Collet Trouble(Milling machine)

[NicelyMKV]

Yes, I did something real stupid. Just want to warn everybody and save a lot of time and money. Getting ready to do some collet maintenance, and for a split second, turned the collet the wrong way...... Still trying to find a way to remove the broken piece inside without removing the entire spindle and sending it in.........

 

[CoolHandLuke]

oh, i winced.

 

[NicelyMKV]

I'm in pain.....

 

[JohnWilson]

Ouch!

 

[ceram1]

Easy out should handle that. Good luck, let us know the solution.

 

[ParkwayDental]

Get a tap and die kit and make threads on the inside of of and maybe you can screw a bolt in it and try and back it out that way?

 

[NicelyMKV]

BadaBOOM!!

 

[NicelyMKV]

Well...... Ups just ran..... They sent the wrong damned collet......

 

[ceram1]

Ha! Glad to see progress though.

 

[rkm rdt]

Time for a reset

 

[Gabriel]

Just out of curiosity, do you usually tighten the collet using a wrench? I always just screw it on by hand and when I feel it's at the end I stop. Never had a problem with collets so far.

 

[CoolHandLuke]

with some machines the collet can be tightened by hand, others require the use of set screws and wrenches. not every machine is the same. when you replace a spindle, irrespective of what machine you have, that process can change depending on how the spindle was designed.

typically you don't want to thread the collet in all the way IF your machine uses a set screw inside. because when you tighten or loosen the set screw the height of your bur will change.

but if your machine doesnt use this screw then it may use a double wrench technique, with one wrench turning the collet, and the other stabilizing the spindle.

either way the collet needs to stop turning for you to screw it in to a tight position

 

[Gabriel]

I have a Yenadent machine, and I believe NicelyMKV has a Yena also. My spindle is a Jager. And from the way the broken collet looks, I would say that's a Jager collet also. These machines use the collets that screw inside, the inside of the collet is threaded. I agree, the length of the tool will change when you tighten or loosen the collet, that's why after screwing in or out the collet you should always get the machine to check the tool length.

The spindle automatically blocks itself into a fixed position when you instruct it to release the tool it is holding. After the collet holds no tool and is in the open position, the spindle is blocked and you can easily screw on or off the collet. No wrench needed.

 

[NicelyMKV]

Yes, I have a Yenadent as well.

I hand tighten the collet in my vhf mill with a calibration pin in place. I then open and close the collet three times to make sure the pin drops out without snagging etc.. I was going to do the same with the yena, but was instructed to give a light turn with a wrench.

I do spindle maintenance weekly on my vhf and was going to start doing the same with my yena. I was not paying attention and tightened the collet for just a fraction of a second. I heard a creaking sound. I went to loosen it and the collet fell in three pieces through the wrench....... They are extremely hard but almost crystalline like. Anyways, I learned my lesson the hard way. I will only hand tighten the collet for now on until I run into a problem.

Thanks for feeling my pain guys...