slipping collet!!!

[gibl5s]

Has anyone ever experienced a bit running out of the collet while cutting afile? I saw the problem and I put a new collet on the spindle and thought that had fixxed it but it did it again. I put a micrometer on the bit to see if it was worn but it wasnt. Just kinda worried about this happening again.
anyone ever had this problem?

[Ger21]

I've been using big italian machines for almost 20 years, and have never had a bit come loose. And we cutt at 1200ipm (20i/s) full depth through 1" thick materials.

If you have bit's coming loose, there are only a few things that it could be.

1) It's just not tight enough. I think this is the culprit in the majority of cases.

2) defective collet

3) collet not installed in the nut correctly

4) bottoming the bit out in the collet

[gibl5s]

Thanks so much for your reply Gerry. Tell me this, I have read that the collet should not be tighten real tight in order to not do damage to the collet. What do you say?

[scottp55]

Perry, Gerry is on the money! Most likely is # 3 & 4.
Hope you threw the bit away also.
If possible, position your wrenches so a VERY firm 1 hand tightening is possible. If I have to struggle with 2 hands to get it off--I KNOW it was too tight. You disassembling collet and nut at every tool change and blowing out or brushing material out of both them and the spindle?

[Ger21]

At my current job, we use a torque wrench to get the proper tightness.
At my previous job, we just cranked them very tightly. These were ER32 collets, and I've never seen once get damaged. I honestly think you'd have a hard time causing damage from over tightening. From my experience, people tend to under tighten far more often than over tightening.

[Brady Watson]

...we use a torque wrench to get the proper tightness.


Yup...but few will ante up for the setup. It ain't cheap. I'm pretty sure Techniks (http://www.techniksusa.com/) has them.

-B

[Burkhardt]

Good article from Tormach (www.tormach.com/uploads/163/TD31090_ToolHolding-pdf.html) about collet slip. More oriented towards draw bar collet types but interesting ideas about what to lubricate and what to keep dry.

Maybe the problem happens when the nut is insufficiently lubricated and most of the torque is needed to overcome the nut friction (or seizing) and too little is left to wedge the collet into the taper.

[Ger21]

Yup...but few will ante up for the setup. It ain't cheap. I'm pretty sure Techniks (http://www.techniksusa.com/) has them.

-B

Neither are a dozen HSK63 tool holders. :)

[Bob Eustace]

Here is the link to Brady's suggestion - brilliant idea and coupled with the thrust washer nut you'd end up with the perfect system.

http://www.techniksusa.com/metal/torque_wrench.htm

[Ger21]

That's the wrench we use.

[feinddj]

I just picked up a pair of ER25 Ball Bearing Collet nuts. They are supposed to have less vibration and a better hold. They are from Maritool. They seem to work just fine and if anything, I have had to back off on tightening as they lock down so smoothly that you don't realize that you've tightened a bit too much

[Burkhardt]

I just picked up a pair of ER25 Ball Bearing Collet nuts. .....
Me too, but for ER20 and had it shipped from that place in the UK that was mentioned here in another thread. I also positively impressed so far. Not sure about better vibration, but I noticed a little better runout.

[gibl5s]

Hey thanks so much guy's. Makes me feel that I'm not paddling this boad all by myself.After changing the collet AND the bit and after 9hrs.48min of cutting we have a great looking frame with a leaf texture in the center. When I started this I had 6 hairs in my head now Im down to 3 and they are loose ha.
Thanks again

[mikek]

Perry, I have had that happen. I use a PC router and was using a CMT extension and it fell out. Scared me a bit! I came to the conclusion that it just wasn't tight enough. I now use an offset wrench to tighten the PC collet. I keep both of these in a conversation only drawer for show and tell. You can see from the picture where it spiraled out at 12,000 RPM.

[kerrazy]

Is it a true Spindle, or is it a Router?

I have seen with routers, where heat from wrong feed and speed rates will cause glazing on the collet from dust particles. This will prevent your cutter from being secured properly.

[rhfurniture]

Brady, I don't think it has to cost an arm and a leg. I just cut a square hole in a standard er25 plate spanner and use a standard cheap automotive square drive torque wrench (I hold them together with rubber bands!). I tighten to about 2/3 of recommended which is still way more than what I used to do by hand and guesswork, so it doesn't have to be deathly accurate, and it works fine.

R.

[Brady Watson]

Roger that Ralph. I'd have no trouble fabbing one out of mild or SS, but most wouldn't have a clue how to broach a 3/8 or 1/2" drive into it. These kids today...:D

-B

[kerrazy]

Mike,
I also recall a significant scare using a quick change collet on a router spindle.
Only used it once and never again.
Still have it sitting in a tool drawer.