Re: 5C collet closer


Long story, so forgive me.

I had an early 405 9’ Workshop. it had a “Top Oiler” headstock, I Changed this out to a later side oiler. While I was doing thisI also used a 10K spindle.
(Yes the 9” Workshop and 10K have the same journal dimensions.)

The primary reason, at the time, was that the 10K spindle has a slightly larger bore. 55/64 vs 49/64, or 0.860 vs 0.766. This is enough to add a lot of versatility.

IN ADDITION the 10K spindle will accept a SB proprietary 6K collet. It does this without any adapter. These allow one to hold 5/8 stock through the headstock as opposed to the upper limit of 1/2 THROUGH THE HEADSTOCK with the 3C.

6K collets are expensive and rare, I took me about 8 years to collect a complete set. I can go from 1/16 to 5/8 in steps of 1/64.

I highlighted the 1/2 THROUGH THE COLLET because there are some 3C collets larger than 1/2” which, have an internal step bore, and allow you to insert material to a depth of about 1”.
I had them in steps of 1/64 to 9/16” at one time. I sold my 405 some years ago, along with the larger than 1/2 collets.

One thing which has not been mentioned. Is that the 3C/5C/6K collets are available in in botjh square and Hex. Not so with the ER’s.

I use 5C on my 10L and I do have some hex and square collets. I find them quite useful. I do have and ER-40 setup, but I mostly use that for odd size work, since my 5C’s are incremented in 1/32” steps.

I do miss having the 1/64 steps of the 6K’s but while I still have the collet set, I don't have a Lathe to take them.

One other note. The ER’s with their adapter stick out beyond the spindle 1.5 to 2”. I don't care for that.

Jim B

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