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Shaper motor suggestions?

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PerryRT:
Folks -

I've been sitting over here in the corner listening for a while now, and finally came across something that might be of interest.

I recently bought a shaper. A 7" Delta/Rockwell shaper from 1952. It's in pretty decent shape and my goal is to get it running and reasonably accurate.

It is missing the motor setup, though. Originally, these shapers came with a 1/3 HP, 1725 RPM AC motor that ran a jackshaft (with about a 3:1 speed reduction as part of it) and then had a stepped pulley arrangement to provide four speeds for input to the bull gear. I'm missing basically everything in the "Shaper Motor Arrangement" picture (attached, I hope!)


So.... I guess I COULD try to find all that stuff, but frankly, I'm not interested in "restoration", I just want this thing to make chips so that I can figure out how a shaper works and what it's good for. As a result, my plan is to simply mount a VFD motor on the bench behind the machine, line it up with the input pulley and go for it.

Since I'm missing the 3:1 speed reduction, though, I was thinking of using a DC motor with a speed control here to improve low-RPM torque (also, looks like it's a little cheaper than an AC/VFD solution of a similar size.) My problem is that I'm not that familiar with the technology and wanted to check - do AC and DC motors "cross over"? (In other words, should I be looking for a DC motor of 1/3 HP ish? Bigger? Smaller?) Any tricks about buying DC motors for VFD usage I should know about? (I know that "inverter duty" AC motors are more expensive... is it the same in DC?)

What do you folks think?

Thanks in advance!

Lew_Merrick_PE:
Perry,

Forget HP for right now.  A 1/3HP motor running at 1725 RPM will have ((1725*1/3)/5252 =) 1.31 lb-in of torque.  At 3:1 speed reduction, that will turn into 3.94 lb-in of torque.  [Ignoring losses.]  That is the first thing that leaps out at me.

I have no idea how gutless the original shaper was (or if it was gutless).  1/3 HP 4-pole (1725 RPM) motors were common in clothes washers well into the late-1970s.  That would allow you to rebuild what was there relatively simply -- one approach.

If you are aiming at direct drive, then consider 1 HP your minimum.  So long as you can reach your desired cutter speed, more HP is unlikely to hurt.

PerryRT:

--- Quote ---If you are aiming at direct drive, then consider 1 HP your minimum.  So long as you can reach your desired cutter speed, more HP is unlikely to hurt.
--- End quote ---

Unfortunately, I have no idea how many guts this unit originally had, or even what more or less HP would really mean in terms of DOC/material removal - I've never used a shaper before. Frankly, I'm a little concerned about over powering it - this unit has a bakelite bull gear that I suspect would be a pain to replace if I were to strip something.

I am planning direct drive, though. 1 HP you say? That's a good start, I suppose. Again, I suspect that the key is to get the right torque at the right RPM.... does it sound to you like that should be around 3.5 to 4 lb-in at roughly 600 RPM is what I should be shooting for?

vtsteam:
If you're considering some of the common treadmill DC motors for sale on Ebay, be aware that they are often rated for that nameplate "horsepower" at 6000 RPM, or so, and often at an odd voltage, too. So you'll get considerably less usable power out of it, especially if you are using the speed controller to not only adjust speed but provide some of the reduction, rather than one or more pulley steps and/or a jack shaft. The actual power available at low RPM on the motor will be only a small fraction of the nameplate rated power.

btw, it's not so easy to overpower anything driven strictly by the usual single vee belt reduction after replacing a jackshaft with a speed controlled DC motor. It's possible to suffer more from belt slip problems. Depending on tension and puley sizes, of course, but a vee belt can serve as a clutch to prevent overpowering. Everything is dependent on specifics -- this is all generalization without them.

awemawson:
Welcome aboard.

A nice little shaper.

Does that work light REALLY go back and forth with the ram as it looks in the illustration? If so I can't imagine it lasting long.

Personally I'd stick to a mains synchronous motor in the quarter to three quarters horsepower range. I seem to remember that my 10" Alba 1A had a 1 hp motor so scale down from there.

My 18" shaper that I currently have has a humongous three phase motor with a hand operated star / delta starter and I shudder to think what the hp is!

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