Removing collets

[master of none]

that's the way I do it cause it wont come out any other way I'm always worried about the bearings.

 

[Bob Korves]

We

Obviously I don't wail on it, but if that's not the generally accepted way to do it, I'm always open to improvement. How do you remove your MT3 collets?

GG

Well, I don't have MT3 collets, I have R8 collets. Same game, different players. The MT3 collets have a shallow angle and much longer taper than many other collet types have. There are several things going on here. One is how much power and how much pounding the collet's taper is going to have to hold back when cutting. Second is how much tightening of the collet it will take to prevent slippage. Third is how much push on the end of the drawbar it is going to take to separate the tapers afterwards. If it is an easy job, with light load on the spindle to tooling tapers, then you can tighten the drawbar less, and it will be easier to break the tapers apart later. You can oil, wax, chalk, or otherwise lubricate the tapers to make them easier to get apart, but that will also make them more likely to slip under load at an given tightness. You can also make a device that pushes the collet out of the taper by continuing turning the drawbar after the thread loosens up. You can make a support bar to go between table and spindle to support the spindle so the bearings do not have to support the impact of pounding on the drawbar. Different approaches will be more or less useful for the different issues you are dealing with. Understand what is happening, and try to use an approach that balances the benefits with the downsides for what you are trying to do on any given job.

 

[GarageGuy]

I don't know what to say. I guess I've been doing this wrong forever.

GG

 

[Tozguy]

To remove my MT3 collets from the lathe spindle, I use a long 1'' wood dowel through the spindle bore. I never use the drawbar to hammer out the collet.
Usually just a few taps using the dowel as a slide hammer gets the collet out because it is greased. If not then a dead blow hammer is used on the end of the dowel.
Several light taps is better than one hard one. Provision is made to catch the collet before it leaves the spindle taper and becomes a projectile.

 

[4GSR]

Back when we had our 9-J Gorton mills, a stuck arbor would happen more often than you expect. Sometimes they come loose with a light blow from a hammer. But had one that had a 2" face mill mounted on the arbor. That one, as the spindle heated up, would tighten up as the face mill was cutting. So if you didn't pop the arbor loose immediately after finishing that operation and let it cool, the arbor was pretty much shrunk fitted itself to the spindle. We literally had to beat on it with a 5 lb sledge hammer to get the arbor loose after trying to heat up the spindle by running for about an hour. Before beating on the spindle, I would place a metal sleeve around the arbor that the spindle would bear against so the beating did not go thru the bearings. Take about 4 to 5 blows to break the arbor loose!

Oh, BTW, the spindle taper was a No. 10 Brown & Sharpe. Yuck!

 

[Bob Korves]

I have a friend who spent lots of time working Gorton 9-J's and Master Mills. He told me the only way they could get the collets to release was to oil them before installation.

 

[4GSR]

I have a friend who spent lots of time working Gorton 9-J's and Master Mills. He told me the only way they could get the collets to release was to oil them before installation.

We never had any collets for our mills, just arbors to hold end mills. Made a collet holder to hold ER 32 collets later in life. The key to tightening the drawbar was to use only a 6" Crescent Wrench and gently tighten.