leaf springs. Carbon steel nickel alloy for resistance to wear. You don't want blades that are too hard because of fracturing and having the possibility of fragging anything around the mower. Mower blades are made to dent and bend on impact of hard objects like rocks. I'm pretty sure they heat treat them in a salt bath too to keep the blades from warping during the heat treat. If you'd like to try a steel with high wear resistance I would choose something that could be case hardened while maintaining the ductility of the steel. 5160 might have the properties you need.
Thanks, I may try that. Wanna see how these hold up first.....
@Cyclone Bravo Would it not work say to heat the cutting blade to black/blue hue and quench in old engine oil to harden not to hot as to make it to brittle ?
Hey Jim, nice project. The "lift" or fan blade effect isn't necessarily for grass catching bags or even for moving the cut clippings out of a chute. The blades actually "pull" the grass up so the cutting edge can get a clean cut. Without them the grass would just fall over and you will be making crop circles. Enjoyed the show.
Smarter every day has a great video on this ruclips.net/video/-GlJFVTzEsI/видео.html
I just watched the smarter every day video. That was pretty cool. Wish I had a high speed camera to use. My head is full of some crazy videos......
I feel you on the cost. Welder/FAB man here as well. Back in '99 I bought my first finish mower.. 5ft RHINO. First thing I did..removed the blades, so I could 1: Add anti seize to the threaded bolts 2: cut 1 inch away from the front ( now this is a common practice on new mowing decks..) 3: I did a grind test on 1 of the blades..yep they were cold roll. Thus I brought them to a slow heat to just were you can see the red start..then focused on the edge that would be sharpened. Got that bright red a few times hardened it out. Now keep in mind that was summer of 1998. I am about to replace those blades at the end of this summer. obtw.. This mowed is used on several 5 acre plots as well I raise it to do light bush hogging on the garden.
I have been replacing the outboard 6" of metal with 1/4" mild steel, bending a wing, and sharpening it. Has worked well for me lasting longer than a factory blade. Yes I am an experienced welder and have 62 years of welding experience. I weld them with a MIG after clamping to a piece of 1/2" metal for alignment, deep V groove the abutting pieces, weld them and flip it to other side for repeat. So far I have been successful with balance. Test each one with a pin horizontal in vise and hanging blade on it.
For Jim; wings will be necessary to create enough wind to clear clippings from under deck.
Yes, I live in a sandbed also.
GOOD LUCK!
Back it the day they made these just as you did,I Have seen many old push mowers with no lift blades .. AWESOME share ! Enjoyed ..
I have made blades from truck leaf springs in the past, they will chop through flints without too much damage, I have also built up old mower blades with face hardening rods with a fair success.
This is one of the best videos, you are very gifted engineer
A long time ago we had a lawnmower that had sickle sections riveted on the ends of the blade. When to dull to cut put new sections on. Thanks for the videos.
I work at Fisher Barton blades in Watertown Wisconsin from start to finish is really a process making lawnmower blades
most mower blades i have seen have a unique center hole that is not easily duplicated in the home shop. i have never known anyone that used up mower blades that quickly, thats some tough grass you have there.. i remember reading once that the bend plays and important role in lifting the grass to be cut. it should be interesting to see how that flat blade works for you.keep us posted.
Pensacola bahia is pretty tough, but it is the Fl sand that is killing the blades. Thanks for watching.
If you don't put on the lift you can sharpen the backside and flip the blade for another cycle
Looking forward to the test results. I have a similar problem here in SE Arizona. I only mow during monsoon season as that's the only time anything grows here; mostly weeds with stalks tough as irrigation pipe. Our soil type is basically sandblast grit so blades don't last long at all.
Hi Jim, I cured my blade problems by grinding a cutting edge full length on 2 high speed steel parting tools and then silver soldering them into a stock blade body. I am only doing about 3/4 acre with a honda hand mower but they last about 4 seasons on one sharpening.
Flat blades will not lift the grass. The ends of the blades are bent up to create lift. Nice vid. Thanks for posting.
Great project my friend, can’t wait to watch the other videos on the blades. I’m glad I saw your channel.
