Modify Delta 46-460 to spin slower?

[Prashun Patel]

I would like to enable my lathe to spin slower than 250 RPM.
This lathe is variable speed within three pulley ranges.

Has anyone done this?

Dumb idea?

[david privett]

I think space will be your enemy. But if you could add a shaft and bearing blocks pulleys and link type belts to make changes easier. You could get whatever speed slower you wanted. I thought about this when I had a tube lathe that spun 575 at it slowest speed and was about to do it. Then the g0766 came out and I bit on that bait it instead. Much happier I know now.

[Malcolm McLeod]

I would like to enable my lathe to spin slower than 250 RPM.
This lathe is variable speed within three pulley ranges.

Has anyone done this?

Dumb idea?

I have my Dad's Jet (similar) and have not done anything to it, but I too suspect the limiting factor will be space. Since the head-stock is essentially closed, any mods will have to fit inside. Or you have to go 'Rube Goldberg' on it - - maybe install a jack shaft where the motor is, and drop the motor under the frame?? (So using 2-stage reduction like many DPs.)

I see parts diagram for 3 versions of this lathe on Delta's website and 1 of them at least comes with a 5-groove sheave set. Could you install this set and get any additional reduction? ...But still fit inside the head-stock?

[Leo Van Der Loo]

I would like to enable my lathe to spin slower than 250 RPM.
This lathe is variable speed within three pulley ranges.

Has anyone done this?

Dumb idea?

Fit a turned ring over the handwheel where a belt can run over, then use a rotissery or similar motor to turn the lathe at a low

[Doug Hepler]

Prashun

Do you have a specific operation in mind that would necessitate the slower speed? For example, how much torque would you need?

Doug

[Paul Williams]

I like Leo's idea because you could arrange to have the torque level that you thought you needed. I plan to rebuild the control circuit on my 46-460 if or when the switch gives me more trouble than can be solved with dust control at the switch. I think increasing the size of the speed control potentiometer would slow the motor, but also reduce the available torque. This may be OK for sanding. To try this out you could temporarily add a variable resister in series with the speed control resister. Note I have not looked over the circuit diagram to verify that this would work.

[Prashun Patel]

I am trying to reduce the speed for sanding and scraping.

[Brice Rogers]

So, it seems that you are not looking for a lot of torque - - just a lower speed.

Leo's idea (attach pulley to hand wheel and drive with a second motor) would work. If the drag of the original motor was an issue, it could be turned on at a lower voltage so that it "went along for the ride" and wouldn't interfere with the second motor.

Another approach might be to use a DC motor like from a treadmill and a speed control. I suppose that there is even a chance that the DC motor could be put in the position of the original motor.

A third approach would be to drive the spindle from the handwheel side with a large variable speed drill. They are pretty cheap from places like Harbor Fright and under low torque loads might hold up fine.

I was thinking of trying a different belt/pulley arrangement on both a drill press and a Craftsman lathe. But the motor pulley was about as small as it could be and in my case, there wasn't enough room at the spindle for a much larger pulley. So a simple pulley switch wouldn't work for me. I suspect the same issue would limit Prashun.

[Doug Hepler]

Prashun,

This is an interesting question. I like Leo's idea. Also, could you plug the lathe motor into another speed controller? I don't know enough about motors to know whether that would work, but somebody would be able to tell you. As I understand the way speed controllers work, they reduce torque and speed simultaneously but there might be enough torque left to overcome the friction of sanding. I also believe that a motor will overheat rapidly if it stalls out because of voltage or load. I have that model lathe (good choice, Prashun) and I usually scrape at the same speed that I turn with a chisel, but to each his own. Finally, perhaps you could spin it with another motor, electric drill (as suggested above) from the right end of the work. That would give you more space for your second motor, and rails to mount it on. Put a ball bearing tailstock between the headstock and the work, so you would not need to worry about drag from the internal motor.

Fun question

Doug

[Art Moore]

If the speed controller is a PWM controller (and I assume it would be on this lathe), then torque is not reduced since the applied voltage stays the same. If it's not PWM, then you're correct that the motor will overheat at reduced voltage. If you could find schematics on the circuit, it might be possible to vary the low range limit.

[Richard Wolgemuth]

The 46-460 was the first lathe I ever bought and had the same issue - can I get the speed any lower. My solution was to buy a powermatic I still have the 46-460 and for some operations I prefer it to the powermatic. Also I like to have the higher speeds on the top end. Hope you find a more economical solution, although my solution was very gratifying

[Doug Rasmussen]

Slowing it down could be done fairly simply.


Replace the original motor with a stepper motor. Size-wise the stepper should be a good fit. Use a motor drive that allows speed control via a potentionmeter. The stepper motor is easily sourced, I can get you a model number on the Superior Electric drive if interested. You'll also need a DC power supply also easily sourced.


You might have issues with high speed torque.

[robert baccus]

I did one like Leo says 20 years ago--worked great. I removed the handwheel on a 16" Griz and replaced it with a walnut 10" handwheel with a V groove in it. Mounted a washing machine motor on a hinge ( for belt tension) and used only this motor and belt when roughing out--worked great for 2 years. Had to buy only 1 belt and small pulley.