Reamers for ER40?

I may be a little picky here, but my collet holders are pretty damn hard. And are tapered, thus typical reamers are not an option.

Not sure why you want to machine things, maybe a little more info. DJ

The CQ6128A lathe has an MT4 spindle bore and a 1.5x8 threaded nose. The inner diameter of the bore is 26mm. I'd like to use ER40 collets with this if possible, where I can pass stock into the bore. Yes, I have seen the MT4 ER40 chucks on ebuy.

5C are 1.25 (or bigger) at the base. 3C collets go to 3/4, but they use a drawbar. 5C collet chucks only add about an eighth inch over ER40, so there's no extra cache to them...

Ace Eurotrade makes an ER32 collet chuck, but no ER40.

Mechanical Magic wrote:

Do you intend to ream the spindle bore for the collets?

What exactly are you intending to clean up? The MT4 taper is nothing like that on an ER40 collet. The closing nut thread is nowhere near your spindle nose thread either.

Why can't you just machine the ER collet holder with your lathe from a suitable hunk of steel? No need for a reamer just use the compound slide and a sharp tool.

I think another UK supplier do ER40 backplates, maybe Warco or Rotagrip.

No, the bore is too big. Wondering about making a collet chuck to thread onto the 1.5x8 spindle nose. Little Machine Shop (IIRC) has an ER32 chuck, but it's for the small lathes.

I have asked if it could be done with an ER40. No holy joy.

Chester has some heavy metal, and I don't mean some 80's boy band...

But no lathe ER collet chucks that I could see.

Louis Ohland wrote:

Thread a block of steel to fit onto the spindle. The rest is easy.

I'm looking at some 1-1/2 x 8 and 2-1/4 x 8 adapters I made to fit a Jacobs spindle chuck to my lathe. The larger one was turned from a thick-walled 'Cast Iron' pipe coupler which turned, bored and threaded very cleanly.

The smaller one was a cut-off from a hydraulic cylinder rod. After I turned off the chrome with carbide it machined nicely. I wouldn't try to make a precision part like this out of ordinary hot or cold rolled steel without first annealing it in the woodstove.

Jim Wilkins

Not to split hairs, but ER series collets (and others of similar design) are meant for tool holding, not really for work holding. Anyway, it should be an easy machining job to bore the one taper you'd need, the more complex features are in the nut, which I would just buy outright.

Get a er40 holder for an example of the taper and threads and go to it.

Regards Paul

No. Set the compound on the lathe at the correct angle and use that.

Buy an appropriate nut, if starting from scratch. They are cheaper than the time it will take you to work out how to make the eccentric on the nut.

If you are dealing with hardened material, a reamer would be a poor choice in any case, and would likely be ruined.

Cheers Trevor Jones

Put a collet on a mandrel and use a dial indicator to set the compound parallel to it.You can check the fit of the taper with bluing, or see if that mandrel wobbles or runs true when you tighten the collet nut.