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Jim2
05-23-2013, 12:55 PM
I'd been reading about the tangential lathe tool in different places on the internet, so decided to give it a try last year. Like so many others, I came up with a simple design and went for it. Here's what that looks like:

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%201/Holder-001_zpsb8935f8b.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%201/Holder-001_zpsb8935f8b.jpg.html)

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%201/Holder-003_zps5d19f030.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%201/Holder-003_zps5d19f030.jpg.html)


I was immediately impressed with the ease of sharpening and the finish that I was able to achieve with the tangential tool holder. So, I could see that it was worth the trouble. . . . But, there were a couple of problems.

1) My original design required me to make a bolt to hold the toolbit in place. I chose to put fine-thread on it thinking that it would hold the bit tighter with less effort than would be required by coarse thread. Problem was, it was easy to over-tighten and destroy the bolt

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/ToolBroken-001.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/ToolBroken-001.jpg.html)

I tried making a coarse-thread replacement, but the replacement suffered the same fate! I finally replaced with grade 8 button-head bolt, and that held. Note that I never have experienced any problems with the bit slipping down in it's slot--it was just over-torquing it that was the issue (clumsy bastard!).

2) There was not enough clearance to face large parts. The bolt that holds the toolbit does not allow for turning and facing of pieces larger than 1 1/2" or 1 3/4" without the bolt rubbing against the workpiece. This is really a show-stopper as part of the allure of the tangential toolholder is the ability to face and turn without repositioning the holder. Without this ability it will always be "less than". . . .

3) Design of toolholder will not allow it to work equally well when facing a deep slot at the "tailstock end" as it does at the "chuck end" of the work piece. There's just too much metal extending to the right of the toolbit. No getting around it with this design.

more to come!

Jim2
05-23-2013, 01:26 PM
This time 'round, I wanted to be sure that it would turn and face without any limitations from the toolbit clamping mechanism. I wanted something simple and durable in case the mechanism broke, so that it could be easily replaced. I wanted to be sure the toolbit would be held tightly in the slot. This is what I came up with:

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%202/Holder-001_zps478472db.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%202/Holder-001_zps478472db.jpg.html)

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%202/Holder-003_zpse3700819.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%202/Holder-003_zpse3700819.jpg.html)


That's a chunk of metal there--1 1/2" wide x 1 3/4 high at it's largest point. The "half-moon" holder is 1" diameter, W1 toolsteel. I figured that I could harden it if it showed any signs of wear or weakness, and it would be easy to replace. Yeah, that extra radius running vertically was a mistake. . . . I figure no reason to try to cover it up. There was plenty of metal to get the job done anyway.

This version didn't have any of the annoying problems with interference when turning and facing--no repositioning of the tool required! It might have been "good enough", but for the fact that the first thing I tried it out on was one of those dumb little projects where you do something because you can, not because it is necessarily a good idea. I needed to take a piece of 10" piece of 1/2" shaft down to 7/16". So, I get a center in the end of the piece, slide it out of the collet, tighten it up, set up the tailstock, and. . . . Whoa this toolholder is huge! Getting the tool holder even close to the live center is going to be a real pain. This is actually the moment when the third "requirement" from the other post started to form in my mind.

There has to be a better way, so it's back to Google images. . . .

Paul Alciatore
05-23-2013, 02:10 PM
...<snip>...

Yeah, that extra radius running vertically was a mistake. . . . I figure no reason to try to cover it up. There was plenty of metal to get the job done anyway.

...<snip>...

This is a very interesting thread. I have often wondered if I could make a tangential holder.

I find the remark about an "extra radius running vertically" I quoted a bit confusing. Exactly what radius are you referring to?

I also fail to see why the nose area of the holder needs to be so wide. The bit is constrained at the front by a relatively thin wedge of metal that is, perhaps 1/8" or even 1/16" thick at the top. So why is almost a full inch of metal needed to the side? It would seem that the front wedge of metal takes most of the clamping force as well as the force generated while cutting. The metal to the side of the tool would be under less stress. Perhaps this thickness to the side could be cut in half or even less. Perhaps as little as 1/4" would suffice.

