Carbide Indexable Vertical Shear Tool for Hard to Finish Materials
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- Опубликовано: 16 сен 2024
- This was a quick project to convert an existing lathe cutter to work double duty as a vertical shear cutter to put a final finish on hard to work materials.
Links to Tubal Cains Videos:
• SHOP TIPS #186 Vertica...
• SHOP TIPS #187 Vertica...
Please Note: I am a beginning machinist and I do not pretend to know everything. Please always operate machinery in a safe manner and if you don't know, find a reliable source. DO NOT COPY ME. I make a lot of mistakes. I provide these videos for entertainment only.
Apparently most people using cold rolled mild steel have forgotten the basics of metal removal for finishing.
If you want to get a finish that is akin to a chrome plated finish......on cold rolled or bright mild steel here is the way that I learned 60 + years ago as an apprentice.
Use a flat fronted tool like a parting tool in shape but broader with a 20 deg top rake ....possibly 6mm wide with the corners honed to a small radius to prevent tool marks...... and run the lathe slow about 50 rpm for a 50mm diam WITH COOLANT and a fairly fast feed.....you don't need a slow feed as the tool is scraping the cut on a broad front and means you can feed much faster to compensate for the slow rpm.
Depth of cut is shallow, about .05mm or .002"
The tool MUST be dead square to the work piece or you'll get a spiral like tool mark and on center so that it's cutting on the full face of the tool.
The slow rpm is the secret and this can be used on aluminium, brass and copper too.....copper works very well.
It's only used for the final finish cut where you want to have a bright chrome plated finish and a diamond honed carbide grooving tool will last forever.
That is a really interesting approach that I have never heard of. Thank you very much for sharing it. I am sure you are helping more than just me.
I took a boring bar with a triangle tip oriented similar to your tool and by rotating the bar in the holder to get the tip a few degrees off vertical I have a very good shear tool.
I like it. Does it stay in position well?
@@DudleyToolwright Yea, it's locked in with all 4 set screws in the tool holder. I suppose an actual boring bar holder would be more secure, but doesn't seem necessary. I tried it tonight, must have been hot rolled bar. Couldn't get the mirror finish I got on cold rolled, but still pretty good. Tried some different angles. Seems like not far off vertical is the best. Is that your experience too?
I like your videos. Cold rolled steel is gummy. It likes a lot of speed and feed. Finish cuts should be with a small radius positive rake tool. The passes I watched were tearing the material off not cutting it off. Surface speed should be at least 750. That is not rpm. To determine RPM multiply SFM by 3.8197 then divide by material diamiter. Example: 2 1/2 inch dia. material; 750 sfm X 3.8197= 2864.775 divided by 2.5 = 1145.9 RPM . Select closest RPM on your lathe and Rough turn with a .015 feed or more .05 depth of cut, or more. Then finish feed at .007 or less. If your finish is still poor speed it up. I recomend a coolant be used also. You should be able to find a coolant mister, air powered, online or make one easily and you can turn and mill with it.
Thanks for the tips. I really appreciate you taking the time to suggest improvements. I will definitely try out your suggestions. I have only recently been trying to push my feed rates and have been very surprised with the results. Cheers.
Dudley Toolwright
This is very good. Well worth the experimentation and nice results. Like to try this without changing the Holder but using the same insert in the vertical plane. We got nothing to lose and need not follow old school machinist's conventions.
Thanks for sharing
aRM
I am interested to know how well perpendicular works. My approach made trying multiple angles difficult.
I like that you can still use the holder for it's original intended purpose. Now it does 2 jobs. Nice
I like multipurpose tools as well as long as they don't sacrifice too much functionality. I would love a Leatherman if I was stuck on a desert island, but for daily use, bleck!
You don’t need HSS, however it will work really well with a good grind. However, once you get to know the material, and tooling, you can create a very good finish with indexables. Rough with neg rake WNMG, finish .01-0.02 with pos rake high speed as I already mentioned in a previous post. On the cnc, 1000 SFPM for mild steel, mirror finish, it burnishes as it cuts. Home lathe 600-800 SFPM, it just whips chips across the garage, good to get a guard for some of that nonsense.
Happy steel whittling
Thanks for the really helpful suggestions. I always love to learn something new.
Very cool idea , that stuff is hard to turn !
Thanks. I appreciate the comments and nothing is more irritating than a bad finish, except maybe a bad fit. Cheers.