I used to sharpen lawnmower blades for a living. I serviced the equipment I was using. I used a 6 inch grinding wheel. It hollow grinds the blade giving it more life. I had spare blades and would check to see if the blade was dulled. I know it's just a mower blade, but when people are paying you, you want to give the them what they're paying for. The tip of the blade travels at 200 MPH, when it's dull it frays the blade of grass and opens the door for decease. And now that you're bored, after it's ground, it has to be balanced. They sell the lawn mower blade Balancers for 6 bucks at the home depot.
If you used to sharpen blades for a living, you will know you dont absolutely need a blade balancer.
a nail would do
Or a pencil
Thanks for the video, Jim. Great meeting you at the Bar-Z. Jon
From my experiences, will depend on who made the blades as to the alloy. As been recommended several times already, hardface the ground cutting edge then do a final sharpen on the mild steel and it seems to hold up well. The wear on your old blades is more so on the lift wings and that is typical of mowing sandy soil (probably like what you have in FL). I think you'll find you'll want some lift wings to aid standing the grass back up after it's under the mower deck or it will look more like you cut it with a rough cut mower. Keep the lift wing angle low and it will hold up better. Hope this helps, enjoyed the video. Look forward to see more.
Nice work there Sir Jim! Looks like they should cut well. Looking forward to the follow up video. Thanks for sharing.
Thanks, Yves!
Never made blades. but have MIG welded A36 steel strip 'wings' on the trailing edges for increased lift. Works well.
Try 1045, heat treat to Rc50, temper/draw to Rc35 or so. Works for me . Lasts a bit more than twice as long as factory stock. Buy it in 10ft sticks and the cost savings are substantial. Have had no breakage or bending issues yet!
Thanks for the info.
good thinking
Just a thought. If the cutting edge does not hold up try to weld it with a hard face rod. Just my 2 cents.
I'm only three minutes in with this comment. I did once take my LH turning Simplicity blades and put replaceable knives from a discbine onto the ends of them. I bored holes in the end of the shortened blades to fit a stack of 3/8 lock washers (for a bearing surface) and used 3/8 grade 8 bolts for an axle. Worked great!! Got me out from under buying Hi dollar Simplicity blades. I gotta wonder about the hardness of your homemade blades, but as I said,I'm only three minutes into the vid.
Try hard facing the wear spots. That happens mowing sand....Balance the blades, makes the quill last longer.
The company I work for does rough mowing with a bunch of different mowers. Flail, hammer and knife, Bush hog type rotarys and multi blade units like yours. We often end up mowing broken concrete, bricks and other trash dumped in these fields. Even 1" thick hog blades don't hold up well to that kind of abuse. I have had good results with making blades from plow steel and abrasive plate. The plow steel is a cheaper 1045 hot rolled product, and I believe the abrasive plate is AR400 or AR 450 We get drops that are not always marked properly. The best thing was to rough grind them, then throw a bead of Stoody 31 hardfacing rod on the edge before doing the finish grind. They outlast the stock blades at least 3 to 1. Now the issue is mower deck wear.
My grandpa, would use hard face rod and build up the cutting edge, lift, and mower body. . Crosshatch on the mower body and the drag rails. My grandpa was one of the owners of McKee & Hamilton in Richmond, California. Machinist, Welder, Heavy equipment repair. He ended up the superintendent of the machine shop at Kaiser shipyard #2 in Richmond by 1945 -- not to shabby from being a mechanical/blacksmith/machinist in 1939 in western Nebraska.
We use truck spring steel. Welded into the cutting edge of bushhog blades. Local place makes them up. And will out last 4 sets of store bought blades.
Damn good info buddy!
For the ultimate I would think something like S7 shock resistant steel would work great. Probably cost prohibitive though.
I second on the abrasion resist steel. My dixie chopper uses blades a full 1/4" thick. The OEM blades hold up well in the Fl sand
Thanks
Arizona here,try to keep a couple of sets handy, before they get to worn,build up, hard face sharpen and balance.or make a plate and do as suggested and use windrower blades
I did this for an old mower that they don't make blades for anymore. But I used a rosebud torch and heated the steel and hardened the cutting and lift area and it made a big difference with wear because hardened steel doesn't wear as fast as soft steel
Good vid love the iron worker.what a workshop.
I had a friend who made his blades some 40 + years ago I don't know what metal he used but they did work good
I agree with the others who suggested hard facing, I don’t know what that greens stuff is that they call grass. We don’t grow much of it around here, we can’t drill wells and the water prices are WAY to high to think of watering a lawn
It rains here sometimes twice a day, the grass grows like mad. Hardfacing won't fix what wears out, plus it's expensive as frig.....