Jim2
05-23-2013, 02:30 PM
There have been a couple of toolholders on other forums that I took most of my inspiration on No 3. One fellow in particular had come up with a clever way of drilling a hole in his toolholder and then silver-soldering a piece of shaft in there that had been split down it's center with a square cross-section machined into it. He had done such a nice job that it was difficult to tell how he'd made that nice square hole! Anyway, this is what I did:

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%203/Holder-011_zps798996c9.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%203/Holder-011_zps798996c9.jpg.html)

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%203/Holder-009_zps386299f3.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%203/Holder-009_zps386299f3.jpg.html)

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%203/Holder-006_zps6b70019d.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%203/Holder-006_zps6b70019d.jpg.html)

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%203/Holder-003_zps5487ee64.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%203/Holder-003_zps5487ee64.jpg.html)


I know lotsa milling marks on the toolholder. Meh, I kinda like it! I was in a class, and they had one of those triangular insert face-mills. It gets plenty of use and abuse from all of us noobs in there, so no doubt may have been cutting on just one insert? But, I was still impressed with its metal-moving capability. I don't have carbide at home, and this thing was taking off 3 times as much each pass of anything else that I had tried (toolholder is A2 toolsteel). The smooth portions of the shank were done with my 7" Porter-Cable shaper. I'm a noob on that, too. This and No 2 above were really the first times that I'd had a chance to get my feet wet with it. I have to say it's great fun for a hobbyist like me. I wouldn't want to try to make money with it, though.

I'll follow up with a drawing if anyone is curious about dimensions.

Jim

Jim2
05-23-2013, 02:38 PM
@Paul:

Yeah, it could be narrowed down a bit, no doubt. It's quite a chunk of metal. There's no reason that it has to be that thick. The reason that I designed it that way (1 1/2" wide) is so that it could be angled properly to work with my primitive, lantern-style toolpost, and still have the clearance necessary to do the turning and facing without repositioning. Stock on the right side would have to be removed to satisfy those requirements.

I'm not going to lose too much sleep over it, because No 3 is a better design, IMO.

Here's the drawing of No 3

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%203/TangentTool-002_zpsc3cf938f.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%203/TangentTool-002_zpsc3cf938f.jpg.html)

Jim

Jim2
05-23-2013, 02:53 PM
This is a very interesting thread. I have often wondered if I could make a tangential holder.

I find the remark about an "extra radius running vertically" I quoted a bit confusing. Exactly what radius are you referring to?


Thanks, Paul.

I'm referring to the radius where the narrow part of the shank meets the thicker portion. You can see it better here:

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%202/Holder-004_zps77065243.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%202/Holder-004_zps77065243.jpg.html)

It was just one of those dumb little math errors. I forgot to subtract out the radius of the hole I was drilling, but NBD in this case.

Jim

Norman Bain
05-23-2013, 04:36 PM
Jim,
In version #3 did you use a milling cutter to cut the square slot for the toolholder; or did you use the shaper?

Cheers,
Norman

Jim2
05-23-2013, 04:39 PM
I used a slitting saw to get it close, then cleaned it up with a 3/16 end mill. I'm sure the end mill would have done the whole job, no problem.

Jim

dfw5914
05-23-2013, 05:37 PM
Thanks for posting this interesting project, what drawing program are you using (for drawing in post #5)?

Johnnyreich
05-23-2013, 06:32 PM
Jim,

All of those tangential holders are awesome.

I couldn't help but notice your collet chuck. Is that one of your own creations as well? I ask because I have a Sheldon 10" lathe with a 1 3/4", 8 TPI spindle that's extremely non-standard with respect to today's available commercial tooling. I'm considering turning my own ER40 chuck and thought I'd get some advice from you or anyone else reading this post. I hope I'm not hijacking this thread.... again.... just awesome tooling on your part.

Johnny

Jim2
05-23-2013, 10:40 PM
Thanks for posting this interesting project, what drawing program are you using (for drawing in post #5)?

I'm using Google Sketchup. I never used any kind of 3D drawing program before, but the tutorials make it pretty easy to get started. I wouldn't say it's easy, but persistence seems to pay off eventually. Put it this way--the tool is capable even when the user isn't!




Jim,

All of those tangential holders are awesome.

I couldn't help but notice your collet chuck. Is that one of your own creations as well? I ask because I have a Sheldon 10" lathe with a 1 3/4", 8 TPI spindle that's extremely non-standard with respect to today's available commercial tooling. I'm considering turning my own ER40 chuck and thought I'd get some advice from you or anyone else reading this post. I hope I'm not hijacking this thread.... again.... just awesome tooling on your part.