Very nice solves a number of problems with brass for my tool making
I am glad you found the information useful.
Thanks for the video! Never thought about using Carbide for this.
Thanks, I hope it works out for you.
.003 to .007 cut and skip the lube and if using the carbide take a diamond to the edge there is a super small radius on the edges on all inserts or use a insert seat as the cutter thats what they used at TRW they used a square insert seat in a positive rake holder set in sideways cut like butter the cause a seat is shaper. thanks for sharing
Thanks for taking the time to share some suggestions. I really appreciate it.
I use a boring bar... it's round so you can set any angle you want.
That is a really interesting approach. It make complete sense and is quite a bit more versatile. Thanks for taking the time to share that idea.
I’ll definitely be trying this one. Thanks for posting!
Let me know how you like it.
High speed steel will work a lot better and will probably leave an even better finish as carbide insert edges are not sharp. They usually are chamfered, rounded, eliptical with specific proportions or something proprietary. If you grind carbide to sharp point it will work but the sharp edge will deteriorate far quicker than if it was HSS.
Good to know. I haven't tried HSS, but this carbide is pretty sharp along the edge. I appreciate the input.
Dudley Toolwright if you try HSS use round stock rather than square that way you can easily alter the angle to experiment for best results. If you do add a little top (?) rake you will get better results.
Hi Nice tool, a good old handmade thumbs up to you, BTW many thanks for interesting videos please keep them comming.
My pleasure and thanks for watching.
Been there ,Done that. But I got an even better finish with a 15 degrees off of horizontal
Very interesting. Thanks for the tip.
You can take a round boring bar and rotate it in the holder and get a shear tool...
Great observation. I had not considered that option. Thanks for sharing.
I really like how you explain everything, and I really enjoy watching your videos. Now I’m thinking to get in to metal work, can you make video talking about your equipment and what it cost? Thanks.
Thanks. I appreciate to comments and you watching. A guy that is a true pro, unlike myself, is Tom Lipton. I highly recommend his channel. He is a way above average, career machinist, who explains his thinking at every step. I only hope to get my channel to his level. I would be happy to talk about my equipment, but I have a very understanding wife who supports my crazy hobby. as a result my mill and lathe were purchased new - not something that everyone can afford. There is a ton of high quality used equipment out there for a tiny fraction of the cost of new. I just wasn't that bold. I was afraid that I would ignorantly get a machine like the beat up ones at the adult school where I took classes in machining. Combine that with impatience and you have a recipe for serious money expenditure. I love precision more than almost anything and didn't want to risk have the machine be the limiting factor instead of my poor skills. So I bought new. If I had it to do over, I would take a good long look at used equipment. The mill is an ACRA 9x49, Chinese made (their first Chinese machine), and was about $5000. The lathe was an ACRA Heavy 14, made in Taiwan, and was $11000. I love both of these machines and treat them a lot like other guys treat their cars. I never end a day of use without cleaning them completely and always keep them lubricated. I am so paranoid, that I have never used the coolant, because I am afraid of rust.I highly recommend getting into machining. It is a game of constant problem solving. So, if you enjoy that sort of thing, you might have found the right past time. Order of operations and clamping methods are different almost every time and often critical to a good outcome. There are a million tricks and even more tools. as a matter of fact, you will probably end up spending more on tooling in the long run than you do on the machines themselves. Especially, if you are like me and never saw a decent tool that you didn't want to have.
Dudley Toolwright . Very good demo . I have tried this many years ago with brazed /silver solder carbide tips . my results were not that good as I was using old carbide tips and grinding them to make a shear tool . my best efforts were with tool steel , not the chineesium cheap stuff ,British made branded tool steel from the 1970s
The biggest satisfaction I get is making and using most of my own tooling holders and jigs , I am now retired (or should that be ''retarded'' ) as I only do machining now that I see as unusual or a challenge , mainly farm fit repair items where not much great accuracy is needed apart from bearing or bushing fits .This is the home workshop where jobs finish up when no one else wants to do them .
Christopher C. Are you in the UK?
HSS would be much better for this, mr pete has an excellent video (or two?) on them. it looks like the carbide is still mostly rubbing
Interesting feedback thanks. I have had really go luck with carbide. I think that unless you need the toughness of HSS, carbide can be as sharp and hold the edge better - except for interrupted cuts. Judy a novices's opinion.
