[Roguish]

Are there any alternatives to purchasing an R8 to TTS collet from Tormach?
$39.95 seems really steep for a simple R8.....

[kstrauss]

The end of the collet needs to be flat rather than slightly convex as with most R8 collets. I seem to recall that someone posted an alternate source a few months ago. I suppose that you could grind the end on a normal collet to be flat.

[footpetaljones]

Tormach chops 100 thou or so off the end of the collet to recess it in the spindle now. Other than that, it's a standard 3/4" R8 collet, which can be bought from anyone.

[Roguish]

Do ya know if their collets are close enough to be able to use more than one, and still use the same tool offset?
Or are there collets one-offs?

oh, thanks for the replies.....

[kstrauss]

The collets do not affect tool offsets. The collet nose is flat which allows the rim of the TTS holder to contact the spindle nose which gives a consistent offset.

[cncoperator]

A word of warning. Having tested lots of collets there is wide variation in hole parallelism and TTS contact area when the collet is gripping. TTS is dependent on full length gripping the 3/4 shank and some collets only grip one end or the other of the shank.

[BGHansen]

I'd think you'd need a different offset for different collets. TTS nets off the ground surface after the collet is drawn hone with a 3/4" tool in place. Multiple collets would need to be identical from the taper to the nose.

Bruce

[kstrauss]

I don't believe that you are correct. A properly functioning TTS holder is gripped by the collet but its vertical position is solely determined by the spindle nose.

[BGHansen]

Yes, you are correct. The TTS collet draws its nose up into the spindle, so the datum surface is the surface of the spindle, not the collet end. My mistake, thanks for setting me straight!

Bruce