Myford M Lathe Speed

[James Jenkins 1Participant @jamesjenkins1]

Hi all,

I am going to be powering my Myford M using a 1HP 2,800 RPM motor. It's a DC motor, so I will be using a PWM to controller the speed, together obviously with the back gear. PWMs are great, but the low speed torque isn't quite there – but as I say the back gear should take care of that. I just want to use one gear ratio and then use the PWM for speed control.

Can you please tell me what you consider to the be optimum top speed for the lathe? From that I can workout which drive belt wheel to use and the size of the drive pulley.

Many thanks,

James

[James Jenkins 1Participant @jamesjenkins1]

[David George 1Participant @davidgeorge1]

Hi James as the spindle is running in plain bearings you should not over speed them. this is the original speed as on my lathe M type.

MYFORD / DRUMMOND M TYPE LATHE SPINDLE SPEEDS

600 RPM SPINDLE PULLY
MAIN DRIVE	BACK GEAR
850 RPM	100 RPM
600 RPM	70 RPM
400 RPM	50 RPM
330 RPM SPINDLE PULLY
450 RPM	50 RPM
300 RPM	40 RPM
200 RPM	20 RPM

David

[HopperParticipant @hopper]

I've got my M type geared to run about 950rpm in "top", 400 in "second" and 200 in low. Countershaft speed is about 400rpm to achieve this. Works fine.

I previously had it geared (pulleyed?) to run about 1200 rpm in top but found that the resulting 600 in second and 300 in low were a bit fast for most of the work I was doing. Bearings seemed to stand up OK to the 1200rpm.

[James Jenkins 1Participant @jamesjenkins1]

Hi all,

Very helpful and just what I was looking for – thank you. I'll aim for about 850 RPM with my gearing, as the actual voltage of the system is often a touch higher than the nominal 36v – due to the solar panel voltage – so the resulting speed is higher. I am hoping to avoid the need for counter shafting using the PWM – but only time will tell whether it can can deliver the power in lower speeds and whether I can get the pulley ratio reduction without it. The setup works on my pillar drill without any trouble, but the driven pulley is much larger.

I will let you know how I get on.

James

[HopperParticipant @hopper]

It'll be interesting to see how the 2800rpm motor performs torque-wise at 400 rpm or so without a countershaft. Keep us posted.

[James Jenkins 1Participant @jamesjenkins1]

Hi all,

I am finally getting around to doing this, having bought a Myford M countershaft. As I have mentioned before the motor I am using is a 2800rpm motor and the countershaft has a 9" A section pulley on the end (plus an 8" one). I am thinking of using a 2 1/4" driver pulley on the motor, which will give a countershaft speed of 700rpm. I know this is a touch higher than the usual 600rpm, but I will have PWM control to reduce this down to the required speed, as well the belt changes on the mandrel and the back gear.

Is there likely to be any issues with going from 2 1/4" to 9" in terms of belt grip, or should that be ok? Any minimum pulley distance to aim for?

Many thanks,

James

[Author]

Posts