Johnny

Yes, I did make up the collet holder for the lathe. My Leblonde is quite old, a 1924. . . . It's been a few years now since I did it. I think the taper was messed up in there. Anyway I cleaned it up a bit. It's basically a MT 5 now. It has a 1 3/8" ID spindle, so 5c works pretty well with it. The version you're looking at is actually round 2 on that as well. I made a handwheel-style tube in Round 1, and that worked pretty well. Here's a pic

http://img.photobucket.com/albums/v280/jasch/Metalworking/Collet%20Closer/Handwheel-01.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Collet%20Closer/Handwheel-01.jpg.html)


The problem with that was that the internal thread that engages the 5c collets eventually stripped out. I hadn't done many internal threads prior to making the tube, so they weren't maybe the best. Then there is the way the headstock is designed. As you can see it was difficult to get something that would accomodate the belt-drive there. At that time I didn't have the guard on the belt because the closer was in the way. It was definitely a hazard, but that end of the lathe was back in a corner--still not good. When we moved to the new house, something had to be done. The lathe was set up in the middle of a big garage, and I couldn't be sure that my kids wouldn't show up and get tangled up in that belt. Something had to be done. . . .

Please look away if cutting up classic machine tools/guards makes you queasy

http://img.photobucket.com/albums/v280/jasch/Metalworking/Collet%20Closer/IMG_3548_zps3daad645.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Collet%20Closer/IMG_3548_zps3daad645.jpg.html)


Round 2, includes the addition of the big nut on the end. I use the handwheel to engage the full length of the thread on the 5c collet, then tighten the big nut to tighten the workpiece in the collet. The handwheel is keyed to the tube, but is free to slide along it. I think this arrangement may help to preserve the lifespan of the threads. It's been working this way for me for quite some time now. Notice the extra length that will be used when those threads eventually fail on the collet end.

Jim

tlfamm
05-25-2013, 11:19 AM
Jim, #3 is a nifty design, and your implementation looks "sturdy" to put it mildly. Nicely done.


Just for the sake of discussion, could the "vise" end of the holder be reconceptualized as a two-piece affair, coupled with three or four clamping screws, thus eliminating the long slot for those without the horsepower or slotting saw to fabricate such?

adatesman
05-25-2013, 01:34 PM
Seems to me a well guided hacksaw or bandsaw would work for those of us lacking the ability to use large slotters...

Jim2
05-26-2013, 12:22 AM
Thanks, tlfamm. adatesman has it figured out. The slot doesn't need to be as wide as I made it. A hacksaw or a bandsaw would do the job just fine. For me, part of the elegance of the design is that it's all made from one piece of steel. It was also much easier to make than the other designs because it doesn't have any of those confusing compound angles.

Jim

dian
05-26-2013, 07:37 AM
how did you make the rectangular slots, the tool sits in (in the last holder)? using the shaper? but how?

Jim2
05-26-2013, 09:18 AM
No, I only used the shaper to form the shank of the tool. I used a slitting saw to rough out the spot where the bit is held, and then finished the slot off with a 3/16" end mill. As you can see there is a 5/16" hole that removes the metal for the "back corner". That was drilled first. IMO, the setups on the "No 3" tool were easier than the previous toolholders!

Could the shaper have done the tool slot? Yeah, I'm sure, but the thought never occurred to me when I was designing the tool.

Jim

customcutter
05-26-2013, 03:34 PM
Jim,

Looks good. I guess you still have the 12* front to back, but eliminated the 12* side angle? I was wondering if with the straight on angle, if the cutter would present 60*, for threading purposes. But, I'm thinking the tool would have to be ground at 18*, plus the 12* built into the tool holder, to present an effective 60* cutting tip. Or does my math still stink????

I finally built one last week and was thinking the diamond looked like a 60* when ground of at 30*. But the 12* side angle, is no good for threading, was thinking of maybe making a straight one like you did.

CC

Sun God
05-26-2013, 10:05 PM
No, it wouldn't come close to being able to thread. I did the math a while ago, and from memory you have to lay the bit down at about 63 degrees from vertical to get the 60 degree point angle, which would leave the tip of the tool seriously unsupported.

