Smaller blade in 10" table saw?

[Tom Hammond]

Hey guys. I just bought, at a local auction, an old Delta tabletop table saw 36-540 10". I got it to do small hobby cutting of material no bigger than 3/8" thick, and to set up for use by my grandson. I've got a number of super-safe jigs made so that he can do cross-cuts and kerfs for drawer bottoms, drawer side rabbets and the like... without me having to be in panic mode every second. But, after cleaning up the tool and getting it running well, I noticed that it is much louder than my regular table saw, and there's a lot of air coming off the blade. It *seems* the RPM is higher than my other saw. The blade mounts on the motor spindle (no belt). So... the only thing I know to do to slow down the torque at the blade edge is to put a smaller blade in this thing. Of course, I've got a dado set that is 8"... so I'm wondering if I can just put an 8" thin kerf blade on the saw permanently? I've not done that before, so I'd appreciate any advice from anyone who's done it. Sorry about the run-on paragraph... for some reason my Enter key doesn't work in this forum since I upgraded to Windows 8.

[Leo Graywacz]

Most table saws spin at about 7000 rpm. So with the blade connected directly to the motor I doubt it is spinning to fast.

Putting a smaller blade in the saw is perfectly fine as long as the arbor hole is the same size.


Hmmmm. Looks like I could be wrong about this. At least on my saw. Looks like a 3 1/2" motor pulley and a 3 1/4" arbor pulley. So about 36-3700 RPM

[Dan Grebinski]

7 1/4" blades work just fine as well. Its done all the time, as long as its a 5/8" arbor.

[Mark Draper]

Some blades just make more noise than others. I would be concerned more with the tip speed. too slow may be grabby and make a raspy cut.

[phil harold]

direct drives can be noisy buggers

[glenn bradley]

Universal motors like on your Shop-Vac, lunchbox planer or router are real screamers. This may be contributing to the noise issue as well as the fact that many saws in this format run at up to 5000 RPM where larger format saws have induction motors and spin the blade around 3500 - 4200 rpm.

I see no danger in running a smaller diameter blade unless it reduces the cut quality to a point where it becomes a safety issue. Like a dull knife, a saw that does not cut smoothly and easily can be dangerous. If the smaller blade requires more "push" to get the material through the cut, I would just buy better headphones ( a good set of Peltor's is only about $20) and deal with the noise. I cringe every time I see someone force-feeding a tablesaw.

[Jacob Reverb]

So... the only thing I know to do to slow down the torque at the blade edge is to put a smaller blade in this thing.

How does one "slow down the blade torque"? http://d26ya5yqg8yyvs.cloudfront.net/eek7.gif

A smaller blade will actually be HARDER to stop, not easier, because it will be doing less work per revolution. Which is easier to bind in the cut: A large drill bit or a small drill bit? Think: "lever arm length."

In any event, a table saw is not something I would ever think of as "super-safe," so long as it had a blade attached.

[Prashun Patel]

Would a 10in tk improve things?

[Tom Hammond]

How does one "slow down the blade torque"? http://d26ya5yqg8yyvs.cloudfront.net/eek7.gif
Oh, I'm sorry. Please pardon my conceptual inexactitude. What I should have said was that I wish to slow the blade edge SPEED. Better? The serial label says the motor runs at 4750 rpm. The Diablo 8" blade I have says max 9000, and my 10" says max 7000.

[Jacob Reverb]

What I should have said was that I wish to slow the blade edge SPEED.

But ... why? To slow down the kickback from 141 mph with a 10" blade to 113 mph with an 8" blade? Sorry, I guess my problem (besides snarkiness) is that I don't know what you're trying to accomplish.

To answer your question, no, it shouldn't be a problem to run a blade with a max rpm of 9000 on a saw that turns at 4750.

[Jim Andrew]

I had an old cman ts that the motor was very weak on, and I would put a 7 1/4 blade on to rip 2" material.

[scott spencer]

The biggest concern I'd have putting a smaller blade on a saw is safety. Smaller diameter blades tend to have thinner kerfs than 10" blades....when the kerf of the blade gets to the point where it's narrower than the splitter, the work piece can bind on the knife causing it to jamb. Be sure that the blade is at least as wide as the splitter knife.

[John Downey]

I know a guy who routinely runs 8" blades. Between the reduced kickback problems and the reduced resistance due to the thin kerf, he swears by the practice. As long as the kerf doesn't hang on the splitter (if installed) you will have no problem using a smaller blade.

I would stay away from framing blades myself, get a smaller blade that is designed for a table saw. The hook angle on the teeth can be drastically different and I've found the large hook framing blades can be very unpredictable when used on equipment not intended to run those blades. Never tried one on a TS though.

[Michael Dunn]

Perhaps I'm misunderstanding your original question. But, if you put a smaller blade in the TS your actually increasing the RPM's. This is due to the inner diameter having less distance to travel due to the shorter circumference. This is the concept behind gear ratios.

If I'm wrong, someone feel free to correct me. (As if one needs to ask fellow forumites to correct them, LOL!!)

[Jacob Reverb]

RPMs are RPMs.

Circumferential speed = RPMs x circumference

If circumference is smaller, the circumferential speed will be lower, if RPMs remain constant (which they would in a table saw).

Even under load, a smaller blade will maintain its RPMs (while driven) longer than a larger blade, all other things being equal, because it would have a shorter lever arm than a larger blade, and thus under equal "braking" force (from cutting wood), would be harder to bog down.

On the other hand, a larger blade would cut faster due to its higher circumferential speed. A larger blade does more work with each revolution than a smaller blade because it has a larger circumference and more teeth.

Think about your car. It pushes with more force in a lower gear than a higher gear, and is easier to bog down in a higher gear. Or think about trying to climb a hill with your bike without downshifting...or trying to go fast without upshifting.

[Tom Hammond]

Like I said... the primary (probably only) use for this saw is to crosscut small hobby stock and do kerfs of 3/8" depth and less, so I'm not worried about it "bogging down." What I am concerned about is the ease of use and safety... and it just seems to me that 4750 rpm on a 10" blade mounted directly to the motor spindle is a bit much at the blade edge. When I started the thing up, I was taken back by what seemed to me to be way more blade speed than I see on my regular 10" table saw or my 12" miter saws. I felt like the thing was going to take off and fly out of the garage. So, I thought a smaller blade might help. Thanks for the advice.

[Jacob Reverb]

4750 rpm wouldn't concern me. My Powermatic 10" TS runs at 4500 and my Bosch 10" miter saw runs at 4800.