I had just made some mild steel mower blades so far so good
Hey Jim, most blades are a steel tungsten alloy. When I make a blade I usually use a hard surfacing rod with a stick welder on the cutting edge then do the final sharpening
exactly what I expected to comment, you can use mild steel for the blade fabrication and leave a provision for applying a hardfacing bead at the cutting edge and there a huge choice of alloys to do the cutting edge
I have thought about making my own blades too. If I do, I would use the blades from a disc hay mower on the end or rivet on sickle sections so they would be replaceable cutting edges. It will be interesting to see if mild steel works and if you need to bend any lift into the blades.
just a thought at one time I believe it was lawnboy used a disc with 4 replaceable blades. thinking it may be interesting to study a haybine and see how it could be adapted. great video's Dave
Thanks for your help.is your.pull.behind mower PTO drivven to get to the point most of the blades are 1/8 the inch shorter than than the cutting number of the mower pan I use a high lift blade on my snapper 28 inch hi vac then on my Husqvarna AWD mower i use a 5 or 6 point star blade the only thing is if it is not put on the right way ooops to the adapter I have to start over again plus the blade is not as thick as it should be also it has very little lift but I think it's a great idea you g
Have making your own blades
nice project,, give us a follow up on the performance of your blades ,, thanks ,,
Hi, Props for making blades yourself.
I recommend the following instead:
1. weld new metal onto your worn blades in the 'lift' area
2. case harden the blades to resist wear
Looks like a money saving project and if they give satisfactory service, you could easily make a dozen at a time. I hit a tree root with my mower and bent the end up. It did not act like mild steel when I straightened it. Try bending an old blade to see what experience you have. It appears you might be cutting over sandy soil or mowing the edge of a gravel road to wear blades that excessively. If so, you may also eventually "sand blast" through your deck.
I have replaced conventional mower blades , with a disc .your farm store will sell you short swinging knives made for various disc type hay cutters. they also sell the pivot bushings and bolts . the knives are made in both right and left hand rotation. the knives can be flipped over as they are sharp on two sides. I mow saplings and anthills under the electric fence. I find a swinging knife to run smoother in rough cutting
The best steel to be used is carbon steel as mentioned mild steel tends to bend when hitting stuff in grass like sticks rocks if over grown i have done it with push mower it goes out of balance and destroyed the mower
I like the hard face idea for the cutting edge that Steven had. I would ad that if you don't need the lift then don't put it on. The lift creates vacuum. That's what lifts the sand into the cutting deck. The lift is destroying itself with its own function. So unless you're real particular about the cut I would try it without. I think you will find your blades will last a lot longer. If you're just doing a fields to keep the skeeters down you won't miss it.
I use mild steel for all my brushhog blades. Have done it for years. But balance is key for a mower. I also have a swisher 60" pull behind mower trail cutter. I use gator blades on it yes 20 each but I get about a year out of a set.
Jim, If you are not going bend the life edge of the blade then grind the edge on both sides of the blades so you you can flip them over and extend the cut..
Ok, nice layout, Balance? Lets see how they work.
I have a very small lawn and a small Chinese hover mower. It takes three 2 inch plastic blades which mount on three capstans underneath. They are expensive and last no time at all. I now make my own blades out of four inch lengths of coat hanger wire which I bend in half and then twist around the capstans using vise grips. They are not sharpened at all. They cut the grass perfectly well and mulch the clippings. They do wear out becoming shorter and break if you hit stones but they cost nothing and are easy to make.
Jim. With your blades I would make a round permanent centre part and rivet seven inch long 'mini blades' to it with two rivets apiece one inch apart. This should be easier to balance and less wasteful. The round centrepart could have fins like my hover mower does instead of your wings.
Deere blades(not the cheap lowes/home depot versions) are a high boron and high maganese special steel. I believe they get it from Theysenkrupp. If you want to send me the dimensions on yours I can see if they have anything you could maybe modify to work.
Thanks Brian, I'll let you know.
Interesting video excited to see how they work. Did you think about using an old leafspring?
Great idea Jim, but there are some considerations in any blade design, etc.. Right off the bat, there's something wrong. But I'll get to that later.
