Collets on the lathe - what for?

[raynerd]

Hi all

As most of you know I am quite new to machining although did have a lathe few years ago. Anyway - I have been looking for bits and bats on the internet for additions to my mini lathe 12x7 and everywhere I look places are selling Collets. My understanding is they are mainly used on a milling machine in replace of the chuck to hold the tool piece, but the more I look the more I see collets being sold for use on the lathe.

Where are collets used in the lathe and more importantly why are they used - I presume they are using in the headstock to hold the piece rather than to hold the tool as in a mill. Anyone tell me why collets are used in the lathe and pictures most welcome!

Chris

[Darren]

Hi Chris, If you have a look at most of my posts in "projects" you will see one of my lathes that uses collets.

I use them all the time. Basically they hold the work very accurately, unlike a chuck. I can lathe a bar, take it out the collet, walk it around the block and put it back in the collet and it will still be true. Well almost, most of the time it is true, occasionally some dirt has crept in at some point.

Hope this helps...

[Stilldrillin]

Chris,

My 100mm chuck on my 7x12 repeats to .001"..... BUT it hasn`t had a hard or long life, yet! 

Collet chucks will carry on at .001", usually! 

David D