Lookin' for answers

[tdub4ever]

I'm hopin' some of you experienced scrollers can help. I have a Ryobi SC164VS with variable speed and an old Craftsman 24" 2 speed. I'm wanting to maybe somehow take the variable speed off the Ryobi and put it on the Craftsman. Like mentioned the Craftsman is 2 speed, too slow and too fast! On the high speed the blade breaks every time. I'm thinking if I hook everything up the  same way it might work, (but I know nothing about them) it just works in my head. So if anyone has any ideas I would be thankful!

[daveo]

In theory if you disconect the dual speed connection all the way back to the motor and then fit the variable speed unit it should work providing the wattage rating are equal or similar. But rather than butcher a machine why not leave the dual speed machine on high and incorporate a variable speed foot pedal, I did this on my machine by using a foot pedal from a sewing machine ( and she has not missed it yet)
Dave

[EIEIO]

Your 2-speed machine is most likely an AC induction motor. You should not just put a resistive divider (foot pedal speed control) on the front end of it. To vary the speed of an AC induction motor you should vary the frequency while maintaining the Volts/Hz ratio. Right now it is 120 volts at 60 Hz, so Volts/Hz = 2. The fully variable scroll saws use a DC motor that is much easier to speed control.

Take a look at drives like this ($25) if you have a brushed AC motor on the Sears unit:
http://growace.com/speed-bully-motor-speed-controller.html?gclid=CM_f_N3QkbkCFQJqMgodaycAnw

If you want to move the Ryobi drive, you need to move the motor as well as the electronics.   

[BilltheDiver]

Easiest answer: sell both on Craigslist and buy the machine you really like.  No offense intended, but often it is better to leave the engineering up to the manufacturer rather than perform risky modifications on what you have.

[mlwmerk]

An old wise man once told me: 

"If you want to make a silk purse our of a sow's ear, it is better to start with a silk sow."

[tdub4ever]

Thanks for all the feedback. I haven't had time to mess with it yet. Ray, I glanced at the option of exchanging motors and all, the motor on the Craftsman is like 2 or 3 times bigger than the Ryobi. Will look at it more this weekend. Thanks so much!

[dirtrider73068]

You can pick up the 16 inch craftsman variable speed for about 130 bucks, its what I use and love it.

[EIEIO]

I agree that changing the motor may not be possible - just pointing out that a Ryobi variable speed drive should not just be moved to an induction motor. Usually PM DC motors are smaller than induction, so what you said makes sense.

Sears tools have used brushed motors in the past - the back end of the brushes are visible on the outside of the motor body. The brushes mean there is a commutated field in the motor. Squirrel cage induction motors don't have a commutator.

If you can see the brushes (they usually ar about 1/2" diameter and have a screwdriver slot cut into them so the brushes can be replaced) then you might consider that variable speed drive that I mentioned earlier.