First off, deck blades used in 42 to 72 inch decks are pretty wide as you have discovered. They have to be able to be lightweight and aerodynamically efficient while maintaining some durability. I say some because safety is the overall consideration.
You are correct, almost all blade manufactures in the aftermarket use mild steel. These can withstand moderate temperatures and intentionally deform as necessary in the tight confines of the deck.
Using a heavier and stronger steel is possible - but at the sacrifice of requiring more power (grip) around the spindle pulley belt(s) to make sure they do not slip. Some blades require a lot of torque to get through the grass (thin, thick, tall, moisture content, etc). which means the belt and pulley system needs to be strong enough (5/8" instead of 1/2", different V-Belt angles, size of pulley's and Idlers to maintain tension, etc.), all the while trying to use as little horsepower and maintain a constant RPM for the blade design. Running the blades too fast; the aerodynamic effect will allow the grass to simply bend. Too slow, it will only cut some of the grass and begin to clog up the deck walls (in a hurry).
This leads to the 'lift' element of the blade design. It's critical or the blade will not work very well in most deck designs. The goal is based on the pure physical laws of aerodynamics. Suck the grass upwards so that as the blade swings around it's ready to cut. Without any lift, a lot of the grass will probably just bend over and only be partially cut - if at all.
There are different types of lift designs used depending on how thick the grass is and what type, and time of season (spring, summer, fall, dry or humid) and environment (cold, hot, wet) for discharge, mulch, etc.
The angle of the cut does make some difference depending on how thick the grass is. Most blades are designed between 33 and 45 degrees with the most common being between 30 and 35 degrees.
Do not attempt to heat treat or harden the blades. Should you hit an object, it could shatter the blade and create a projectile strong enough to slice through your mower's deck. Seen it happen. The blades are designed to spin up to 18,000 - 19,000 surface feet per minute. This is the speed of the tip of the blades that can be reached - which is the maximum allowed under most safety laws across North America (i.e. OSHA). The wider the blade, the faster the tip of the blade is moving. It can get ugly in a real hurry....
With no lift on your blade design, you will easily exceed this (speed) limit because there is no aerodynamic drag and would be very dangerous. The trick to maintaining lawn blades is the quality of the steel, lift design and ensuring your pulley system is in good running order. Given the number of times you cut your grass and the size of your acreage, I would test a number of different types of blades and then once you find one that is suitable, buy them in bulk. The key to keeping them sharp is making sure all edges are straight and no nicks are found on the cutting edge, side (tip) of blades AND the lift edge (top).
I suspect your mower deck (which you describe as a pull behind) is running far too fast a SFPM and the key reason your blades are being destroyed. The primary drive pulley that runs between the deck engine or PTO, should be 1:1 RPM. As you already know, PTO's are available in 6 spline 540 RPM and 20 or 21 splines for 1,000 RPM. The main pulley now has to be matched to all the Spindle Pulley's (Diameter) to ensure it is running at the right speed. If the pulley's have been changed and incorrectly replaced, that would explain a great deal why your blades are destroyed after 4 cuts per month.
If the deck has its own engine, make sure it is running at the proper RPM (maximum 3,200 - 3,300 RPM in most cases regardless if it's a Single or V-Twin).
Send me a PM if you have any questions (We've talked before).
Good luck!
Wow! Thanks for all that info. That was great. My tractor is turning slightly under the 540 pto rpms because I keep the throttle back just a bit. Everything is stock. What folks are not catching on to, the problem isn't the cutting surface, but the lift where the sand contacts the "ranp" part of the lift. It literally sand blasts the blade away. So far the blades have worked better than expected ( blades #2 is being edited now.) Still more work to do, so far it's not to bad. Thanks for watching.
Oh and the total blade length is 20 1/2".
Also ebay high lift blades made by rotary and Oregon run about 30-50 a set.
I spoke with Rotarys engineering department. They don't make anything that will work. The blades have a Kubota number stamped in them, but that doesn't help ...
There just an odd size.
A number of machinist friends of mine would call dykem DICKEM. The metal used in lawn mower blades is just what you have mild steel. This is to make sure that a blade will self destruct and not shatter on heavy impact. The newer blades are using a tougher alloy steel. But be careful fella, getting hurt in an easy thing to do.
Was that a Randy Richards scribe I saw? Looks just like mine!
It was! I love mine.
