Blade Height

[scmhogg]

I was always told that the TS blade should be 1/4" - 1/2" higher than the thickness of the board. Or to the depth of the gullet. This was to allow the blade to clear the sawdust.

That 1/2" [and carelessness] cost me a little bit of my little finger, years ago.

The most recent issue of Wood Magazine, quoting the Freud Rep, opines that no more than 1/2 a tooth should stick up above the board.

This sounds a lot safer to me. Does anyone see any problems?

Steve

[HarmsWay]

Yeah I remember it is "the bottom of the gullet even with the top of the board".

I think it would depend a lot on the thickness of the board. A low blade combined with a thick piece of stock means there is a lot of bade in contact and very little opportunity to clear the dust. The blade would get hotter.

Any way you look at it, it's a compromise between safety and cutting performance. You pick your spot between the two. I suspect if I'd lost part of my finger on the saw, I'd be at the safe end thereafter.

Bob

[cabinetman]

I've read the data about blade height. Personally, I do what I'm comfortable with.
If the blade is at the height of the bottom of the gullet, then the angle of cut is the longest across the wood, and the cutting forces are toward the operator, pushing the stock upward.

If the blade is raised higher than that, the cutting forces are more in the downward direction, and there is less of a cut angle.

I may change the height depending on the type of wood and its thickness being cut.

As for accidents, it's hardly ever the fault of the tool. I've had many close calls and it's a lack of concentration or distraction that I attribute to most of the dangers.



"I'M NEVER WRONG - BUT I'M NOT ALWAYS RIGHT"

[gary]

Guy that taught me said the height if the difference between a laceration and an amputation. Which do you want?

[Knottscott]

I could be mistaken, but I believe that Charles M from Freud recommends about 1/2 a tooth protruding.

[drumpriest]

The gullet should clear at the bottom of the blade spin, and revealing it would only help with heat dispersion. A freud rep that I spoke with also indicated 1/8" or so, about 1/2 a tooth. I always went at the height required for the shark to clear properly, which is just a touch higher than the 1/2 tooth mark.

The reason for it being lower is that the angle at which the tooth enters the wood affects how it cuts, as well as the teeth involved in the cutting per unit time.

On the new saw, we'll see.

[Pappy]

I usually run +/- 1/4" exposed unless I am ripping narrow strips, then I get it as low as possible to make the cut.

[eezlock]

cutting height of saw blade....

usually.. I raise the blade 1/4" above the top of the stock, bottom of the gullet clears the workpiece and that is always fine....ripping ...as low as
possible. eezlock

[radhak]

once my blade stalled while cutting maple. i quickly shut the TS off and tried again, it stalled again. i checked - the blade was just half-a-tooth clear. so i raised it to clear the gullet, and tried again : the cut went thru pretty smooth after that.

hence i got a feeling a higher blade adds power (or whatever). would be happy with a better explanation of what was happening.

[vaking]

I have read that the wood should reach higher than the gullet, so that is consistent with 1/2 tooth showing. I am questioning the explanation about gullet showing completely to clear the dust. If the dust does get cleared at the top it would mean that the dust is thrown into your face. Why would I want that? I prefer the dust to be cleared inside the table and into the shroud. Also - if you try to show the gullet on a ripping blade (say 24 teeth) - you will have to expose a whole lot more than 1/2". Definitely not safe.

[LarryG]

I do almost exactly as Pappy does ... I don't turn it into rocket science, rather just crank the blade until there's roughly 1/4" showing and go.

Since the teeth do their actual cutting on the "down" side of the blade's rotation, nearest the operator, most of the sawdust in the gullets should be ejected below the table, before the same tooth emerges from the throat plate on the "up" side of the rotation.

[LinuxRandal]

Forrest blades recommends it higher. I believe you really have to check with the blade manufacturers, as they seem to recommend different things, due to design considerations.

[John Hunter]

I use the 1/2 tooth above as recommended by Freud.

[HarmsWay]

once my blade stalled while cutting maple. i quickly shut the TS off and tried again, it stalled again. i checked - the blade was just half-a-tooth clear. so i raised it to clear the gullet, and tried again : the cut went thru pretty smooth after that.

hence i got a feeling a higher blade adds power (or whatever). would be happy with a better explanation of what was happening.

The distance the tooth must cut at a single pass decreases significantly as the blade is raised. Apologies in advance if my math is bad (plus I'm over simplifying this) but take the example of a 10" blade and a 3/4" thick piece of wood in the attached sketches. With the top of the teeth even with the top of the wood (most safe), the distance is about 2.75" whereas if it were possible to raise the blade another 4 or 5" the distance would be 0.75".

If you think about that cutting angle, as CabinetMan mentioned, a higher blade forces the wood onto the table surface and a lower blade forces it at you.

Bob

[LarryG]

If you think about that cutting angle, as CabinetMan mentioned, a higher blade forces the wood onto the table surface and a lower blade forces it at you.

True, BUT if the workpiece raises up off the table -- the first stage of kickback -- the lower the blade is set, the less exposed blade there is for the workpiece to catch on and initiate a kickback. Or so my shade-tree logic says.