Jim2
05-26-2013, 11:24 PM
I've never considered using the tangential holders for threading, so I can't speak to that.

re: losing the 12 degree side angle--no, it's not a 12 degree angle front to back. It's 16.9 degrees front to back. I came up with the 16.9 degree angle at the front of No 3 by calculating from the drawing of No 2. So, that 12 degree side clearance is still there. No 3 is sharpened the same and holds the toolbit the same as the two previous versions. I'm presenting it to the work at a 45 degree angle. You can see this in the pictures.

Jim

vpt
05-27-2013, 07:59 AM
Nice stuff! Very well done!

Blackadder
05-27-2013, 09:37 AM
it may be of interest but the Australian version ( excentric Eng ) do supply the details on how to grind up the tool bit for threading for use in their holder its done with the same sharpening jig that they supply

Stuart

Jim2
05-27-2013, 06:49 PM
Thanks for all the nice comments.

I'll have to investigate how to grind a bit for threading. I'm kind of curious as to how that could be done.

Jim

Norman Bain
06-02-2013, 04:44 PM
I have been following the tangential tool holder thread started by Jim2. To be fair I am not sure such a tool holder would suit my uses as near everything I try to make seems to have a square shoulder and these tool holders don't work well for that purpose.

Anyways; got to thinking that the holder (generally surrounding the tool bit) could be made stronger (have more metal) if the section was created by a broach. Is the design at the nose of the holder "compromised" by the need to use a slitting saw or end mill to cut the square section?

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%203/TangentTool-002_zpsc3cf938f.jpg

Anyways; got to thinking on how to make a square broach. The use of such a broach would of course not just be limited to this purpose.

Would the following approach work to create an effective square broach:
1) Using a piece of HSS already sized to correct square section; the one in my image is 3/8" (9.525mm) x 4" long.
2) Heat it up in fire till is suitably softened and then cool slowly.
3) Put in 4-jaw in lathe and center drill ... this for later use.
4) Using mill cut the series of flats ... these will become the teeth of the broach.
5) Put back in lathe and (with tail end supported in live center) create some relief for the teeth ... essentially someplace for the chips to go.
6) Using mill cut the relief at the shank of the broach.
7) Re-harden.

To use the broach:
a) Drill hole somewhere between 8.5mm to 9mm; the cross section of tip of broach will fit in ok.
b) Push it thru.

http://downloads.purposebuilt.com.au/NJB/SquareBroach/Drawing_1.png

Cheers,
Norman

elf
06-02-2013, 04:53 PM
Would the following approach work to create an effective square broach:
1) Using a piece of HSS already sized to correct square section; the one in my image is 3/8" (9.525mm) x 4" long.
2) Heat it up in fire till is suitably softened and then cool slowly.
3) Put in 4-jaw in lathe and center drill ... this for later use.
4) Using mill cut the series of flats ... these will become the teeth of the broach.
5) Put back in lathe and (with tail end supported in live center) create some relief for the teeth ... essentially someplace for the chips to go.
6) Using mill cut the relief at the shank of the broach.
7) Re-harden.

To use the broach:
a) Drill hole somewhere between 8.5mm to 9mm; the cross section of tip of broach will fit in ok.
b) Push it thru.

Cheers,
Norman

Step 2 and 7 will fail :). Try using O-1 instead of HSS.

Elninio
06-02-2013, 05:45 PM
You have the same ammount of material holding your cutter (its symmetric) - this is bad, since cutting forces push your cutter into its seat, so you should make that side thicker to dampen vibrations more. The best method for holding flats is by clamping; the australian tool sells HSS bits with dovetails on them, which is fantastic, but since you can't have that (its hard to make, or expensive to buy), i would recommend a wedge clamping underneat the tool, like how parting blades are held by wedge: http://shopimages.toolsnz.com/TNZ00255.jpg

Paul Alciatore
06-02-2013, 11:35 PM
That 63 degree angle sounded a bit too much so I did the math. I come up with 54.74 degrees from vertical. Not as much as you stated, but still out of the ball park. Way too much clearance angle. The tip will either snap off or wear very quickly. Of course, it would work OK for machining wax.

If you are going to thread with a tangential holder, you are going to have to do some grinding on the sides or pull some other trick.


No, it wouldn't come close to being able to thread. I did the math a while ago, and from memory you have to lay the bit down at about 63 degrees from vertical to get the 60 degree point angle, which would leave the tip of the tool seriously unsupported.

adatesman
06-03-2013, 08:04 AM
Step 2 and 7 will fail :). Try using O-1 instead of HSS.

