Author Topic: Shaper motor suggestions?  (Read 9696 times)

Offline PerryRT

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Shaper motor suggestions?
« on: June 25, 2015, 05:30:40 PM »
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!

Offline Lew_Merrick_PE

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Re: Shaper motor suggestions?
« Reply #1 on: June 25, 2015, 05:51:37 PM »
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.

Offline PerryRT

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Re: Shaper motor suggestions?
« Reply #2 on: June 25, 2015, 06:04:22 PM »
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.

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?


Offline vtsteam

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Re: Shaper motor suggestions?
« Reply #3 on: June 25, 2015, 07:24:48 PM »
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.
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Offline awemawson

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Re: Shaper motor suggestions?
« Reply #4 on: June 26, 2015, 02:31:24 AM »
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!
Andrew Mawson
East Sussex

Offline RussellT

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Re: Shaper motor suggestions?
« Reply #5 on: June 26, 2015, 04:28:10 AM »
Does it still have the original stepped pulley on the side of the shaper? That gives some scope for adjustment of speed and torque.

You'd need the smallest pulley you can get for the motor (normally limited by the belt).  You could get more reduction if you changed it to a polyvee belt drive as you could get a smaller pulley on the motor (polyvees go in smaller radii).

Is there room on the side of the shaper to fit a larger pulley there?

How about some phots of the actual machine?

Russell
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Offline chipenter

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Re: Shaper motor suggestions?
« Reply #6 on: June 26, 2015, 04:50:52 AM »
I run a South Bend lathe with a 24 volt dc motor geared down 9 to 1 with a speed controler , below 10 rpm there is not a lot of power I screw cut at 50 rpm without using back gear for small to medium threads .
Jeff

Offline Lew_Merrick_PE

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Re: Shaper motor suggestions?
« Reply #7 on: June 26, 2015, 10:31:18 AM »
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?

Stop and think about this.  The original equipment had a 1/3 HP motor running through a 3:1 reducer.  The base equation is: Torque (in lb-ft) = HP X RPM/5252.  [I multiplied the result by 12 because I mostly work in lb-in for torque.]  It is torque that drives the action.  So, 1/3 HP X 3 = 1 HP.

Now, were you to place (say) a 5 HP motor on your system, you would run up your electricity bill a "tad" (call it 20% as a SWAG) and still only use the power required to supply the needed torque.  Though, personally (and not being familiar with the internals of your shaper) I would limit a direct drive motor to less than 2 HP.  It is all a cost/benefit analysis.

Offline RussellT

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Re: Shaper motor suggestions?
« Reply #8 on: June 26, 2015, 03:10:14 PM »
There seem to be some other variables other than the basic 3:1 reduction to the countershaft.

The stepped pulleys probably provide 2:1 1:1 and 1:2 and you need to think about when you would have need those ratios.  I suspect (and I've never operated a shaper so it may be rubbish) that it will depend on the job you are doing.  I think there is a further effective reduction depending on the length of the stroke - so a short stroke job will need less torque and can run faster than a long stroke job.

I think it'll probably work with direct drive - but if you can I'd still try and build in as much mechanical advantage as I could.

Russell
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Offline PerryRT

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Re: Shaper motor suggestions?
« Reply #9 on: June 26, 2015, 10:00:15 PM »

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.

No, it's fixed on a bracket on the left side of the ram (behind the ram in the picture). Still works, too!

Offline PerryRT

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Re: Shaper motor suggestions?
« Reply #10 on: June 26, 2015, 10:09:10 PM »
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.

Yeah - I researched that idea for repowering my lathe (different project) and hadn't considered one here because of the RPM that you mentioned.

What I was thinking about here was a 90 or 130 VDC motor from eBay around 1/2 to 3/4 HP and a speed controller to match, but as I said, I still have much to learn.


Quote
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.

I agree there. I just want to be safe, though.

Offline PerryRT

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Re: Shaper motor suggestions?
« Reply #11 on: June 26, 2015, 10:20:59 PM »
Does it still have the original stepped pulley on the side of the shaper? That gives some scope for adjustment of speed and torque.

Yes, the stepped "input" pulley on the side of the machine is there. I suspect that this unit was driven like I plan to (with a direct drive) prior to this. Unfortunately, I bought it from a dealer and don't really have a history on it.

Quote
You'd need the smallest pulley you can get for the motor (normally limited by the belt).  You could get more reduction if you changed it to a polyvee belt drive as you could get a smaller pulley on the motor (polyvees go in smaller radii).

You know, I actually haven't checked what it uses yet. I was kinda assuming a standard 3L or maybe an A because of the age, but that's worth checking out.

Quote
Is there room on the side of the shaper to fit a larger pulley there?
Possibly.

Quote
How about some phots of the actual machine?

