[RedneckPhysics]

Hi All,

Sorry if this is slightly Off Topic (this is all related back to my Tormach 770 setup adventure, I can assure you), but I was really hoping someone here has seen this in their own TTS tooling, and might be able to provide some insight. I'd find it hard to believe if nobody else has ever run into this.

I've found that 4 out of 4 brand new TTS ER-20 collet holders and nuts are galling up collets and nuts during torquing, causing some of the "fingers" of the collet to twist around further than others. Thus, the final assembled tool holder didn’t have a nice, even collet “finger” spacing as expected, and had to be trashed! The tested TIR was idiotic... 0.005"... probably a result of the galling (and its location).

Here are pics of two of the tools in question:


All parts were de-greased, clean of debris, with both nut and holder tapers given a very light coating of light oil (Starrett tool & instrument). It's likely the threads got some of that oil too, but I'm not sure how much.
The collets were inserted over the eccentric ring in the nut correctly, and well-seated. Tools were inserted into the collet, the nut/tool screwed onto the holder body and then torqued down to 57 lb. ft. Used a new torque wrench, which probably had an error to within 5%. That was just an average of a few values I found in looking around, and even the guys at Tormach said that was a fair choice.

After disassembling, I noticed quite a bit of galling and scraping on the upper (30 deg) taper surfaces, on both nuts and collets. Tool holder bores and collets both looked great.




Here are a few snaps under the inspection microscope (this was a nice Maritool collet too):


Tormach tech was basically silent on the issue once I mentioned how much tooling I went through, which is really uncharacteristic of them. Sad. In the end, it should run about $200 to replace the toasted stuff using "reputable" tools, considering S&H. Anyone have experience with these standard and bearing nuts from Maritool?

Some of the guys over at Practical Machinist suggested a very light smear of anti-seize instead (on the taper of the nut I suppose).

Even with the risk, it sure would be nice to be able to use some of the brand new nuts (have 3 left). Should they still work at lower torque values? I might sacrifice one new tool holder and nut combo, and go for a stepped-torque test. Maybe Tormach will sponsor me? Who knows.

For those who have used Tormach-brand TTS holders and collets without seeing this kind of wear, how have you torqued and treated them during assembly?

Thanks!

-Mike

[GenInt]

I'm going to hazard a guess, and suggest a way to do a quick check. First off, although it may help to hold things, the 30 degree angle where the nut meets the collet is primarily to force the collet down into the tool holder, and it's the 8 degree angle along the outside body of the collet and the inside of the tool holder that clamps the tool within the collet and the collet within the tool holder to keep anything from slipping. I think it's possible that there is is a problem with this 8 degree match between your collets and toolholders and the tool holder is only clamping the collet at the very bottom, (or very back edge), of where the collet meets the toolholder.

Try this: Using a 1/4" tool that you are sure has a good shaft, insert the collet into the nut, and insert the tool into the collet until it protrudes past the back end of the collet. Clamp it up in the tool holder where the gaps in the collet are uneven as shown in your picture. Now, look in from the back end of the tool holder, (looking at the back of the collet), and see if the gap in the collet match the gap irregularities on the front of the collet, or if the spacing of the gaps at the back of the collet are more uniform. If the gaps at the back of the collet appear more uniform, then there's a good chance that you are only gripping everything at the back edge of the collet, which is not what you want. If you find that the gaps at the back of the collet are more uniform, take everything apart, and clean the outside of the collet and inside of the tool holder with alcohol to remove any lubricant. With no tool in the collet, and without using the collet nut just press the collet into the tool holder as hard as you can. Having removed any lubricant, the collet should stay "locked" in the toolholder. You should see that all the gaps in the collet are closed at both ends of the collet where the gaps meet the hole where the tool would have been. If you find that the gaps are completely closed at the back end of the collet, but not at the front of the collet, then the 8 degree match is the problem.