@@DudleyToolwright carbine will never hold a sharp edge as well as HSS because it is orders of magnitude harder and therefore more brittle. it might seem like it's holding an edge longer but in reality it's micro-fracturing and abrading away tiny amounts at a time. there is a reason carbide inserts have radiuses ground on them, because if they didn't, they'd make their own random radius in short order. that is why carbide has a minimum surface speed and depth of cut it likes to be run at for a given geometry, and HSS is far more tolerant to that, because carbide is worse at shearing, especially small depths of cut. it will often end up trying to self feed, which is what the occasional random squeak and streak is while you're taking tiny cuts with it.
if i need to sneak up on a precise diameter, i will switch out from carbide to a HSS vertical shear tool
Very interesting thanks. I will obviously need to investigate further. I appreciate you sharing that info.
@@DudleyToolwright any time. i am still an apprentice but i like to help how i can
Well thanks. I know your time is valuable.
Another option for those huge toolholders is to cut an Aloris dovetail in the tooholder itself.
Very true. A built in dovetail can make for a very flexible tool. I might want to try a vertical shear cutter like this with the added option of adjustable shear angle. Thanks as always.
There's at least one older YT video showing high magnification shots of the cutting action in slow motion. Damned if I can remember the name of the video though. Anyway it shows the material building up on the tool tip and that material pushes more metal off instead of cutting the material in advance of the tool tip. Once the forces get high enough the built up material then folds under the tip and the whole process starts over again. I'd be willing to bet that's what's causing those grooves in the finish you showed with the first conventional tool tip. As others have already said ultra sharp and properly honed HSS with the correct rake and clearance would do as well or better than this tool, but it was still an interesting video.
Edit, I re-found that video, check out Iscar Chip Formation .wmv Posted by Rick Steinard.
Thanks. I love the ISCAR video. Utterly mesmerizing. I also appreciate the insight as to what might be causing the grooving problems. I still have to play with HSS. I have only used it to make a trepanning cutter thus far with mixed results. I got a tone of carbide inserts at an estate sale, so I have a ton of experimenting to go there as well.
Dudley Toolwright Carbide as good as it is can't do everything. Like all machining processes it's always a series of trade offs and compromises. The newer grades micro carbide, multiple chip breaker designs and the vast number of coatings are a lot better than the much older uncoated plain grades of course. The very old high carbon grades of cutting tools can probably be sharpened a bit keener than even HSS can, but tool life at the slower speeds suitable for it are far less than a HSS edge at it's usual 100 ft. per min. on mild steel. That doesn't mean there's no place for shop built and hardened high carbon cutting tools if something special might be needed. Boring with a boring head on a mill usually can't take the high depths of cut and feeds suitable for carbide for the best surface finish since it then takes a lot more massive machine than our little Bridgeport clones are. I can and do resharpen my own HSS tool blanks, but for repeatability I sometimes also use the A.R. Warner pre formed HSS tool tips that are designed for use in the the more usual tools that take replaceable carbide cutting tool and boring bar tips. It's a whole lot easier to then sneak up on the target dimension since a good sharp HSS tool can take as little as a few thou and still cut just fine.
With my limited knowledge and understanding I think on average most carbide is meant to use high pressures and heat from the cutting process to help plasticize the metal something like that Iscar video shows. When that happens on good machinable grades of metal the surface quality goes way up. Poorer but still machinable grades of metal create that built up edge problem shown in the video. Especially so for most grades of aluminum. Obviously if the metal isn't being cleanly sheared and everything removed and flowing off the tool edge as soon as it's cut you then get that crappy surface finish. I'm certainly no expert so it's a best guess, but it's likely your shear tool is helping to prevent a lot of that built up edge and acts to wipe across the surface smoothing it off a lot better.
Proper sharpening of HSS also isn't quite as simple as it first looks. Wheel selection is extremely important. Highly experienced Woodworker types go to great lengths to get there tools ultra sharp. For that reason using the same recommendations they use for wheel selection is I think a good idea. They also won't usually use any tool with a bench grinder finish without a final stoning on one or more fine stones. Wood lathe users might be the exception. So for chisels and plane blades there honing there tools like we need to. It's impossible to get a better surface finish than the tools cutting surface is. Same thing for carbide, those green grit wheels are only meant for rough shaping, it takes a diamond wheel to get the final honed finish the tool needs for the best results. Any tool will still cut right off a bench grinder, it just won't cut as well, last as long or produce the best surface that a honed tool will.
