2MT taper tooling

[davebParticipant @daveb17630]

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

[davebParticipant @daveb17630]

Thread confusion.

[Frances IoMParticipant @francesiom58905]

my metric MT2 tooling + those for ER collets etc is M10 – most of the imperial tooling is 3/8th tho I also seem to have acquired a M10 socket for an imperial tool.

I’d have thought UNF would be too fine a thread for that use

[davebParticipant @daveb17630]

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

Dave

[John Stevenson 1Participant @johnstevenson1]

That’s the problem with standards.

There are so many standard standard’s

[BazyleParticipant @bazyle]

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.

[Anonymous]

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

Andrew

[Frances IoMParticipant @francesiom58905]

are BSW + UNC interchangeable – different thread shape – I acquired a home built MT2 taper which had a 3/8th UNC thread but my 3/8 BSW drawbar would not fit (at least it resisted enough for me not to force it)

[John Stevenson 1Participant @johnstevenson1]

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.

[davebParticipant @daveb17630]

Posted by Frances IoM on 10/09/2016 21:00:02:
are BSW + UNC interchangeable – different thread shape – I acquired a home built MT2 taper which had a 3/8th UNC thread but my 3/8 BSW drawbar would not fit (at least it resisted enough for me not to force it)

No problem, stick a 3/8 BSW tap down it. Dave

[MWParticipant @mw27036]

Posted by John Stevenson on 10/09/2016 21:02:08:

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

[thaiguzziParticipant @thaiguzzi]

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.

[Thor 🇳🇴Participant @thor]

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

[Martin ConnellyParticipant @martinconnelly55370]

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

[MWParticipant @mw27036]

Posted by Martin Connelly on 11/09/2016 09:19:54:

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

[Ian S CParticipant @iansc]

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

[duncan webster 1Participant @duncanwebster1]

Posted by Michael Walters on 11/09/2016 09:25:30:

Posted by Martin Connelly on 11/09/2016 09:19:54:

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

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

[AjohnwParticipant @ajohnw51620]

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

[Anonymous]

Posted by thaiguzzi on 11/09/2016 05:00:48:

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

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

[John Stevenson 1Participant @johnstevenson1]

Get a commercial 55 degrees rolled thread bolt and put it up on a shadow graph with a 60 degree one.

You will be pleasantly surprised to find out that neither are 55 or 60

[davebParticipant @daveb17630]

Thanks Thor, I will order one. Thanks also for the input of everyone who replied. I understand the difference between the thread forms but in this case, the fit is good enough for me.

Dave

[thaiguzziParticipant @thaiguzzi]

Posted by Andrew Johnston on 11/09/2016 10:55:28:

Posted by thaiguzzi on 11/09/2016 05:00:48:

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

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

Nah, probably the sort of people who have a Snap On top cab mounted on a Snap On roll cab, filled with every conceivable socket, and spanner, in every size, British, American, and Metric, by the brand names of Snap On, Mac Tools and Proto in that order. Oh, and a full set of Vise grips or "mole wrenches" too…

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