Im looking for a 2nd blade for my Dewalt 12" miter saw that I have been
using for 12 years. Thought Id get a blade to have while one is being
Seems like most blades now are the thin kerf. Any reason not to use those?
Current blade is .125 carbide. I wondering if the thin blades tend to
wander more. I dont care about saving material in the cut. Dewalt has a 2
blade pack that is good price but they are thin kerf. can you recommend a
good all purpose carbide tip blade?
thanks for any tip!
The outside of a saw blade runs faster than the inside, same rpm but
different mph. This means the blade wants to cup. The bigger the
diameter and the thinner the steel the more tendency there is to cup.
In addition each blade has its own harmonic properties. At
"critical speed" the blade will flutter. Then it will double
Anyway, not only is a big, thin blade easier to move but it also has a
greater tendency to move on its own.
This also means that it will be much less tolerant of fluctuations in
the equipment as well.
: The outside of a saw blade runs faster than the inside, same rpm but
: different mph. This means the blade wants to cup.
I don't see how this could be right.
If the blade is flat when it starts up, even if the differential
speed were to make it "want t cup", wouldn't the firces on each side
By the same token, if you were
to mount a rod perpendicular to a rotating shaft, the rod would want to
bend because the tip would be travelling faster than the part
nearer the sghaft. What direction would it want to bend in?
-- Andy Barss
I've been using one for years on the TS. The B&D hand saw, standard
blade, finally started making noises, so I bought a Makita which came
with a thin kerf blade. I still can't believe how easily it slices
through oak. There's simply less resistance, and I was taught early
on by my father to let the tool do the work, so I don't force
anything, just a steady guide. I'd have to look up the blade name
since it's a recent purchase. It might say something in their
In a perfect world saw blades wouldn't dull. It's when they do that
distortion happens, and a thicker blade holds out a litte longer maybe,
than that they cut about the same, and are a little bit easier on the
I have a Dewalt 12" saw and use a Forrest Chop Master and use that almost
exclusively for woodworking. I recently did a 2-room addition, so I bought
a Dewalt 2-pack of thin-kerf blades rather than use the Chop Master on 2x
material. I was amazed at how much the blades flex when cutting 2x
material. Of course, since accuracy is less important doing construction
than woodworking, I probably tended to bear down on the saw more, but still,
I could see the blade flexing on some fo the cuts.
For woodworking, and the like, I'd stick with full-kerf blades and take your
time with the cuts. Thin-kerf is probably okay for less finicky work.
This saw plate bending is not an obvious phenomenon.
Andrew Barss is correct in identifying the most important pressures on
the saw blade. However, as those forces are equalized, and the blade
gets thinner and is run faster and fed faster other, more minor
pressures, start to become more important.
Sawyers have been seeing plate bend for years due to cutting pressures.
"Self Bending" plate came as a surprise as saw blades got much
thinner. The forces on each side are roughly equal but the plate
wants to cup due to forces from the outside in. You are correct that
it could bend either way.
Think about a 30" mill saw that is 0.070" thick. What they do on
these blades is to use pressure rollers to roll compressed bands on one
side of the saw blade to prevent cupping. This is called tensioning
and compensates for the tension created during running. (Freeborn
covers this briefly on p. 25. If you don't have his book I can email
a copy free.)
This issue is not fully understood. It is an important part of the
Wood Machining Institute Seminars annually. In addition Forintek
(Canadian Forest Industries Technology) continues to do work on the
Anyway, the point is that thin kerf saw plate bends more easily due to
outside forces but also wants to bend on its own.
C = pi x diameter
Bore has about a 3 inch diameter
Rim has about a 36" diameter
At 10,000 rpm the bore edge is moving app. 6 mph
The cutting edge is moving 70 mph
P.s. The Freeborn Carbide Saw manual is free. Lowell wrote it and let
me put it on the web. there is no fee and you aren't on any mailing
list. Just email for a copy.
Unless I need to cut something at the full height of the blade I always
run a stabilizer plate between the blade and the nut washer (the fence
side of blade). It definitely keeps the blade more stable but I wonder
if it matters which side of the blade it is mounted on. Hmmm ...
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