2MT taper tooling

I use a Bridgeport M head which has a captive drawbar. It's a nuisance to have to unscrew the drawbar locking ring to use a drill chuck (mine all have tangs). I want to buy a drill arbor to fit the drawbar. Arc Eurotrade only have 10mm. HBM list threaded arbors but state the thread as being 3/8 UNF. All my collets and other tooling are either 3/8 BSW or 3/8 UNC, for all practical purposes, they are interchangeable. How many different threads do MT2 arbors have?

Dave

Thanks Francis IoM.Yes, they can be bad enough to get out with a coarse thread.

Dave

Worth giving them a call to confirm it is UNF and not UNC. Could easily have been typed by some web designer who doesn't know the significance.

It might be UNF, after the standard drawbar thread for R8 tooling is 7/16" UNF.

Andrew

Usually on commercial thread the tolerances on rolled threads are enough that each will go into the other.

Might cause a few heart attacks with the flat earth and welded to armchair brigade but that's the truth, like it or not.

Or even the welded earth and flat armchair brigadiers.

Michael W

In the real world who cares about 5 degrees of thread angle.

3/16" to 3/8" BSW and UNC could and should screw into one another. I often tap UNC and fit a BSW fastener and vice versa. 7/16" up it all changes TPI wise. Unfortunately.

Hi Dave,

If I understand your first post correctly, you want a MT 2 drill chuck arbor with the shank threaded 3/8" W. Warco lists a MT2 drill chuck which is threaded 3/8W, and with B16 chuck taper, may be that could be of use? I don't know if that's the drill chuck taper you need though.

Thor

The shanks on drill arbors are usually soft down the core. Get one with a tang, cut the tang off and drill and tap to suit your needs.

Martin

I wouldn't like to garantee that, I would go to the trouble to anneal twice rather than chew my tools up.

Michael W

The probable resonfor using 3/8" UNF might be that hand drills like Black and Decker use UNF on their drill chucks and other attachments.

Ian S C

been there done that, anyone want a 3/8 BSW tap with the corners chipped off. Definately anneal

Cromwell sell an R8 arbour with a JT taper on the end and it's also possible to buy R8 drill chucks. Cromwell are a touch pricey but I hear cheaper if some one has an account but other places probably do them.

Assuming all of your other stuff is R8.

I'd guess the R8 drill chucks can be a touch more manly then 2 morse.

John

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Edited By Ajohnw on 11/09/2016 10:55:52

Edited By Ajohnw on 11/09/2016 10:56:59

Probably the sort of people who don't use a mole wrench on everything because it saves having all those different sizes of spanner.

Andrew