What if you used some hard surfacing or abrasion resistance rod to cut down on wear
Some of the videos I’ve watched of amateur smiths trying to make knives out of lawnmower blades speculate that they are a low grade of spring steel. They seem to be able to be hardened some but not a lot and share some similarities to leaf springs in spark testing but not quite the same. Not sure if this helps, wish I knew something firsthand to share.
What I've found so far, is that different runs of blades (even from the same manufacturer) seem to differ in material hardness. which make me think the use what they can get a good deal on.
Nice job Jim
Hello . Try to install a used piece of saw blade at the bottom of the grind. nice video . 👍
Nice video I'm going to start to make my own blade out of hardened steel wish me luck
An Aussie friend of mine had to keep the grass down short around his place, something to do with state law and wild fire management. Couple of sheep and a goat. Turned his time mowing into tucker, as he said.
lol.
Also get to eat the mower at the end of the season
I think you might be onto something, that lift creates a vacuum to pull up the grass but it also probably pulls up rocks and dirt, thus shortening the life of the blade, also be kind of cool to make blades out of an iron that you can flame harden.
Is there a link on how to put the bend in to get the correct angle ?
If you want to make your blades last a lot longer, go to a welding supply shop and pick up a can of hardening compound (arsenic, I think), get the cutting edges red hot and sprinkle the compound liberally over both sides of the cutting edge. You should easily get about 8 times the longevity out of your homemade blades. Try it, it totally works! :)
My dad used to make them from car leaf springs.
Cant believe someone has not commented on flame hardening or welding on some high carbon steel! but only if it is your scrap bin!
I was thinking the same, why not forge heat and oil quench, works on forged in fire stuff.
Did you balance the blade? If not you will be taking spindle bearings rather quickly.
have you thought of the spring steal from leaf springs from junked cars?
U must mow a lot to go true a set of blades a mounth. I mow a 5 aker yard and my blades last 2 years.
U are definitely doing a lot of cutting.
Cool. If they can work well without the lift bent into em maybe sharpening both sides? Get a swap then sharpen both edges
I was thinking the same thing!
Hey Jim Check out Meg-Mo systems. It might be just what you’re looking for. I’m not affiliated with them. I’m just tired of paying outrageous prices for blades. You could make a two blade version easy enough. But I like the idea of four per spindle to reduce wear/blade change interval.
Enjoyed the video! New subscriber!
I am pretty sure most lawn mower blades are made of mid or high carbon steel. Like 1045 and heat treated and tempered to a hardness of 40-45C. Heat treated 1045 would work quite a bit better in your application i would think.
Love the channel. How about hard facing the cutting edge?
The cutting edge is't what I'm having problems with.....It's that stupid lift.
Do you really need a 6 inch cutting edge? I thought it was only the tip of the blade that di the work? Would be interesting to do a trial....
Try drilling a hole in one of the old blade. This my give you some insights about the materialI the blades are made of . I need to make the center hole bigger in a new blade for my grandfather this blade work Hardened every quickly an I had to drill it from both sides .so my suggestion on material is something that work hardened T1 or weldox
are you mowing grass or gravel ? nice video . thanks for uploading .
Thank you for watching.
Awesome! I saw all three videos. How or where did you acquire the flat bars you claim it’s $3 a blade? Thanks
Robin Renzetti uses HSS, silver soldered to the blade.
Yep I saw that. It doesn't fix my problem though. The lift wears out way before the cutting edge.
Jim now you got to make a follow-up vid to let us know how your DIY blades did.
Oh, I see more than one video in the future...
You don't harden the cutting adge?
The mower wheels and rollers on the deck lay the grass down. The lift part of the blades are there to lift the grass up so the cutting edge can do its job correctly. The discharge coming out from under the deck is created by the lift of the blades. The lift creates an updraft that must find an escape route from the area above the blades . That up draft causes the grass to stand back up to be cut . If your blades are wearing out at the lift area, you have your deck to close to the ground and lifting grit along with the grass . Raise that deck a little and make your grass healthier and your blades last much longer. Fab Tech Tom
Jim it may be presumptuous did you balance the blades? I don’t have the same problem, however I keep 2 sets of blades for my mower. Change then sharpen, all I use is a screw in a post where my outside grinder is. You can do the same with a 1/4 rod clamped in a vice. This is one of the first things my Dad taught me in fact stressed that to me.