If this is what you see, don't rule the possibility that you have 4 bad tool holders - especially if you got them all at once. These things are made in batches in China, and it is possible that all 4 of your tool holders were from the same bad batch.

GenInt

[MetalShavings]

I've never had any such problems with my TTS ER20 or 16 collet holding tools. I only hand tighten mine. That could be why I'm having no problems. I'm not sure how many foot-pounds or inch-pounds of torque I generate when I tighten the nuts down on my collet holders but, I'm pretty sure it isn't equal to the 57-foot-pounds you've mentioned that your's are torqued to.

I suppose it could be possible that without knowing it, during my lonely-masturbator teenage years I developed a super human torque grip but, I don't think so.

Have you tired wiping away any oils present on your end mills and collets interiors and just tightening/ torquing them down just enough to keep them from slipping? Putting anti-sieze on the threads is a good idea but beyond that, I think that over-tightening may be the cause of your problems.

MetalShavings

[109jb]

You mentioned that you used a torque wrench. Did you use a crow-foot or a socket on the collet nut. If a crow-foot, did you have it 90 degrees to the wrench so that the torque readings don't need adjustment?

[tmarks11]

How about getting ball-bearing ER-20 collet nuts? That would reduce the galling on the top of the collets.

https://www.maritool.com/Tool-Holder...duct_info.html

Also, how are you attaching the "crow-foot" adaptor to your torque wrench? If it is straight out from the torque wrench, instead of at a 90 degree angle, then you are effectively increasing the amount of torque you are applying due to the increased effective length of the torque wrench.

[MetalDawg]

That is crazy! I have been using TTS since March, and have had no issues at all. I am using the same fixture for tightening as well. As far as how much I tighten them down I would guess about 20- 30ft lbs. The same that I apply on the collet bar. I wonder if your batch of ER nuts were machined improperly.

[timbee]

No problems here either, not on the tormach using ER20 or on another machine using ER16 collets.

One thing i did that helped a lot, not on the ER collets, but on my R8 collet. i have a power drawbar and the TTS tools where sticking on release a little. i stoned the cut edges along the length to remove any burrs. That one thing made a world of difference in the performance of the power drawbar.

My point?
Are there any burrs on the collets? Never checked mine, but i'm going to. Never did anything but hand tighten my ER collets, in fact, thought i read somewhere that they are easily distorted by over tightening.

[RussMachine]

Wow, that's weird.
I have four ER20 TTS holders, and 2 complete sets of ER20 collets (Chinese made).
I've never had any issues with any of them.
I use a big, 1-1/16" box wrench on the collet nut, and a 7/8" box wrench on the tool body to tighten and loosen my collets.
I give them a good "OOMPH!" when I tighten them down, and I've had zero issues in 4 years.

[handlewanker]

Hi....the moment I read galling on a hardened steel surface it indicates the case on the surface of the tool is too thin and has been ground down too far when the tool was made.

I would suggest that the surface(s) of the item in question be tested for hardness ......it would also seem that the collets are made from case hardened mild steel, not tool steel, if they distort to that degree.

BTW.......I think the distortion that is forcing the gaps to be uneven is caused by the friction from the galling twisting the collet as opposed to applying the inward force to close it......that is, the nut is not smoothly sliding on the collet top angled face.

one thing that is also important and that is to have the right collet for the exact size you need.....Imperial for Imperial diams and Metric for Metric diams etc........ not relying on the ability of the collet to be squeezed down 1mm below it's size.
Ian.

[awerby]

I wonder if you're using the ER collet system correctly, Forgive me if you're experienced with these things, but you describe your process thus: "Tools were inserted into the collet, the nut/tool screwed onto the holder body and then torqued down to 57 lb. " You might have skipped a vital step.. The first thing you need to do is snap the collet into the nut, then you screw the nut onto the spindle nose, insert the tool, and torque it down. If you omitted that first step, then you're going to destroy your collets and the machining won't go too well either.

