three belts better than two?

[Gregg Feldstone]

I'm thinking of getting a Sawstop and selling my Unisaw. I have noticed that the SS only has two belts, as opposed to the three on my unisaw.
What's the difference? Should a three belt saw run any smoother?

[Sean Kinn]

Well when I scrounged up my vintage Uni it only had a 2 belt sheave on the motor and I was a bit concerned about this. The concensus on the OWWM website was that with the modern materials used in belts these days that 2 was more than adequate. As for smoothness, I'm still only running two belts and I don't think it can get any smoother.

[John Ricci]

I wondered about the same thing before I bought my General 650R. It uses two belts instead of three but as Sean stated, there does not seem to be a problem with the twin belt setup. Oddly though, the General International saws seem to be a three belt configuration:confused:

J.R.

[Chip Lindley]

My *newer* 1998 model Powermatic 66 has only 2 belts, compared to 3 on older models. Unisaw has 3 also. The two belts are plenty to transmit 3hp to the blade. I would not be concerned at all ! I believe long ago, this was *insurance* in case a belt broke. The saw could be kept working until another belt was installed.

As an aside, my 5hp Powermatic 26 shaper has only one puny 3/8 belt! Amazing! And it does all that is required of it.

[John Thompson]

I have 3 on my SC 5 HP and my Uni had 3 belts.. the older PM's I have used had 3...

With that said.. I agree that 2 are fine as the theory of two has been tested and a number of manufactures are now going to two with the improvement of belts and the materials they are made of now as mentioned here.

Sarge..

[Steve Rozmiarek]

I think two is even over "engineered". I think the manufacturers are trying to get the most friction with the least tension. Tension could cause parasitic loss in torque, it seems to me, with a v belt. Better, more expensive belts would fix this though. Hard sell to put your saw out there with less belts, and make it cost more, when the other brand right beside it has a more "robust" three belt system for less!

A somewhat interesting piece of related info, I have a 12", 6.5ish hp euro slider saw with really excellent braking. It will stop the blade from full speed to stop in maybe a second. If anything where to make a belt slip, that would do it. My Felder uses 1 sepentine type belt. This type of belt is better at transfering power without parasitic loss. It's also a far more expensive system.

Agriculture relies on v belts. Every commodity that gets put into bins, either run up a conveyer or through an auger, is moved using this power transfer system. I have some old bins here in my yard. They have 7.5 hp three phase motors to drive the augers. The augers probably have 500 punds of grain in them when they are running full. We can trip overloads, but the belts, when they are in good shape, never slip. These are good two belt pulleys.

Guess I'm rambling, but, my point is that the one belt running most contracter saws is more then enough for any consumer grade tablesaw. Don't miss buying a better saw because the other one has more belts.

[Tom Veatch]

It's strictly based on power transmission requirements, not "smoothness" or anything else. A belt/pulley configuration can only transmit a maximum amount of power. That maximum amount is determined by a number of parameters, belt size, pulley diameter, speed/rpm, etc. If the power transmission needed in a particular configuration exceeds the capacity of a single belt, then multiple belts are used.

My 3HP Jet uses three belts. Quite possibly two would be sufficient. Three was used because the designers apparently felt that in that specific configuration, there wasn't enough margin with only two. The designers of those saws which use only two belts obviously felt that, in their configuration, two belts could transmit the power with ample margin against failure. Any number of reasons could be the basis of that decision including those mentioned above as well as what is felt to be "ample margin". But the use of two belts instead of three, or vice versa, is not prima facie evidence of quality or lack thereof.