Female thread for C5 collet

[Lew Hartswick]

What diameter hole should be bored to thread that "odd" 1.238" (or some such) x 20 thread for a "nut" to pul the collet into the fixture??
Mach Hdbk doesn't seem to mention that little tidbit. Sort-of extrapolating from the info for a 1/4 x 20 I get about 1.188 or so. but
think think may be "simplistic". :-)
...lew...

[Doozer]

Nominal diameter minus the pitch.
Works inch or metric.
1.188" seems correct.

-Doozer

[Toolguy]

Most times that thread is listed as 1.240" OD. You can get by with a 1-1/4 - 20 tap for the collet puller thread.

The ID thread for a collet stop is 1.048 x 24. I wish they would have used something more standard for both.

[Mark Rand]

What it a C5 collet used on?

[RichR]

What it a C5 collet used on?

I think he meant 5C. You can get square and hex collet blocks for them. I think some spindexers accept them.

[Toolguy]

The 5C collet is most commonly used for lathe work. There are a myriad of different styles - inch, metric, round, square, hex, internal expanding, up to 6 inch clutch, machinable emergency in steel, brass and nylon, all sorts of adapters from 5C to whatever.

There are many jigs and fixtures for them too. Some of them are: collet blocks - square and hex, spin indexers, plain indexers, cnc indexers, tool sharpening jigs, etc. These are mainly used on the mill and surface grinder.

Darex makes an endmill sharpener that uses 5C to hold the endmill shank. There are 2nd op. speed lathes with a 5C spindle, probably others.

[JRouche]

And.... The Hardinge horizontal mill My endmill sharpener uses 5c also. JR

[Lew Hartswick]

Thanks fellows. I tried it this morning in aluminum to see if the "guess" would work. So started with a 1.180 hole and took .010 steps on the infeed .
(Used straight in-feed since I couldn't get the compound around far enough to use the "29 -1/2 deg" bit. The bit was made to cut on the back side
of the hole. So started at full depth and threaded "out" on the back side) . It ended up taking a LOT more depth of cut than I anticipated but finally
got to fit. So now That I know it'll work all I need is a piece of the right steel to make a good one. Think I'll try 12L14 for its supposedly nice easy
machine-ability. I'm going to see if measuring the internal diameter of the thread (as they now exist) with a telescope gauge for a better start
bore diameter. Should take a lot fewer passes.
...lew... Sorry about the dyslexia on the C5 vs 5C :-)

[Zahnrad Kopf]

I'm going to see if measuring the internal diameter of the thread (as they now exist) with a telescope gauge for a better start bore diameter. Should take a lot fewer passes.

1.200"

Don't ask. Just trust me.

https://scontent-ort2-1.cdninstagram.com/t50.2886-16/21815286_1007201079422178_1323672761297534976_n.mp4

[Doozer]

"C" means cataract, as in Niagara Falls.

-Doozer

[Toolguy]

My go to mild steel is 1215. It machines clean and easy, better than most of the more common ones.