Will be glad to provide them, but will have to wait until Sunday, I'm afraid - out of town with the wife for the weekend. Shhhh....everybody be quiet, she's noticed I'm distracted!  :Doh:

Offline PerryRT

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Re: Shaper motor suggestions?
« Reply #12 on: June 26, 2015, 10:34:25 PM »
There seem to be some other variables other than the basic 3:1 reduction to the countershaft.

The stepped pulleys probably provide 2:1 1:1 and 1:2 and you need to think about when you would have need those ratios.  I suspect (and I've never operated a shaper so it may be rubbish) that it will depend on the job you are doing.  I think there is a further effective reduction depending on the length of the stroke - so a short stroke job will need less torque and can run faster than a long stroke job.

I think it'll probably work with direct drive - but if you can I'd still try and build in as much mechanical advantage as I could.

Russell

The stroke length is governed by a scotch yoke set-up downstream, but that's a good point....for the same RPM at the input pulley, a longer stroke would seem to require more torque , right?

As for the stepped input pulley, I was honestly considering it as solely a way to set max possible speed and then leave the rest of the speed variance to the motor controller. In other words my plan is to set up the vbelt once and never touch it thereafter.

The reference books I'm reading seem to mainly talk about speeds/feeds in terms of strokes per minute rather than RPM, but due to the scotch yoke, on this shaper those are the same (ok , proportional) , 1 rev = 1 stroke. The total possible stroke defines the shaper, incidentally - in this case, a little over 7 inches.

We'll see. I have to admit, that's one of the reasons I still like this hobby - there's always more to learn.

Offline PerryRT

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Re: Shaper motor suggestions?
« Reply #13 on: June 28, 2015, 10:08:14 PM »
I spent some time today after we got back - last weekend I built a stand. It's a lightweight wooden job, but should serve (and if it doesn't, I've got another workbench.) Anyway, I didn't have much time, but I wanted to get the shaper up on the stand and figure out mounting/screws etc.

General shot from the left (non-pulley side) (Attachment 1)

A closer shot from the right side looking at the input pulley and table feed mechanism (Attachment 2)

and finally a shot of the end-on view of the input pulley (Attachment 3)

The rough dimensions of the pulley OD are 4.5", 3.5", 2.5" and 1" with a slightly over 0.5" pulley width (so I'm figuring an "A" series belt will work.)

One other data point I found - according to the original manual, the shaper was able to provide 40-180 strokes per minute. Again, I figure that the relationship between RPM and strokes per minute is consistent. However, it's NOT 1:1 as I thought earlier. Turning the unit by hand, it's about 6:1 (one full cycle of the ram for 6 revolutions of the pulley.) So that means that they were expecting no more than 1100 RPM at the input pulley, more or less.

More later - gotta do some math....

Offline Lew_Merrick_PE

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Re: Shaper motor suggestions?
« Reply #14 on: July 08, 2015, 10:29:56 AM »
>>  Stop and think about this.  The original equipment had a 1/3 HP motor running through a 3:1 reducer.  The base equation is: Torque (in lb-ft) = HP X RPM/5252

Brain Fart Alert!  The base equation is:  HP = Torque X RPM/5252 which gives:  Torque (lb-ft) = HP X 5252/RPM.  [And "5252" is "short" for 550 X 60/2pi which is more accurately stated as 5252.1131 just in case anybody's interested.]

Offline velocette

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Re: Shaper motor suggestions?
« Reply #15 on: July 08, 2015, 06:20:36 PM »
Hi
Had look at this posting and it looks like you are on the right track with a 1/2 hp DC motor and variable speed controller
Retain the stepped pulley setup  to give better torque at low speeds.
Suggest that you use only the three pulleys I.E. 2.5 drive 4.5 driven, 3.5 drive 3.5 driven 4.5 drive 2.5 driven with 4 to 1  reduction from the motor to counter shaft.
Being a dedicated nut case for DC Drives This would be the only way.
A tread mill motor will do the job But will need a wider ratio primary drive ratio.
Remember Chinese Horses are smaller so they have to run much faster to produce the horsepower.
A  DC controller can be set up to reduce the torque available at the motor shaft a bit fiddly but well worth the effort to minimize damage in a jamb up.

Eric



Offline NevadaBlue

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Re: Shaper motor suggestions?
« Reply #16 on: July 13, 2015, 01:18:06 AM »
I have a 7" Ammco shaper, essentially the same machine as yours. It does have the original motor and drive system. I would recommend building a jackshaft and using an ordinary 1/3 HP motor.  The machine runs very nicely with that setup. Also recommend using a link belt. I have changed my mill over to that type of belt too. Very smooth...
You will love the little shaper. It can do all kinds of things, including hypnotize you.  I love to watch mine run.  :dremel:
...
Ken