Myford VMB

[Graham WardParticipant @grahamward47646]

I’ve just acquired a Myford VMB milling machine that appears to have had very little use. I’ve got it all set up and running nicely. There are still a few little jobs that I need to do but rather than post a list I was wondering if anyone has a manual I could have which would hopefully answer most of my questions.

Moving forward I’d like to be able to run the motor backwards (better for stud removal etc) and have a degree of speed variability if possible. I believe it has the original Brook Compton 0.37kw A/C motor. Any advice would be appreciated.

[Graham WardParticipant @grahamward47646]

[John HaineParticipant @johnhaine32865]

I have a scanned copy somewhere I could send you. PM me your email address.

[Graham WardParticipant @grahamward47646]

PM sent, thanks.

[OldironParticipant @oldiron]

Posted by Graham Ward on 07/06/2023 15:12:0

Moving forward I’d like to be able to run the motor backwards (better for stud removal etc) and have a degree of speed variability if possible. I believe it has the original Brook Compton 0.37kw A/C motor. Any advice would be appreciated.

Add a 3 phase motor and VFD. You get the best of all worlds then.

regards

[noel shelleyParticipant @noelshelley55608]

Or simply put dewhurst reversing switch on ! simpler and a LOT cheaper.Though no speed control. Noel.

[John HaineParticipant @johnhaine32865]

If you look at the wiring diagrams in the manual I just sent you can see the standard motor is capacitor start. You could arrange a switch to swap the connections to the run or start winding to reverse the motor. You can't vary the single phase motor speed.

I have to confess that I rather butchered my mill to fit a used 3-phase 0.75hp Crompton motor. The VMB standard speed changing arrangement is horrible, so I took the stepped intermediate pulley off and fitted it to the new motor shaft (needed a bush to reduce the bore) as it is pretty well the same sizes as the spindle pulley – mounted "upside down" of course. Then use only a single link belt between motor and spindle. 3-phase transforms the machine, much smoother and quieter and much less need to shift the belt. Reverse comes for free with an inverter. The main use case for reverse for me is tapping – set the inverter to a few Hz, bring the tap down to the work, start the spindle, keeping slight pressure on the tap as it cuts and with my finger on the reverse button. When deep enough just reverse the spindle to back the tap out. Haven't broken a tap yet, even once when I forgot to reduce the speed!

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