More 'Chinese' collet action

I had long thought about getting some hex/square collet blocks and the recent thread on Chinese collets collets.

Reminded me that I had a Chinese collet chuck and collets lying unused since getting an er25 chuck. So I set about combining the two. Recently installing a dro on the mill meant that backlash is no longer a problem. So with the help of this online calculator

I set about turning the chuck into a Dodecagon (12 sided )

Nice one … I like that

MichaelG.

Are you going to cut off the taper and drill/bore through 16mm? Then you'd have a useful bit of kit to take long material.

John

Thank you Michael.

John, I'll probably leave the taper on until in need to use it with longer material.

Dave

Nice job but the dodecagon section is short so its inherently unstable lengthwise and will try to tilt forwards once the collet nut and workpiece are fitted. You need to figure out some way of restraining it to prevent such things happening.

Tailstock centre on a carrier of the right height perhaps.

Even the standard style of 5C collet blocks tend to be tippy despite being much longer and having the nut at the back so weight distribution is rather better. I regard a quick thump with a deadblow hammer to make sure they are seated flat in the vice an essential part of using those. I found out the hard way that simply pushing a 5C block hard into the vice wasn't quite good enough despite looking decently level. A hex with two sides tapered at degree or three looks seriously "wrong".

Clive

You also now have the bonus of being able to hold stock of the same diameter as the cutter you are using which can be an issue if you just have one size of collet