[tmarks11]

You might have skipped a vital step.. The first thing you need to do is snap the collet into the nut, then you screw the nut onto the spindle nose, insert the tool, and torque it down. .

+++1

[Paul-JB]

Oh boy. ya that would not be good putting the nut on a holder with a collet and tool already inserted.

[mactec54]

Hi All,

Sorry if this is slightly Off Topic (this is all related back to my Tormach 770 setup adventure, I can assure you), but I was really hoping someone here has seen this in their own TTS tooling, and might be able to provide some insight. I'd find it hard to believe if nobody else has ever run into this.
Thus, the final assembled tool holder didn’t have a nice, even collet “finger” spacing as expected, and had to be trashed! The tested TIR was idiotic... 0.005"... probably a result of the galling (and its location).
The collets were inserted over the eccentric ring in the nut correctly, and well-seated. Tools were inserted into the collet, the nut/tool screwed onto the holder body and then torqued down to 57 lb. ft. Used a new torque wrench, which probably had an error to within 5%. That was just an average of a few values I found in looking around, and even the guys at Tormach said that was a fair choice.

After disassembling, I noticed quite a bit of galling and scraping on the upper (30 deg) taper surfaces, on both nuts and collets. Tool holder bores and collets both looked great.

For those who have used Tormach-brand TTS holders and collets without seeing this kind of wear, how have you torqued and treated them during assembly?

Junk Collets and Nuts, buy quality and you won't have these problems

[mactec54]

I wonder if you're using the ER collet system correctly, Forgive me if you're experienced with these things, but you describe your process thus: "Tools were inserted into the collet, the nut/tool screwed onto the holder body and then torqued down to 57 lb. " You might have skipped a vital step.. The first thing you need to do is snap the collet into the nut, then you screw the nut onto the spindle nose, insert the tool, and torque it down. If you omitted that first step, then you're going to destroy your collets and the machining won't go too well either.

He stated how he assembled his collets into the nut for testing in the first post, the photo also show the collet seated correctly


RedneckPhysics posted this
All parts were de-greased, clean of debris, with both nut and holder tapers given a very light coating of light oil (Starrett tool & instrument). It's likely the threads got some of that oil too, but I'm not sure how much.
The collets were inserted over the eccentric ring in the nut correctly, and well-seated. Tools were inserted into the collet, the nut/tool screwed onto the holder body and then torqued down to 57 lb. ft. Used a new torque wrench, which probably had an error to within 5%. That was just an average of a few values I found in looking around, and even the guys at Tormach said that was a fair choice.

After disassembling, I noticed quite a bit of galling and scraping on the upper (30 deg) taper surfaces, on both nuts and collets. Tool holder bores and collets both looked great.

[handlewanker]

Hi, I doubt the tooling is junk if as the guy says they're Tormach stuff, although you can still have the TTS system with generic collets for economy, but it appears they're genuine Torrmach stuff.

BTW.....the assembly of the collet and nut appears to be in the correct sequence as stated in post #1.,,,,,,that leaves the quality of the collet and nut.

I'm amazed at the wear and tear in the tooling........normally the tools are set up in their holders and recorded in the tool register for diam and Z zero etc......otherwise you spend more time doing the zeroing.........constantly changing the tool for another apart from actual worn out tools, but due to not having enough tool holders, "could' cause wear and tear in the nut, but by that time you're bankrupt with tool wear

I don't see wear and tear or galling in the nut/body threads which also have the same if not more friction from tightening......that is.... axial thrust forces that act on the thread flanks and the collet top angled face.

Another theory.....if the main body taper of the collet is tight at the far or small end when tightened.....this will cause the top end to be loose in the taper and prone to twisting and distortion.......a dab of marking blue will tell all.

If these are genuine Tormach components............what has Tormach got to say.....shock horror if the tooling is the more expensive Gold class.
Ian.

