Radial Arm Saw - rewire for the opposite spin direction?

[Allan Speers]

This is a serious question, and no I'm not insane.

I have an idea for using just the head assembly fo a radial arm saw, but for a different use.
Unfortunately, I'd need it to spin in the opposite direction, like a circular saw.

I know that many motors can be somehow "wired in reverse, to make this happen, but does anyone know if this would be true of ANY motor I might find in such a saw?


To be clear, this would be with a 12" 220v saw, so I assume that would mean it's an induction motor. (though I don't really know yet.)

Also, is this something I could do fairly easily, knowing very little about motors? I've seen some videos on the subject, but they are ot as clear as they might be.


thanks.

[Bob Vaughan]

Assuming it is a single phase motor, interchange leads 5 and 8. That changes the direction the capacitor shoots a startup charge to the starting windings.
If a three phase motor, interchange any two wires.

The more homework you do on electric motor theory, the easier it will be.
The actual execution may require more effort than you're willing to put out for the return on time and effort invested. Generally since a RAS motor is intended to run in one direction, one of the leads (5 or 8) will be buried inside so a rookie can't get at it easily and inadvertently get the motor going in the wrong direction.
Going by insulation color on the various wires can be risky because not all motors used the same colors for the various functions.

[Richard Coers]

Hope you don't plan on using the threaded section to secure a cutter. It will come off if you reverse the direction of the motor under load.

[Bob Vaughan]

Naturally, the threads will be turning in the wrong direction so the nut will unscrew rather than tighten but I figure you've already figured out how to solve that potential glitch.

[Allan Speers]

Wow, I didn't think about the threads.

Well.... nuts.

Maybe there's stll a solution, but it's getting complicated & expensive.

------------

Bob, thanks for that detailed reply. I haven't completely ruled this out yet, so.....

[Jeff Duncan]

Sure there is.... double nut it, just like you'd do on a reversing shaper.

Of course if your just using the head section, which I'm assuming means removing it from the saw arm, why can't you orient it so it doesn't need to be run in reverse?

JeffD

[Tom Welch]

Allen, Bob is correct, but I may add for 3 phase, swap any 2 "hot" wires to change the phase in order to change direction of the motor. All our motors we use offshore also has a ground wire.

[Bill Space]

Aside from double nutting, perhaps you could cross drill the shaft and use a Castle nut with a carter pin to lock the nut in place...

Just a thought. Should be cheap enough to accomplish.

[Bill Dufour]

My shaper has a keyway in the arbor shaft. It uses an internal one tooth washer under the nut so the nut does not see the torque from the cutter. If you will be using a blade, metal saws often have two drive pin holes drilled through near the arbor hole. roughly 1/4" holes so the arbor flange Has two pins that engage the holes.
My delta tablesaw has two 1/4" pin holes in the driven flange to unscrew the arbor for bearing replacement. It is a one inch arbor, the pins holes are on a 1+3/4 diameter. On my saw the extra holes are only used for repair work.
Bill D.

[Allan Speers]

Some great ideas here.

Thanks, guys!

This project will be a little bit down the road, but I'll post back here if I ever get it accomplished.

[Bill Dufour]

They do make small reversing gearboxes. either same rpm in/out or reduce/increase rpm. Someone used to make a drum sander that attached to a RAS and used the motor to drive the works. No idea if it even had a feed belt. I think it became the performax. which got bought out by Delta? You might see how they connected to the drive shaft.
Bil lD

[Peter Christensen]

The original Performax was a drum driven by the Radial Arm Saw motor, the drum support arm clamped to the column. It came with a pulley that was held to the saw arbor with the blade nut and washer. You tensioned the belt by angling the arm and rotating the motor until the belt was tensioned. There was no gearbox for it. Later that came out with a stand you could mount the arm to and use a dedicated motor. You could also get a belt feed to either use in the stand or on the table of the radial arm saw. I have the original Performax on the optional stand and belt feed. Used it yesterday. :)