Boley Leinen motor options

[Henry RancourtParticipant @henryrancourt22682]

I’m looking for some help in what would be the best setup for selling my Boley Leinen lathe. Right now it has an AC motor with a foot pedal, but I made a new setup with a brushed DC motor, and a power supply and speed controller in an aluminum enclosure. One photo shows the present setup. The other photos show the new equipment not yet setup with the lathe. The new motor is just leaning against the AC motor. What one would you guys prefer?

[bernard towersParticipant @bernardtowers37738]

Either as both looked brushed so speed control possible, I would go for the quietest.

[Peter Cook 6Participant @petercook6]

Personally I would prefer the DC motor with speed control. I find holding a foot pedal at a constant position tiring on the ankles. It’s also harder to go back to the same speed when you stop for inspection/measuring.

Both my watchmakers lathes have variable speed control (mine are AC), and both are wired with an on/off footswitch so that I set the speed with the knob and switch the lathe on and off at that speed with a footswitch.

[Robert Atkinson 2Participant @robertatkinson2]

The original motor is a “universal” brushed motor so would run perfectly well from a simple mains speed control of the phase angle type. A quality example is this:

https://cpc.farnell.com/united-automation/csr2-10e/power-controller-pot-10a/dp/SC11525

Needs a case, fuse and switch of course.
Even a basic incandecent lamp dimmer would work OK.

Robert.

[Henry RancourtParticipant @henryrancourt22682]

I should have mentioned that the AC motor max is about 1,500 RPMs and based on existing pulleys give a max of 1012 RPMs. The brushed DC motor max is 5,000 RPMs and based on the same pulleys gives a max of 3,375RPMs. So DC motor provides much more speed flexibility. And, in general, AC motor torque drops at low speeds and DC motor torque remains strong at all speeds.

[Henry RancourtParticipant @henryrancourt22682]

Just realized the flexibility that a 5000 RPM motor provides. For example, with a speed control knob and a belt running from one 1″ diameter pulley on the motor spindle to one 1″ diameter pulley on the lathe spindle, that would provide the capability to run from 0 RPMs to 5,000 RPMs. So, no need to move the belt to different pulleys, so no need move the headstock to align different pulleys, now that’s flexibility. The finishing touch would be a digital RPM display showing the lathe spindle speed.

[bernard towersParticipant @bernardtowers37738]

Does the headstock have the ability to run at those speeds?

[Henry RancourtParticipant @henryrancourt22682]

I’ve seen many photos of watchmakers lathe motors, and many old vintage to new motors have RPM 5000 on their label. Some even use much faster sewing machine motors. Now I don’t know if users run their lathes that fast, but it seems the lathes are considered capable to be run at that speed.

[bernard towersParticipant @bernardtowers37738]

Plain bearings and unregulated lubricant supply I doubt it.

[Henry RancourtParticipant @henryrancourt22682]

Does anyone ever run their lathe at 5000 RPMs? Has anyone had problems due to running at high RPMs?

[bernard towers]

On bernard towers Said:

Plain bearings and unregulated lubricant supply I doubt it.

Well it does exist, maybe not in lathe headstock bearings but one example I know of is in the motors used in hard disk drives.

Some drives use FDB (Fluid Dynamic Bearing) run at 15,000 RPM and have an operational life measured in years once assemble with their (oil) lubricant.

Since watch pivots and other parts are extremely small diameter I would expect that precision made lathe mandrel bearings would be designed to run at high RPM with the right oil.

Link is to a white paper comparing ball bearing and FDB use in HDDs

https://documents.westerndigital.com/content/dam/doc-library/en_us/assets/public/western-digital/collateral/white-paper/fd-white-paper-final.pdf

 

IanP

[Michael GilliganParticipant @michaelgilligan61133]

If the plain bearings in Henry’s lathe are the classic “opposed double cones” in glass-hard steel AND are properly adjusted and adequately lubricated … they should tolerate being run at 5,000 rpm

But it’s a big IF

MichaelG.

.

P.S. __ What I really don’t understand is why people put such powerful motors on these little lathes

[Henry Rancourt]

On Henry Rancourt Said:

Does anyone ever run their lathe at 5000 RPMs? Has anyone had problems due to running at high RPMs?

I occasionally run my Taig at 10000 rpm when drilling sub-mm holes in brass for bushings. I find I break far fewer drills when I run fast. But the Taig bearings are spec’d for 10000 rpm.

I wouldn’t want to run either of my plain bearing watchmakers lathes at that speed.

[Michael GilliganParticipant @michaelgilligan61133]

[Peter Cook 6]

On Peter Cook 6 Said:

On Henry Rancourt Said:

Does anyone ever run their lathe at 5000 RPMs? Has anyone had problems due to running at high RPMs?

I occasionally run my Taig at 10000 rpm when drilling sub-mm holes in brass for bushings. I find I break far fewer drills when I run fast. But the Taig bearings are spec’d for 10000 rpm.

I wouldn’t want to run either of my plain bearing watchmakers lathes at that speed.

On Michael Gilligan Said:

If the plain bearings in Henry’s lathe are the classic “opposed double cones” in glass-hard steel AND are properly adjusted and adequately lubricated … they should tolerate being run at 5,000 rpm

But it’s a big IF

MichaelG.

.

P.S. __ What I really don’t understand is why people put such powerful motors on these little lathes

My brushed DC motor is far from powerful. At 4350 RPMs it only outputs 96.5 Watts which equals about 0.129 HP or 1/7th horsepower.

[Michael GilliganParticipant @michaelgilligan61133]

Good show, Henry … that’s appropriate.

MichaelG.

[Author]

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