Best Motor for Drill Press: 1150 or 1750 RPM?

There is a Powermatic 1150 drill press available near me. I am considering making an offer. I want to replace the motor, because it's a 3-phase job. A 1750-RPM motor gives speeds varying from 450 to 4800 RPM. The 1150 RPM motor will give 260-3500. I don't want to fool with a speed control; this is a variable-speed press, so I'd rather just get a new motor.

Seems to me that the slower motor is better, because the upper end of the speed range is not particularly useful, while the lower end is good for big items.

Recommendations?

1140 rpm motors are usually specified for fans, with a constant load. And neither 3500 or 4800 rpm are very useful in drilling with any bit that a 1/2 to 5/8' chuck will hold. Too-fast producing overheating! Too-slow produces a poor cut in wood, and too much torque can be a safety issue!

Consult a drill speed chart for recommended speeds of bits you plan on using for metal and wood drilling. Both my drill presses have 1725 rpm motors and I have never wished for slower!

This stuff is making my head spin. Maybe the best thing is to spring for a VFD, buy a belt-change press, and get it over with. I wonder if it will lose power at lower speeds, though.

I think you're overthinking this. Just price a motor with an RPM, HP, and duty rating that matches what's on the machine now. Factor that in to what you're willing to offer.

What's more important is what condition it's in and what the seller will take. Don't be afraid to walk away from a thrashed machine at a high price. If it's in good mechanical shape and a reasonable price, it won't be available for long.

Pete

Will the speed range of the existing motor/VS rig satisfy your needs? If not, you have an ideal situation for a VFD!! In the horsepower you need, a VFD will likely cost you about the same or less than a new motor, and you gain even easier, broader speed changes. You may change the speed with both mechanical and electronic means if going from drilling wood to drilling metal. You will notice most VFD controlled lathes, etc. still retain some mechanical speed control because with a VFD you lose torque at low RPM- a motor metal/magnetics issue because a VFD controls speed by controlling the 60 hz line frequency up and down. The variable speed 1150 has Reeves drive for mechanical speed control. It is reliable and used on many similar drill presses, every Shopsmith ever made, etc. If you don't want to mess with two speed controls, just use the VFD to give you 3 phase, set it and forget it. You will always have the VFD capability to go above or below the RPM of the motor and Reeves drive if you need it. By the way, here is a link to manuals for the 1150.

If you go with a new, single phase motor, then you will likely want one with the same RPM for the same speed range. If you will be drilling any metal, then you want low RPMs. Google drill press speed charts. They are out there- a pick a speed range based on what kind of work you will be doing.

I have an 1150 and mine originally came with the option of three motors, 900,1100,1725 rpm's. I have the fastest and find the speeds adequate for my work. If I had to pick, and the three were equivalent $$$, I'd go for the slower which would be very handy of your spinning bigger hole saws or fly cutters.
My guess is one of the 3 motors will be less expensive than the others, that's the one I'd go with as at the far end of the speed ranges there really isn't all that much difference.
good luck,
JeffD

Hi Steve, a 1725 RPM motor will be less expensive than the lower speed motor (and smaller).

However if you want the lower speed range, purchase the lower speed motor.

Your drill press has a mechanical variable speed drive, so I'd go with a new motor as opposed to a VFD drive.

Regards, Rod.

Can anyone tell me if a non-variable (belt change) Powermatic 1150 with a VFD will have enough oomph to be useful for metalworking at low speed?

I'm not too happy with the prices I'm hearing. The dealer I found near me wants $850 each for his machines.

Get the VS, 3ph model if it's in decent shape. Keep the 3ph motor and get a VFD which will be cheaper than a new quality baldor for anything less than 3hp or so. The mechanical VS will allow you to keep the torque up while at the same time using the VFD to get the speed down low. You get the benifit of both speed reduction, but also braking with the VFD.

Mike

Quote:

---

Originally Posted by Steve H Graham

Can anyone tell me if a non-variable (belt change) Powermatic 1150 with a VFD will have enough oomph to be useful for metalworking at low speed?

I'm not too happy with the prices I'm hearing. The dealer I found near me wants $850 each for his machines.

---

It depends upon what you mean by metalworking.

If you mean hobby type stuff up to maybe 5/8" in steel yes.

If you mean bits in the MT3 range no. For heavier stuff you need a gearhead drill press.

Regards, Rod.

Thanks, Rod. Sounds like this thing will do anything I am likely to ask it to.

Prices will obviously vary greatly depending on location, age, and condition among other things, but I'd say from $500 - $700 is a fair range for a used 1150 in good ready to work condition. Dealers are always more expensive and you should definitely try to barter down. If they're not willing to budge I'd say wait them out until one comes up on CL or one of the other sites with used machinery. These are not rare machines by any means.
good luck,
JeffD