Collet size

[Lukebgb]

I have a question about collet size. How far off can you be with material size? Like if my material is 1.8mm can a 2mm collet be used or will that slightly damage it? 

[tomh207]

Happy to be corrected if wrong. My understanding (I have a lathe but too many other projects on the go) is that there is no wiggle room hence why we get 0.1 increments between collets, though most you will commonly see are jumps of 0.2mm. I think that it would be expensive for sizes a watchmaker would rarely use, e.g. the full current shaublin range of collets contains around 74.

@nickelsilver and @jdrichard are probably our most prolific current lathe users and might confirm.

 

Tom

[jdrichard]

I agree. The .1 increments ensur the correct size for stock metal used in making parts etc.  .2 increments may cause sizing issues.

[oldhippy]

It will also depend on how true your lathe is. 

[JohnR725]

15 hours ago, Lukebgb said:

I have a question about collet size. How far off can you be with material size? Like if my material is 1.8mm can a 2mm collet be used or will that slightly damage it? 

in the ideal perfect world you want your lathe collet to be the right size for the material so when you close it closes parallel to the materialist holding.if the object is either too big or too small when you close the collet will end up not holding parallel very likely it will still hold but the jaws will no longer be parallel possibly springing the collet. I'm not sure what the long-term effect of a sprung collet is because anytime you purchase one used more than likely somebody is had to tighten a little tighter to hold something that was either too small or too big. Other than all of this will probably just cause alignment issues especially if you would like to remove the object and put it back in again getting it back in without wobbling is going to be an issue.

[Neverenoughwatches]

16 hours ago, Lukebgb said:

I have a question about collet size. How far off can you be with material size? Like if my material is 1.8mm can a 2mm collet be used or will that slightly damage it? 

The better the fit as they say. You can see looking at the back taper where the most tension and hold is on a collet as its drawn into the spindle. Any part of the material inside the collet that is not held tight is going to have some wiggle room. That movement is going to transfer to the working end, how much is dependent on how much of it is actually held. If you are going to risk it bring something up with the tailstock  so you have both ends held.

[Dell]

The only way to get round your problem is to use an ER collet adapter and ER collets  because they have a better clamping range, if you use the wrong size collet ,if to big it will only clamp the stock at the front of the collet conversely if stock to big for collet it will only grip at back of collet both will cause runout and possibly damage the collet.

Dell