[mactec54]

Hi, I doubt the tooling is junk if as the guy says they're Tormach stuff, although you can still have the TTS system with generic collets for economy, but it appears they're genuine Torrmach stuff.

BTW.....the assembly of the collet and nut appears to be in the correct sequence as stated in post #1.,,,,,,that leaves the quality of the collet and nut.

I'm amazed at the wear and tear in the tooling........normally the tools are set up in their holders and recorded in the tool register for diam and Z zero etc......otherwise you spend more time doing the zeroing.........constantly changing the tool for another apart from actual worn out tools, but due to not having enough tool holders, "could' cause wear and tear in the nut, but by that time you're bankrupt with tool wear

I don't see wear and tear or galling in the nut/body threads which also have the same if not more friction from tightening......that is.... axial thrust forces that act on the thread flanks and the collet top angled face.

Another theory.....if the main body taper of the collet is tight at the far or small end when tightened.....this will cause the top end to be loose in the taper and prone to twisting and distortion.......a dab of marking blue will tell all.

If these are genuine Tormach components............what has Tormach got to say.....shock horror if the tooling is the more expensive Gold class.
Ian.

Almost no hobby guy would be using a torque wrench to torque the ER-nut to the correct torque, that is probably why you have not seen this before, you need between 8 and 12 points of hardness difference between to ( 2 ) parts for this kind of problem not to happen, either the nut or the collet or both, have the wrong hardness

It is junk tooling from China and there is lots of it, everyone sells it, no matter who the supplier is, if the parts don't have the right heat treatment,this is the result

[tmarks11]

If these are genuine Tormach components............what has Tormach got to say.....

Tormach collets are low cost stuff made in China, and the price shows it. Not saying it is complete junk, but you do get what you pay for.

shock horror if the tooling is the more expensive Gold class..

You are getting your importers mixed up. Novakon is selling "gold class".... and they are $6 cheaper than the Tormach.... Still made in China. Still getting what you pay for.

Think about getting an ER nut that has a bearing on the inner surface. That would solve the galling problem.

https://www.maritool.com/Tool-Holder...duct_info.html

[R.DesJardin]

I've have had a Tormach sinc 2008, I have bought Tormach only ER holders ever year so I do a variety of years of mfg. I have never had an issue with galling. I used the a Tormach supplied open end wrench until the hex ones came out. They are long enough to get the tool tight and I have no idea what ft/lbs that is.

[RedneckPhysics]

I suppose it could be possible that without knowing it, during my lonely-masturbator teenage years I developed a super human torque grip but, I don't think so.

Have you tired wiping away any oils present on your end mills and collets interiors and just tightening/ torquing them down just enough to keep them from slipping? Putting anti-sieze on the threads is a good idea but beyond that, I think that over-tightening may be the cause of your problems.

MetalShavings

Bahahaha . And yeah, wish I had just used the supplied wrenches and gone that low-torque route first (but instead, I read and researched too much for my own good). This whole fiasco was due to my auto mechanic and engineering experience... whenever in doubt, use a published standard torque value first. I'm now re-thinking that mantra!!

Try this: Using a 1/4" tool that you are sure has a good shaft, insert the collet into the nut, and insert the tool into the collet until it protrudes past the back end of the collet. Clamp it up in the tool holder where the gaps in the collet are uneven as shown in your picture. Now, look in from the back end of the tool holder, (looking at the back of the collet), and see if the gap in the collet match the gap irregularities on the front of the collet, or if the spacing of the gaps at the back of the collet are more uniform. If the gaps at the back of the collet appear more uniform, then there's a good chance that you are only gripping everything at the back edge of the collet, which is not what you want. If you find that the gaps at the back of the collet are more uniform, take everything apart, and clean the outside of the collet and inside of the tool holder with alcohol to remove any lubricant. With no tool in the collet, and without using the collet nut just press the collet into the tool holder as hard as you can. Having removed any lubricant, the collet should stay "locked" in the toolholder. You should see that all the gaps in the collet are closed at both ends of the collet where the gaps meet the hole where the tool would have been. If you find that the gaps are completely closed at the back end of the collet, but not at the front of the collet, then the 8 degree match is the problem.