I think what Elf means is that annealing and rehardening HSS is well beyond the capabilities of most home shops. Which is likely true, as IIRC there is a specific set of temperature ramps and soaks needed to harden it, which is impossible without a heat treating oven.

Jim2
06-03-2013, 09:54 AM
@Norman: I'm not sure what problem you're trying to solve. I think my toolholder is overbuilt and not at all inclined to bend or flex. What are you trying to fix by broaching? If you don't like the hole behind the toolbit, there are a couple of different approaches to eliminate it.

1) You could slice a rod in half, cut the square cross-section into it, and then silver solder it into the toolholder. This has already been done.
2) Use a shaper to cut the square slot in the toolholder. I didn't do it that way, but the question was asked in this thread. I don't know that it would be that hard, but I am even more of a noob on the shaper than the other machine tools. . . .

Also, I'm not sure what you mean by:


To be fair I am not sure such a tool holder would suit my uses as near everything I try to make seems to have a square shoulder and these tool holders don't work well for that purpose.

Shoulders are one of the tool's strengths. It is easy to turn and face without having to re-position the toolholder.

Jim

Jim2
06-03-2013, 09:59 AM
You have the same ammount of material holding your cutter (its symmetric) - this is bad, since cutting forces push your cutter into its seat, so you should make that side thicker to dampen vibrations more. The best method for holding flats is by clamping; the australian tool sells HSS bits with dovetails on them, which is fantastic, but since you can't have that (its hard to make, or expensive to buy), i would recommend a wedge clamping underneat the tool, like how parting blades are held by wedge: http://shopimages.toolsnz.com/TNZ00255.jpg

It sounds like you're more of a fan of No 2 than No 3. . . .

I haven't had any trouble with the toolbit moving with any of the toolholders, but I'm usually not in a hurry. What I do is strictly homeshop stuff, not production.

Jim

Norman Bain
06-03-2013, 04:49 PM
Jim; I unreservedly withdraw my comment about the tool not being able to cut to shoulder. Clearly with the tool leaning forward at an angle the edge presented to the work is <90 degrees; so it can cut to shoulder and face without being adjusted.

Re: the what am I trying to achieve question. Only trying to assist ... spitball if you like. I think the design would be easier to create (fabricate) if the square section for the clamp was broached rather than milled. Milling would (for me anyways) require careful setup to get the two faces (and size) of the square hole section just right. Also the broach approach would allow for more material to be left on the nose; maybe even enough to get another clamping bolt in the area below and to the front of the cutting bit.

Norman

Jim2
06-03-2013, 05:17 PM
Yeah, I can see broaching being faster and more repeatable. Truth be told, the fit could be better on my toolholder, but the design is fairly forgiving in that regard. You just snug the bolts a bit more!

Jim

Shade
06-03-2013, 06:46 PM
Jim,

Nice craftsmanship on the holders, interesting to see the evolution.
But I have a question does this design have any benefits over
running a CCMT 2(1.5)x insert in an appropriate holder? Or is
it you did it because you could and it works well?

Ron

Sun God
06-03-2013, 08:28 PM
Obvious benefit - NO INSERT! 1 quality HSS (or even cast alloy, like Crobalt) tool bit, takes just seconds to resharp, and lasts nigh on forever, as you only take off a fraction of the length for every resharp. And you aren't reduced to throwing a $10+ insert in the bin if it chips.

Elninio
06-04-2013, 01:05 AM
It sounds like you're more of a fan of No 2 than No 3. . . .

I haven't had any trouble with the toolbit moving with any of the toolholders, but I'm usually not in a hurry. What I do is strictly homeshop stuff, not production.

Jim

It's not about the toolbit moving, its aobut cutting close to the shoulder without including your turret on a angle, or having your bolt break when you tighten it too hard

Elninio
06-04-2013, 01:10 AM
I want to grind a solid carbide 3/8" round (i.e broken endmills) into a square tangential cutting edge. Will this be a heavy load on my diamond cup wheel? I'm planning on doing it on the lathe, with the grinding wheel mounted in the lathe spindle.

JRouche
06-04-2013, 02:37 AM
Well Im not gonna try to give you advice on any part :) Naw.. Im gonna enjoy the fine pics and the work you did and toss an atta boy yer way. I like what you made and thank you Sir for sharing. JR

Jim2
06-04-2013, 09:57 AM
Jim,

Nice craftsmanship on the holders, interesting to see the evolution.
But I have a question does this design have any benefits over
running a CCMT 2(1.5)x insert in an appropriate holder? Or is
it you did it because you could and it works well?

