Est. 1998 — 27 years of woodworking knowledge
Table Saw RPM
Scott in Douglassville
Hi All -
It appears the motor on my ~30 year old Delta contractor's saw gave out. I'm confirming that, but conveniently, I have a new, spare 1.5 HP motor laying about. The rub: The motor on the saw is 3450 RPM, the spare is 1725 RPM. In practice what are the implications of running the blade at half speed? 1725 RPM still seems like it would be adequate for most everything I'd do.
Thoughts?
Thanks,
Scott
Re: Table Saw RPM
Lee Schierer in McKean, PA
Is there room to put a pulley on the motor that is twice the diameter of the pulley on the arbor? That would increase your speed to 3450.
Lee
Re: Table Saw RPM
Bill Tindall, E.Tn.
In practice what are the implications of running the blade at half speed? It will cut slower. I typically run a 7 1/2" blade on my Unisaw. Same effect as slowing the motor.
1725 RPM still seems like it would be adequate for most everything I'd do. Well then use it. Nothing like testing a hypothesis.
Try it...
John in NM
Worst case you find out that you need more RPM and have to get a new motor. The original motor on my saw was one of the old repulsion induction brush motors - it ran slower, 1800 rpm is what I remember but its been a while.
Re: Table Saw RPM
Jack Guzman from Maine
I'm betting it will work but you will grow to hate it because you're used to cutting at twice the speed. Get a bigger pulley like Lee said.
Re: Table Saw RPM
Steve Elliott
The cutting characteristics of a blade running at half speed would require the feed rate of the workpiece to be reduced by half as well to get the same chip load. If you can live with feeding the wood more slowly the saw should work fine.
Much of the time you might be able to use a faster feed rate anyway. I'd give it a try.
another wrinkle
Bill Tindall, E.Tn.
The blades are going to be designed to tension at 3500 rpm. The blade may not stiffen at half speed.
Feed rate
John in NM
I remember having to feed a bit slower with the old R-I motor on my ancient saw. Not much slower but a little bit compared to the saws I used at work (3 phase, 3 or 5 hp, I chalked it up to bigger motors).
Re: Table Saw RPM
AZ in Colorado Springs
It seems to me running at half speed, if that's in fact correct, the blade will not cut so cleanly. It might tend to grab at the wood, instead of having the inertia to cut cleanly through it. Be especially careful on your first few cuts until you see how it's behaving.
Re: Table Saw RPM
Jerry Gibbs
Curious what the blade speed was with old motor. Lot of table saws with 1725 pm. I would do the calculations. May be a simple pulley switch. Lots of pulley calculation help out there.