I was given an M head with a Rockwell mill I bought, the M head had no collets. I cut the tang off a MT2 drill to see how it fit (I didn't think it would) and the MT2 is to small it goes up in the spindle a bit. So it looks like this is either a BS 7 taper or perhaps a bridgeport taper. So whats the best way to determine the taper without a bunch of collets to test?
You can determine the taper, or you can buy reasonably-priced replacement collets for the M head, at least in the US, from the folks at MSC industrial supply.
LLoyd
Wayne, if the nose opening at the very bottom measures 0.730" diameter (as mine does) then it might be a BS7 (definetly not MT2). Be aware that there is a third size. B3 I have never seen one of these, however. RichD
Its likely to be a 7 taper. Few BP tapers were ever used
Gunner
"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."
- Proverbs 22:3
The B3 ID is about 0.77" (just checked mine). The taper is short, and similar to R8, only smaller. The draw bolt is same as R8. If you're lucky, it'll be one of the others.
Pete Keillor
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