Another thing is I’ve shown this, I have an inexpensive flea market vice mounted outside of my shop just for those messy jobs. Mainly for knocking rust off of stock. Enjoy your videos
You could run some harden beads across the edge and regrind to slow wear. Use some electrodes take the flux off and tig it on if you dont have anything else.
The lift already wears LOOOONG before the cutting edge....The (real problem) is the soaking Kubota is giving me on the cost.
@@DoRiteFabrication maybe give them a hard coat too? Just throwing out ideas.
Can we get an update video please 🙏
I make my own. Same bar stock. But even cross marking them to center the hole is close. You'll probably still get vibration. I balance mine . Hard tipped point, on a ridged bench.. find center , (takes a bit of time) . Hold it and tap the bar to center mark the hole.
No real vibration problems yet, keep in mind the mower is WELL used.
@@DoRiteFabrication id say your sheet metal deck is more ridged than a common staped deck.
My cousin would heat them up and hammer the wings flat.
It cuts fine and is easier on the mower.
Seeing your video I am going to try a set of flat blades.
It's like bush hogging. But I have seen where mulching blades were better used on tall grass Becouse of it wrapping around mandels.
Nice..what type of Osborn wheel did you use ??? Thanks.
It was a 4 1/2" 40 grit zirconia flap wheel. I'm away from the shop, but PM me if you are interested and I'll get you a part number. They worked awesome.
Thanks so much for the info. I'll check into it. Love the channel.
Just wondering what you are putting through your mower to destroy the blades like that, other than grass??
Yes please do a follow up video.
Already have filmed #2 and hopefully will film #3 next week. You won't believe the results.
I see lots of comments about using hard facing rods. Those suckers are expensive!
I make knife blades outa lawnmower blades they do temper nicely. you maybe around 1045 maybe on commercial blades
Make sure your kids are no where around when you use that. Just incase something breaks and fly's out of there. I had an edger blade break and stuck in a tree right next to where I was standing, when someone else was using it.
I remember when i was a kid, the blade broke on my old mans mower and he only found half of it, made you think if some one was near at the time because we used to like towels through the cut wash.
Beautiful hole at 4:46 LOL see ya around
most blades are hardened just make sure you balance them and you will be fine you can use a point in the hole to get even balance its not hard to do
Gotta be careful of hardness, want them to bend, not break.
I tried modifying a blade and it cost a couple of drills and an end mill.
once i hit a rock and crack a blade , tried to weld it up whit 7018 and didint work , it was hi carbon steel an just always cracked the weld .
Invest in an inexpensive blade balancer. Its nothing more than a tapered top with steps and a point in the middle to allow the blade to tip.
Additional Comments:
One piece blades should never be made out of hi-carbon, alloy or tool steels. Once heat treated they do not have the ability to absorb shocks from high speed impacts. Two piece pivoting blades that are found on commercial mowers (bush-hogs / bat-wings) are able to use blades made from higher carbon steels. Retention of a good cutting edge requires a hardness of around HRc 52 based on application. OEM mower blades have a hardness of about HRc 38 due to the boron steels (cold rolled 10Bxx) and the austempered heat treat used to harden the blade for ductility. A differential heat treat process has been used in production where only the cutting edge of the blade was heated using an induction power supply, quenching in place with a polymer (water base) quench and the entire blade tempered at around 300'F. This process increased the hardness in the cutting edge increasing the intervals between sharpening. Some of the cladding processes of the edge mentioned in the comments could work. Care must be used to prevent tempering (lowering HRc harness) behind the cutting edge. Some type of heat sink (water cooled) could be made to control the affected heat zone
Thank you for the answer.
Nice work on the blades. Yes I agree with you. They charge to much for blades nowadays.
another option on the blades is cut 3 steel discs and bit blades from a agricultural hay cutter the disc just need to be the diameter of the old blade less the lenght of the bolt on blades that way they are easyer and cheaper to replace and because of the bolt on blade swing they break less there is also the option of fitting 3 blades per disc to speed up cutting
You mean like a hay-bine? I was considering that.
@@DoRiteFabrication yes you just need to use the proper blade bolts to let the blades spin back if they hit something
Meg Mo is a commercially built blade system that essentially does that but I don't think they use off the shelf disk mower blades. Jim could easily build his own disks to use disk mower blades that are only a couple bucks each to replace.
www.meg-mo.com/meg-mo-blades/