Dore Westbury Milling Machine

[Ian LParticipant @ianl48580]

Hi, When making a Dore Westbury MKII there was an option for the spindle to have a 3MT and no Myford thread on the spindle. Does anyone know what the diameter of through bore should be and what jaw bar diameter/thread was used for holding the chucks?

Thanks.

Ian

[Ian LParticipant @ianl48580]

[Brian WoodParticipant @brianwood45127]

Hello Ian,

I built my DW to the 3 MT specification. The through hole for drawbars is 29/64 inch diameter, I opened mine up a little over what I think the drawing would have shown as 7/16 inches.

At the time, standard drawbars were given a 3/8 Whit thread; with metrication today's versions are more likely to be M10

I hope that helps

Brian

[Ian LParticipant @ianl48580]

Hi Brian,

Thank you for the information, very helpful.

So I can assume the upper part of the spindle assembly came pre drilled at 7/16 diameter.

Ian

[Thor 🇳🇴Participant @thor]

Hi Ian,

I have a milling machine with a MT 3 spindle, and the drawbar for my metric tooling is M12, so 7/16" might be a bit too small.

Thor

[Brian WoodParticipant @brianwood45127]

Posted by Ian L on 28/11/2017 09:10:00:

Hi Brian,

Thank you for the information, very helpful.

So I can assume the upper part of the spindle assembly came pre drilled at 7/16 diameter.

Ian

Hello again Ian,

I built my mill over 25 years ago and I simply don't remember that diameter detail now I'm afraid. I can tell you that the upper part of the spindle was inserted into the lower part containing the MT taper and the joint was Loctited. I supported the parts with a chuck, tailstock centre and a fixed steady to centralize the joint while it set. It has never shifted since despite a lot of work, some with big drills using the gearbox to give the low speed and torque needed.

I did open out the bore some time later with a drill and extension pieces to 29/64 to give a little more internal clearance for a brass ended knock out bar and it should stand opening up still more for an M12 drawbar thread.

I have not had to do so though so if you are building I would also pin the joint and not just rely on the Loctite

Regards Brian

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