Ron

I don't have much experience w/ carbide. I've only ever used brazed carbide on some large diameter facing projects. My lathe has a top speed of 350rpm and that rarely ever gets used. . . .



Obvious benefit - NO INSERT! 1 quality HSS (or even cast alloy, like Crobalt) tool bit, takes just seconds to resharp, and lasts nigh on forever, as you only take off a fraction of the length for every resharp. And you aren't reduced to throwing a $10+ insert in the bin if it chips.

Yeah, that's the ticket! The finish I get with the tangential toolholder beats everything else I've tried *on my lathe*!



It's not about the toolbit moving, its aobut cutting close to the shoulder without including your turret on a angle, or having your bolt break when you tighten it too hard

Well, this design is obviously not for everyone. I realize that folks that have lots of dollars invested in an expensive toolpost wouldn't have much use for this toolholder without some serious tweaks. . . .



Well Im not gonna try to give you advice on any part :) Naw.. Im gonna enjoy the fine pics and the work you did and toss an atta boy yer way. I like what you made and thank you Sir for sharing. JR

Thanks, JR!

Toolguy
06-04-2013, 10:06 AM
Elnino: I want to grind a solid carbide 3/8" round (i.e broken endmills) into a square tangential cutting edge. Will this be a heavy load on my diamond cup wheel? I'm planning on doing it on the lathe, with the grinding wheel mounted in the lathe spindle.

It will be a heavy load on your grinding wheel. Your lathe will not spin anywhere near fast enough to work well and you are wanting to move a lot of material. You may be able to worry it away over a long period of time, but it will be a long, hard row to hoe doing it that way. If you try to make it go faster with too much pressure you will break the wheel, the carbide or both.

Jim2
06-04-2013, 10:20 AM
Maybe you could use a square collet block to hold the 3/8" carbide and a grinder w/ a table? I was thinking that something along those lines might be another possibility for folks that don't want to broach out a square slot to hold the toolbit. . . .

Jim

Shade
06-04-2013, 10:41 AM
Obvious benefit - NO INSERT! 1 quality HSS (or even cast alloy, like Crobalt) tool bit, takes just seconds to resharp, and lasts nigh on forever, as you only take off a fraction of the length for every resharp. And you aren't reduced to throwing a $10+ insert in the bin if it chips.
Funny how different shops and experiences can be. I have been in and around the
MW business ever since I got out of High School. I was a welder in the Navy, got
my BS in Chemistry, and spend the next 20+ years running around in machine
shops and factories of all types. I spent 3 years selling tooling, mainly Sandvik and
Norton. The only HSS tooling I have for my lathe is one parting tool and, of course,
drills. The rest is a mixture of indexable and brazed carbide. I have a number of
friends that own commercial shops and I get a lot of donated carbide, inserts they
no longer use.

Back when I was running my welding (side) business I was picking over ePay and
CL for the inserts I like, now that I am just doing the machining for myself and such
I have a very good stock of inserts. I don't think I have ever paid more than two
or three bucks for general inserts, did pay cost from a friendly competitor once on
5 inserts Kennametal Top Notch for Acme threading. And some laydown threaders
from Iscar but both were for welding/repair jobs that I was able to bill the cost to.


I don't have much experience w/ carbide. I've only ever used brazed carbide on some large diameter facing projects. My lathe has a top speed of 350rpm and that rarely ever gets used. . . .
With a machine that tops out at 350 RPM, I can completely understand why. My
1989 Romi lathe runs between 50-2500 rpm, The most common speeds for me
is in the 400-600 RPM range.

Sun God
06-04-2013, 12:10 PM
Shade, that works great when you live in an industrialized area, but I for example, live in the industrial wasteland down under. I would have to drive an hour and a half to get to the nearest shop that sells carbide inserts, who want $10 per insert for chinese crap; half an hour to the nearest barstock supplier, whose range extends as far as A36, 4140HT, and some bearing bronze; and half an hour to the nearest fastener supplier that stocks anything more complex than woodscrews and galvanised mild steel bolts.

