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I'm looking to buy a 10" table saw and I see that blade RPM is noted on many of the listings. So far, I'm seeing numbers from 3400 RPM to 5000 RPM. I'd imagine that a higher RPM will make a higher pitch noise when cutting, but good hearing protection should help with that.

Beyond noise level, what impact does the blade RPM have on cutting?

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    Ideal RPM for carbide or tool steel blades is a function of diameter. What size is this saw? At 3400-5000 my guess is 10-inch, but we should be sure.
    – jdv
    Nov 13 '20 at 23:27
  • Yes, @jdv, it's 10". I've updated to question to note that.
    – FreeMan
    Nov 14 '20 at 1:24
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    It's not something I was aware of until just recently but higher RPM helps lower-tooth-count blades cut thinner material better. I'm not sure how much of an issue it is practically, but something to watch out for if cutting material thinner than the gullet size on the blade.
    – Graphus
    Nov 14 '20 at 9:41
  • @Graphus define "lower-tooth-count"... 24? 40? If one buys a "higher-tooth-count" blade, does that negate the drawbacks of a slower arbor speed?
    – FreeMan
    Nov 14 '20 at 14:53
  • Gullet larger than stock thickness, that's the thing to bear in mind. Regardless, you can still accommodate for a non-ideal situation by slowing feed rate right down.
    – Graphus
    Nov 15 '20 at 8:24
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Higher RPMs will also make better cuts, and extend the blade life, if the commercial cutting industry is to be believed. Many commercial lumberyards like to run their cutters between 10,000 and 18,000 surface feet per minute (SFPM). 18,000 would be a maximum ceiling, so they often aim for 15,000 SFPM.

Diameter * Pi * RPM / 12 = SFPM

At 10 inches and 5000 RPM we get something like 13,000 SFPM. At 3400 RPM we get 8900 SFPM, which might be too slow for most materials.

I'm not sure how this would affect blade life and cut quality in the home shop, but I'd assume a modest amount at or over 10,000 SPFM is what you want.

Now, these SFPMs might be about maximizing speeds and feeds, and it's not like lower RPMs are going to ruin anything as long as we reach a minimum. Almost certainly the SFPMs back in the water- or stream-driven days were lower. But there is definitely a sweet spot, which certainly drove the need for larger diameter blades.

But these are the typical SFPMs for carbide cutters. At the end of the day the max RPM at 10in is probably not the deciding factor for a new table saw. Things like build quality, motor quality, drive train reliability, and (most of all, at least for me) quality of the fences and guards. I'd take a lower RPM, better built, more easily serviced, and with a good selection of guides and jigs (or easy to adapt for home made guides and jigs) model over something that screams faster.

It's not like we should be in that much of a hurry.

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  • "might be too slow" Is this quantifiable in any way? Is there any demonstrable degradation? One of the saws I'm considering runs at 3450 RPM and is getting generally rave reviews, with no mentions of bogging down, or burning or other failure to cut satisfactorily.
    – FreeMan
    Nov 14 '20 at 15:47
  • This-all is very thought provoking, though I have to think that the meaningful other half of the commercial sawyer equation is feed speed. Any insight? (My guess is that they're throwing stock through pretty quickly, but I'm not exactly sure how that interacts with rim speed. And if we home-gamers are feeding much more slowly with a slow rim speed, does that cancel anything out?) Nov 14 '20 at 21:48
  • @AloysiusDefenestrate, yes I think you hit the nail on the head. Slow feed rate can allow for lots of things in power sawing, including resawing widish boards on the bandsaw with a blade very much not suited to that operation. Yes it's better to use specialised blades, but processing stock is not a race which is why so many woodworkers get away with GP blades for almost everything they do.
    – Graphus
    Nov 15 '20 at 8:27
  • Lower RPMs might result in higher torque, which can translate to performance improvements in terms of how the tool feels.
    – jdv
    Nov 15 '20 at 14:53
  • I would suggest that power is more of a concern than torque. The quoted RPM will be when the saw is unloaded, and power is torque*RPM anyway so a faster RPM at a given power actually equals less torque. Every saw motor will slow down when load is applied. If it's a single-phase motor then that's going to be the limitation before torque is.
    – WhatEvil
    Nov 17 '20 at 18:15

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