Question about my lathe?

[Dudley]

As most of you know, I just bought a used Delta 46-541p. I works great and has really got me hooked into the hobby. I was wondering about the pulley system on the spindle. It has a number of "steps" and a belt that comes from the motor. Why are there so many steps on a Variable speed lathe?

Here's a schematic of the lathe:

Also should this pulley system move freely from side to side? Because it does on my machine.

 

[Steve Worcester]

Step Pulleys on variable speed lathes give you a range of RPMs within one sheeve.

For instance it may have
100-750rpms
400-1200 rpms
800-1600 rpms

I don't know exactly on your lathe, but with the smallest pulley on the motor side, you will get the lowest rpms. Usually, you would use it when you want lower rpms for safety and more torque at low speeds for hogging out more material per cut.

As far as should they slide, not usually. There is probably an allen screw in the pulleys that has come loose. Before tightening, make sure to align the pulley sets, then tighten down the screw.

 

[Captain Eddie]

Almost there.

More about your lathe. This is an old cast iron delta sled. One of the finest basics available. This unit was designed to be used with the matching base and motor assembly.
Follow along with this logic. The step pulleys increase in diameter from the left to the right. The step pulley on the motor steps up from the right. If you have the belt on the far left the lathe will go the fastest. Large pulley on motor, small pulley on shaft. The opposite is true when you put belt on the far right. This lathe was originally capable of speeds from 550 rpm to 3450 rpm with a 1/2 hp motor. I have an original brochure from a 1946 model when it was Milwaukee Delta.
There is a flat spot on the shaft for the allen to set in. Be sure to slowly set the screw as you move the pulley around to get a good set. A loose screw lends itself to a few things, loss of power, noise, vibration and chatter.
You have a good lathe, it's easy to replace bearings, clean the wayes and it's very adaptable. Enjoy it. contact me directly if you need more help.
Capt. Eddie Castelin
The Bayou Woodturners
eddiecastelin@cox.net

 

[MichaelMouse]

Probably well to mention that the motor speed is important. I'm sure that you have one of the ~1725 rpm types.

For the curious, should you be one, the formula's motor pulley diameter over shaft pulley diameter times motor speed. Since it is a ratio, as long as you're consistent in how you measure pulley diameters, you should get close results.

With the Reeves, your bottom ratio's changeable. Your 541 is a Reeves, is it not? Means you check the basic ratios and apply the speed numbers on the dial for the final drive pulley. From the way it looked, I doubt anyone's altered the motor pulley diameter. Part 302, 41-032 could change all the nameplate values if it is not original. My shaft speeds went up on my four-step when I went from a 1/2 1/2 HP to a 5/8 shaft 3/4 HP motor, because the smallest diameter on the only cone pulley I could get was 10% larger.

All academic, of course, unless you're filing an insurance claim for a part that said don't use over X rpm. Turn as low as you can initially, and you'll be better able to integrate the new information your eyes and hands are gathering as the wood curls away.

Remember what Newton said! Energy is mass times the square of velocity.

 

[Dudley]

Thanks for all the information. I tightened the set screw. I'm pretty sure the belt is lined up with the lower pully system.

Michael,
Thanks for the formula! That will be a great help to me in the future.

 

[dkulze]

Hey Dudley,

The reason why there are so many different speeds is that you basically want to be able to turn a piece at a speed that is as fast as is comfortable, is slow enough to give you sufficient torque, and does not match a resonance speed for the piece.

The low end, as said, is for off balance pieces and heavy cutting. As the piece becomes more balanced or the cuts become lighter, you want to be able to increase the speed in increments, not just from 300 to 3000.

You'll find that most of your turning takes place at the lower end and the mid high. The only stuff that ends up at the really high end is small stuff like pens and bottle stoppers.

Dietrich