Thank you for the very detailed explanation. You have sold me on trying HSS. I have been accumulating some and will try it out. I even have some tools that other machinists have ground. I suspect that these will be a good starting point. I really appreciate you taking the time to really flesh out your perspectives. I suspect that I am not the only one who will benefit. Very cool.
Turning Point, you talk a great deal of sense sir! Being a "Woodworking type" I could not agree more. And looking at Abom79 videos he is as passionate about getting his HSS shaper tool bits razor sharp with plenty of stoning his bits after coming off his grinder ( in fact any of his HSS bits ! Lol) i am also a woodturner using HSS turning tools and I ALWAYS use the diamond hones after regrinding my tools, it saves a LOT of metal honing that edge up to six or seven times before regrinding is required. If you saw the price of good quality HSS turning tools you will appreciate that grinding 5 to 10 thou off of them every time you needed to sharpen them by grinding them rather than honing will save you a whole lot of money.
Seeing you've had this one published for a while, ... have you tried multiple spring passes using a vertical shear? I tried it in a relief area on a chunk of "old, gummy," returning the tool to the start position without bothering to retract it and engaged the feed clutch again, until I got two passes without any form of chip being made. The last were so fine you had to lay a clean cloth down under the tool to see them ("fine as frog hair, split three ways"). Probably the best finish I've ever gotten on the Old Warrior without the use of abrasives.
I think a lot of it has to do with the tool not following the exact same path down the work from the previous pass. Any tool will leave ridges according to it's form, even if it's only at the micron level, on a single pass. Subsequent spring passes, that travel down the work along a path that is not exactly the same as the previous one, gives the tool a chance to further take down those high points.
What I'd like to see explored is the practicality of a carbide vertical shear on material that a HSS tool can't even begin to touch. Especially within the parameters of an older, larger engine lathe like mine, that was originally designed to run from a line shaft. Top spindle speeds are no where near what more modern lathes can reliably get to, and feed rates usually are not so fine. If it increases the chances of success in getting a critical dimension, and lowers the probability of overshooting tolerances, it would be worth knowing about.
I have and as you suggest, I almost always get more material removal on at least one subsequent pass. There always seems to be a bit of flex in the work piece or the tooling and, as you said, the tool never follows the exact same spiral around the work. I should try the vertical shear tool on some really hard material, it would bean interesting test. The reason I haven't tried this before, is because, hard materials always seem to cut well and leave a nice finish.
you should not need to do a "spring pass" with a vertical shear tool (or shear tool of nearly any kind- but it depends) because they exert very low pressure on the work. and in nearly any situation, should never require more than 1-2 spring passes. if you do, something else is wrong.
Curiously I'm wondering if the bar your machining is made from PM (powder metallurgy) steel vs wrought steel. If PM bars do not receive a minimum of 50% reduction during the hot forged hot rolled or hot extrusion process the material will not close up all of the internal inclusions inside the bar. The material starts out as a powder then pressed into a gross shape and than sintered at high temperatures for an extended time. That neat tip that you've come up maybe actually be smearing the metal into the and hiding the inclusions view. Just curious. Check your ASTM Specs
That was an interesting possibility, that I never considered. I know very little about powdered metal products. The only time I have ever heard of them being used is in things like inexpensive gears. I will have to go and learn more. Thanks for the tip.
I spent 20 years working with and developing PM materials in the very high-end side of the market, metal making in a test tube. It's amazing stuff. Check the ASM web site for information.
I will do that. The topic is fascinating. It probably becomes even more relevant in light of laser sintering and even carbide inserts themselves. Getting information can be tough though. ASM makes their knowledge more easily accessible to industry than to a hobbyist like myself. I really appreciate you taking the time to share.
I was just looking at an online course on Metallurgy for the non-metallurgist and it was $1400/$1200 depending on membership. Unfortunately outside my affordability window. These prices are typical for continuing education where the purveyors are expecting a company will pick up the costs.
@@DudleyToolwright im sorry i dont have a particular site or link in mind, but i know that when i took my engineering degree, i used som free online lectures/courses on that topic.
Could just be youtube, and again im sorry i dont have a link right now.
But it should be out there.
Is there a particular topic youd want to start out with?
@ 6:20 The sparks flying off your cutter made me cringe. That tool holder likely is hardened. You did not mention if the 1/2 in end mill you used was tool steel or carbide. For cold roll, tool steel is all you need, and can be easily sharpened to a sharper edge than carbide.