If this is what you see, don't rule the possibility that you have 4 bad tool holders - especially if you got them all at once. These things are made in batches in China, and it is possible that all 4 of your tool holders were from the same bad batch.

GenInt

Yes, awesome stuff, makes perfect sense. Trying this tonight!
As far as the batches, yes indeed, there is significant chance they are all from the same batch (I want to say I ordered 5 together "a-la-carte", and 2 came separately with various kits). All box labels look identical (my R8 TTS collets were quite different, for example).Makes me wish I kept those darned inspection stickers now! But even then, only about half of those stickers had a number written on them.

You mentioned that you used a torque wrench. Did you use a crow-foot or a socket on the collet nut. If a crow-foot, did you have it 90 degrees to the wrench so that the torque readings don't need adjustment?

Good catch! I tried to keep the post short, and forgot to mention that. Yep, properly compensated for the 30mm crowfoot. I said 5% to try to catch accumulated errors, but that value was probably too low. +/- 7.5% would be a more liberal guess.
And don't worry, I didn't fall victim to this mess :


Ohhh, man that makes me cringe! Torque trolls.

How about getting ball-bearing ER-20 collet nuts? That would reduce the galling on the top of the collets.

https://www.maritool.com/Tool-Holder...duct_info.html

Also, how are you attaching the "crow-foot" adaptor to your torque wrench? If it is straight out from the torque wrench, instead of at a 90 degree angle, then you are effectively increasing the amount of torque you are applying due to the increased effective length of the torque wrench.

Ahhhh, thanks, I forgot about the lever arm trick! If our R&D lab had some extra funding, I'd definitely buy a few bearing and high quality regular nuts. I've heard the ball-bearing nuts aren't so good at higher speeds. Do you think they'll balance "well enough" at 10,000 RPM? Just a guess, but practically speaking, might be a non-issue, since that extra holding torque shouldn't be needed for smaller diameter cutters running that fast. Sound right?

[RedneckPhysics]

Wow, that's weird.
I have four ER20 TTS holders, and 2 complete sets of ER20 collets (Chinese made).
I've never had any issues with any of them.
I use a big, 1-1/16" box wrench on the collet nut, and a 7/8" box wrench on the tool body to tighten and loosen my collets.
I give them a good "OOMPH!" when I tighten them down, and I've had zero issues in 4 years.

I've have had a Tormach sinc 2008, I have bought Tormach only ER holders ever year so I do a variety of years of mfg. I have never had an issue with galling. I used the a Tormach supplied open end wrench until the hex ones came out. They are long enough to get the tool tight and I have no idea what ft/lbs that is.

Almost no hobby guy would be using a torque wrench to torque the ER-nut to the correct torque, that is probably why you have not seen this before, you need between 8 and 12 points of hardness difference between to ( 2 ) parts for this kind of problem not to happen, either the nut or the collet or both, have the wrong hardness

It is junk tooling from China and there is lots of it, everyone sells it, no matter who the supplier is, if the parts don't have the right heat treatment,this is the result

I can't imagine the stock wrench could allow a seriously hard pull to put more than 40 lb. ft. into the nut/toolholder assembly, unless you've been doing some serious bulking up. That should've been my first clue, LOL. The second fail on my part was bypassing the "safety net" of the torque limit inherent in that one way bearing chuck/tightening fixture. In the picture with the tightening fixture, the wrench there was added to the holder's body, to keep it from twisting in the holder. But, I ventured on anyhow, thinking all would somehow be well in the end.
I now know just how much of an effect case hardening, precision grinding, and coatings (such as the Techniks PowderCoat) have on the longevity of these kinds of tools!