Bridgeport "M" Head

You cannot fit a MT3 spindle in that quill without an inordinate amount of work.
Define reasonably priced.
Jim

Hey Byron,
Hmmmm.... is that possibly a typo? I won't say you are hoping for something that can't happen, but my "M" head has only MT-2, and I've not seen any reference to MT-3 being available. I don't think the spindle is big enough for an MT-3 to fit in the diameter of the spindle available.
And I don't recall ever having personally seen a threaded MT-3 COLLET, which is required for the drawbar-pull, although I suspect that they do exist.
Good Luck. Take care.
Brian Lawson, Bothwell, Ontario.

I have a set of MT3 collets that are rear threaded, I think these are from sort of older import mill.I had used them in an old South Bend 9" to hold some work. No way to pass stock thru, but good for holding short parts. It would seem the cost to regrind your spindle would be better spent on a J head.

Hey again Byron,
In their 2001 (note that year!!) catalogue, KBC Tools listed a 3/8" BS-7 end mill holder as KBC # 7-156-010, and under another number a shell mill arbor. Not in the latest, or on the webpage now though. Seems like B&S tapers have run their course.
Just for fun, I did a cad drawing of the B&S-7 laid over an MT-2. WOWWWWEEEEE!!!! Are they CLOSE or what?!?! I never realized that before.
The MT-2 has a taper of 0.59941" per foot (for approximating only, say .6"per), and the B&S-7 is 0.50147 per foot (say .5 per), so you can see that the MT-2 tapers "more" or "faster" than the B&S-7. That's like only 100 thou over 12 inches! Not very much difference. Not sure I would see that difference unless they were laid side by side.
Problem is that the "small end" of the MT-2 is smaller than the small end of a B&S-7, by 28 thou. The B&S-7 is .600 and the MT-2 is .572. So, even though the grip lengths are 2-39/64 for the MT-2, and 2-7/8 for the B&S-7, the point where each exits the socket is .700 for the MT-2 versus about .720 for the B&S-7.
OK....supper interuptus...so I forget what I was doing, but I hope you get the idea.
I think you could redo the spindle you have to an MT-2 with very little trouble. I won't presume to tell you how, but it looks like a couple of ways to do so, either by cutting what you have, or sleeve, or sleeve and cut. It would require a lathe that has a 2-1/2" travel of the compound, and 3" would be better.
I do know that even the MT-2 collets are in a short list of sizes, but they aren't real hard to either make from scratch, or turn from soft centres that flood the market.
Take care.
Brian Lawson, Bothwell, Ontario.
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B&S #7 tooling comes up on ebay quite often. I just bought a 1/16" collet to complete my set. The seller had a bunch of collets for sale. They went for from .99 to 16.00 each. There's a 3/8" end mill holder for auction now. I'll probably make a boring head and an arbor for an Albrecht chuck or maybe just stick with straight shanks and use a collet. Tom