'Donated Carbide' goes straight to the metal recycler; most shops in the city (and unless I drive an hour or more to the other side of town there are few) won't let you in the door of the workshop if you aren't an employee, because of health and safety and public liability, so there's no such thing as picking through offcuts and scrap. What surplus tooling there is of use usually goes to one of several second hand tool dealers, with markups so steep you need crampons to get in the door.

Don't mean to have a whinge, but I wish I had it that easy...

Shade
06-04-2013, 12:57 PM
Shade, that works great when you live in an industrialized area, but I for example, live in the industrial wasteland down under. I would have to drive an hour and a half to get to the nearest shop that sells carbide inserts, who want $10 per insert for chinese crap; half an hour to the nearest barstock supplier, whose range extends as far as A36, 4140HT, and some bearing bronze; and half an hour to the nearest fastener supplier that stocks anything more complex than woodscrews and galvanised mild steel bolts.

'Donated Carbide' goes straight to the metal recycler; most shops in the city (and unless I drive an hour or more to the other side of town there are few) won't let you in the door of the workshop if you aren't an employee, because of health and safety and public liability, so there's no such thing as picking through offcuts and scrap. What surplus tooling there is of use usually goes to one of several second hand tool dealers, with markups so steep you need crampons to get in the door.

Don't mean to have a whinge, but I wish I had it that easy...

Not a problem, I do forget I have it pretty good, I live in the "Rust Belt"
I am a hour and a half from downtown Chicago, we have a lot of manu-
facturing still here in Illinois, even though our State government is doing
a great job of driving it out of the State (Illinois) I live in the country but
it is a 20 minute drive to Kankakee, IL where there is my steel supplier,
fastener, and bearing supply houses all close to each other. I also get up
to the big town several times a month for my employer and I always have
www.McMaster.com for those odd things, and most items show up next day
with ground shipping, McMaster is not the cheapest but they are reasonable,
very easy to work with and fast. Like the old shop sign says, you can have
it done, right, fast or cheap, pick any two.

I have back door access to half a dozen shops some were tooling customers
others were welding customers some were both all are friends now.

Elninio
06-08-2013, 12:23 AM
Anyone know if carbide square bits are sold, like how there are HSS squares?

RussZHC
06-08-2013, 07:48 AM
Travers and KBC both list square carbide blanks BUT the bulk are not actually square (rectangular section) and many are quite short (1.5" or so) but they do exist. I could only see C2 grade.
Rounds are way easier to find

Elninio
06-10-2013, 01:42 AM
I found a chinese (crap) 100mmx6mm square on ebay, but don't wanna go that route: http://www.ebay.ca/itm/Square-Carbide-Turning-Tool-Graver-/120821128190?pt=LH_DefaultDomain_0&var&hash=item1c21801bfe&_uhb=1
I think these are indented for wood turning.

Another guy is selling a 3/4" x 1/4" x 3" 'scraper carbide wear blade' (what is that for?). Rectangle shape is better, since more cutting edge is needed cutting axially than radially. You would be paying for more than you need otherwise (and more to sharpen) ... http://www.ebay.com/itm/solid-carbide-scraper-wear-blade-cutting-tool-rectangle-3-1-4-x-3-4-x-1-4-blank-/181133395971?pt=LH_DefaultDomain_0&hash=item2a2c644803

Turns out enco sells them in many shapes and sizes: http://www.use-enco.com/1/1/87935-solid-carbide-rectangle-rectangular-carbide-blanks.html ... I don't live in the USA though, maybe next month when I go to rhode island ...

Edit: found them at KBC: 3/8 x 1/8 x 3" , 16" if they have it in stock (usually don't)
Edit: Just got the little carbide sticks, they're not ground (this will limit surface finish). Probably made in china, of course. There's a little nick on one. Currently having a hard time machining a dovetail with an endmill. I have to be within 15 thou of the operational range of my QCTP.

Jim2
05-15-2015, 11:10 AM
It's been a couple of years now, and I've got a QCTP now. I've been busy this winter making up some tool-holders for it, so thought would add to this old thread. . . . Everybody likes pictures, right?

