Variable Speed Midi Lathes

[Tapper]

Just a quick question: I will be putting a Delta Midi Lathe into service soon, not the current variable speed model, but rather the older model where you move the belts to get different speeds. Can a VFD be used to attain variable speeds, instead?

Thanks,

Doug

P.S. Just thought that maybe I should post this in the "Turning" section, however the question I asked is not about turning per se, but rather more suited to the general tool group. Mods, feel free to move if you like. Thx.

[MichaelMouse]

Just a quick question: I will be putting a Delta Midi Lathe into service soon, not the current variable speed model, but rather the older model where you move the belts to get different speeds. Can a VFD be used to attain variable speeds, instead?

Minimum RPM of 500?  If you have a bandsaw, good enough for anything turned over the bed.  Varying the RPM is highly overrated and largely unnecessary for prepared stock, as long as minimum RPM is low enough.  Vary the tool feed and presentation.

Slowing the rotation with a VFD can lead to motor overheating, too.

[Foggy]

Minimum RPM of 500?  If you have a bandsaw, good enough for anything turned over the bed.  Varying the RPM is highly overrated and largely unnecessary for prepared stock, as long as minimum RPM is low enough.  Vary the tool feed and presentation.

Slowing the rotation with a VFD can lead to motor overheating, too.

I'm thinking he wants to do away with messing with belts.

[MichaelMouse]

I'm thinking he wants to do away with messing with belts.

Can't remember last time the 3000 was off of 680, personally.  And that includes symmetrical roughing at capacity.

[iclark]

Just a quick question: I will be putting a Delta Midi Lathe into service soon, not the current variable speed model, but rather the older model where you move the belts to get different speeds. Can a VFD be used to attain variable speeds, instead?

Thanks,

Doug

P.S. Just thought that maybe I should post this in the "Turning" section, however the question I asked is not about turning per se, but rather more suited to the general tool group. Mods, feel free to move if you like. Thx.

I couldn't find the thread n turning so answering here.

A VFD can be used to change the speed of a 3-phase motor. Unless the lathe already has a 3-phase motor, you would have to both change the motor and add the VFD.

There are also kits for some lathes with smaller motors to replace the AC motor with a DC motor and speed control. I do not know if there is one for your lathe.

[TDKPE]

I couldn't find the thread n turning so answering here.

A VFD can be used to change the speed of a 3-phase motor. Unless the lathe already has a 3-phase motor, you would have to both change the motor and add the VFD.

There are also kits for some lathes with smaller motors to replace the AC motor with a DC motor and speed control. I do not know if there is one for your lathe.

And it might be cheaper to find a treadmill somewhere and use that motor and control, assuming some capability on the part of the OP to fab and modify motor mounts and electrical gear. 

Even then, it would still be wise to select a mechanical speed range via the belt drive, then vary the speed with the control.  On my old 12" Delta with 1 hp TENV motor and VFD, I use a low speed for big stuff, and high speed for small stuff.  I never do anything but twiddle the knob from there.  

[Cian]

Penn State does offer a VS motor retrofit for some midi lathes, but am unsure if it will work with your specific machine:

https://www.pennstateind.com/store/TCLVSKIT.html

[Tapper]

Penn State does offer a VS motor retrofit for some midi lathes, but am unsure if it will work with your specific machine:

https://www.pennstateind.com/store/TCLVSKIT.html

Cian, thanks for this link. Did not know this mod was available. I was talking to a friend recently who is an experienced turner (after I posted this thread) about this and he said that changing speeds on my Delta lathe is not difficult. I'll need to get some experience with it and see how it goes. Thanks to all who responded!

Doug

[Cian]

Cian, thanks for this link. Did not know this mod was available. I was talking to a friend recently who is an experienced turner (after I posted this thread) about this and he said that changing speeds on my Delta lathe is not difficult. I'll need to get some experience with it and see how it goes. Thanks to all who responded!

Doug

That kit has come down in price over the years.  It was right around $200 or so years ago, but maybe demand has gone down since most are opting for VS right from the factory.  I had a non-VS Jet midi initially, but opted to sell it  before putting any real miles on it and got the VS model.  I still wouldn't call myself a turner but will be trying it agin today coincidentally.

[Bucko]

Not sure from sitting here all cozy while it’s snowing out but I rarely change the speed, thinking back only when I’ve rough turned a blank to slow down is reason.