Thanks for the interesting observation. My end mill is carbide and the too holder seems to be hardened. Coolant would be an improvement, but I am always paranoid about corrosion.
Dudley Toolwright corrosion of what exactly?
It DOES matter where you cut, in that you should cut BELOW center, not on or above.
The closer to 90 degrees your angle is (max 85) the finer your finish.
And last but not least, HSS does a damned sight better for this than carbide does.
You can even get a decent finish on 'black pipe' in the lathe, this being the gummiest crud even devised by man and turned in a lathe!
Paddy
My apologies, I was unclear in my explanation. What I meant was, it is unimportant which part of the cutting edge you use, not where on the part it makes contact.
I have used high speed steel in the past and it can provide a better finish on cold rolled steel, but in my very limited experience, not great either. I do however, really appreciate you taking the time to share your thoughts. Thanks.
Dudley,
Well, it is important to experiment with 'feeds & speeds' .... I have had different results with the same material (according to the DIN norm, anyway...) from different manufacturers.
The main thing (and this too will depend, to an extent, on the machine you use) is a very fine feed, a decent speed and a rather shallow contact angle and of course the most shallow cut possible,. No matter what the different materials are, or what machine you use, I have found that any sin against the above will make matters worse.
You almost want 'fluffy metal wool ' (is that a real term? LOL) to come off of the workpiece. I thought your swarf (in the demo you did) was still a bit too 'chip like', meaning you cut rather than sheer.
In any case, it is a great tool to experiment with, and leave others scratching their heads, how you get such a nice finish on gummy, crappy types of steel!
Toodles!
Paddy
Thanks for all of the info. I really appreciate you taking the time to share your thoughts. I never fail to learn something. I do need to experiment more with the vertical shear cutter. I have a project coming up that is going to use some cold rolled steel, so I might get my chance..
Smaller depth of cut 1000 at time Ever turn a brake rotor Smaller slower cuts nicer finish
In my limited experience, surface finish is very material dependent. I have some materials that do extremely well with large depths of cut and high feed rates, while others do a lot better with your recommendations. Interestingly, I have never turned a brake rotor. Thanks for the suggestions, they are always appreciated.
Try running the spindle faster. 600-800 fpm. That’s 1000 rpm min for that shaft. Creates good results with conventional inserts.....usually.
Thanks for the suggestions. I really appreciate them and the time it took you to share.
Being new to all this I'm having enough trouble finding a tool holder that positions the flat of the triangle cutter parallel to the work to begin with🤔, ( 1/2 inch at that) and then cheap enough not to be hardened so my little pm25 mill can cut it. I love the idea though cause I stink at shaping hss blanks. Anyone happen to have a tool holder part # ? Thx
The one I used is a CTCPL but possibly MTFNL. This is a good site for insert and tool holder info: www.carbidedepot.com/Toolholders-C14.aspx
Nice I like it!
Thanks.
Nice thanks for sharing
Thanks for watching.
Why not just use a large radius finishing tool?
That might work as well, but the vertical shear cutter has a different cutting action and is known to work where other cutter styles will not. That being said, I am no expert and appreciate any suggestions people are willing to give.
Large radius, positive rake with very little land. I routinely used to get mirror finishes on cold rolled. 600sfm, .0111" per rev at .100 depth of cut
Your feeds and speeds are completely wrong. That's why your surface finish is that bad. You need to be at a much higher RPM for carbide inserts.
Thanks for the tips. Although once true, the high RPM requirement is no longer the universal rule for carbide. New carbide formulations and edge honing have made some carbide cutters comprable to HHS.
@@DudleyToolwright I've looked very hard for those kinds of inserts over the past few months. The only thing that comes close are finishing inserts with a wiper that specify a relatively low surface speed. But I can get a mirror finish with the average carbide insert on mild steel by running at the recommended surface speeds. Anything less and I get the same result you're getting.
Good demo video. Doubleboost has the best camera setups I've seen. He has a ceiling mount camera stand over his lathe and mill, along with great light for his close up work. He also seems to use tool post mounts, but has very little vibration, even on the tool post mounts, or at least doesn't show the video with extreme vibration. lol -
Check out this video. ruclips.net/video/SjZ694cX4QU/видео.html
Thanks. I have watched his channel before, but now I will look more closely.