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Radiusing%20Tool/No%203/IMG_5055_zpstueuqjos.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Radiusing%20Tool/No%203/IMG_5055_zpstueuqjos.jpg.html)


http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Radiusing%20Tool/No%203/IMG_5058_zpsd4bzoh5m.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Radiusing%20Tool/No%203/IMG_5058_zpsd4bzoh5m.jpg.html)


http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Radiusing%20Tool/No%203/IMG_5060_zpsfw6rjfct.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Radiusing%20Tool/No%203/IMG_5060_zpsfw6rjfct.jpg.html)


http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Radiusing%20Tool/No%203/IMG_5057_zpskpciqphj.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Radiusing%20Tool/No%203/IMG_5057_zpskpciqphj.jpg.html)


So, I've got 3 made for the QCTP. My first effort was a 3/8" square bit. I had a few false starts there as you can see with the extra radii in the area where it attaches to the QCTP. I was attempting to drill the corners out and then meet with the shaper, however as per usual was working between older drawing, unverified measurements from internet, etc. and never bothered to verify against my toolpost before making chips! I guess there's plenty of metal there anyway, but definitely keeps it real. I made the square corner using the same/similar technique as I'd employed in the 3rd toolholder. There's a drilled hole in the back corner, and then the square sides were cleaned out with a small end-mill and a slitting saw in one setup.

The next one was the 3/16" diameter HSS model. It worked well, but seems to leave a little bit of a wavy surface at times, so thought another one with smaller diameter tool-bit might help. Last one is 1/8" diameter. There may be a slight improvement over the earlier 3/16" holder, but really not enough to bother. I would favor it over the larger bit anyway as seems to be just as rigid, just cheaper to buy bits, easier to sharpen, etc.

I'll add another posting to diagram some of the set-ups.

Jim

Jim2
05-15-2015, 11:19 AM
The first step is to drill out the back corner, if making a square-bit tool-holder or the hole for the tool-bit and the hole in the back of the slot.

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%204/TangentialMake-001_zps60ac7259.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%204/TangentialMake-001_zps60ac7259.jpg.html)


Then I make the square hole next. It may have been wiser to save this step until last as close viewing of the finished holder will reveal that I've got some extra machine marks on the front face parallel to the tool-bit. There were made when I removed a little to much metal to gain sufficient access to make the slot.

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%204/TangentialMake-002_zps0494baaf.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%204/TangentialMake-002_zps0494baaf.jpg.html)


I faced the "front", "side", drilled the holes to clamp, and make the slot.

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Tool%20Holder/No%204/TangentialMake-003_zps061a23a9.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Tool%20Holder/No%204/TangentialMake-003_zps061a23a9.jpg.html)

Jim

tlfamm
05-15-2015, 11:24 AM
Nice looking holders, Jim. Are they BXA or CXA?

Jim2
05-15-2015, 11:31 AM
After playing around with the radiusing tangentials on the lathe, I thought it might be neat to have a radiusing tangential flycutter.

http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Flycutter/No%202/IMG_5092_zpsqxuefniq.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Flycutter/No%202/IMG_5092_zpsqxuefniq.jpg.html)


http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Flycutter/No%202/IMG_5093_zpsab1rwhwm.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Flycutter/No%202/IMG_5093_zpsab1rwhwm.jpg.html)


http://img.photobucket.com/albums/v280/jasch/Metalworking/Tangential%20Flycutter/No%202/Flycutter2-002a_zpskpyxuvwo.jpg (http://smg.photobucket.com/user/jasch/media/Metalworking/Tangential%20Flycutter/No%202/Flycutter2-002a_zpskpyxuvwo.jpg.html)

I use this strictly for finishing work. Having purchased an r8 carbide face-mill from Shars, I can see that folks with carbide would likely say "why bother"? It does do a nice job, though probably still not even quite as good as the carbide. Being a larger radius, it does get used on occasion.

I've seen sticks of round carbide in 1/8" diameter on Ebay. . . . Does anyone have an opinion as to how they might perform compared to the HSS bits I'm using now? Would there be a particular grade of carbide that might be better than others?

thanks,

Jim

Jim2
05-15-2015, 11:34 AM
Nice looking holders, Jim. Are they BXA or CXA?

They're CXA. I'm using on old 15" Leblonde, circa 1924.

Jim

jhe.1973
05-15-2015, 02:14 PM
Hi Jim,

Thanks so much for starting and updating this thread. I didn't see the original series until today and it is definitely a keeper.

Nicely done work and great explaining!

:D

P.S. My only gripe is that now I have another project on my to do/make list. Just when I think I can find the end, project #693,478 comes along!

Jim2
05-15-2015, 03:28 PM
Glad to hear it. I was inspired by your work on that spin-dexer that you did a couple of years ago--turn about is fair play!

Jim