by Professor Gene Wengert
Q.
I was recently injured on a tablesaw at my workplace when a piece of material kicked back on the tablesaw. This saw kicks material across the shop floor several times a month. I and most of the people are aware of the problem so we stay away from the kickback zone. This time the material did a 180 degree spin. Luckily, I caught it with my right hand, preventing it from hitting my face or jugular vein. My hand did come up bruised and bleeding.
We are working with thinner materials such as plywood and plastic laminates--rarely more than 3/4" thick. The saw blade stays set at aprox. 4" above the surface of the table. Would lowering the blade height lessen the chances of kickback?
Since much of the material we work with is plastic laminates, lexan and Plexiglas, would there be a better pawling mechanism than the standard hook type? Possibly a wider knurled surface that wouldn't slip as easily?
We are using a very large radius course carbide blade. Would a finer blade with a smaller radius be safer? The surface speed on the outer edges of a smaller blade might slow down the missles, and I thought a finer blade without the protruding inserts might not catch the material.
A.
What causes kickback is a saw that isn't adjusted correctly or a blade that is beginning to wobble. There has been a lot written about this. You need to try a new blade--if it still happens, then it is saw alignment. Heat is often what happens with improper alignment and then the heat expands the blade and causes the blade to warp and wobble.
You will notice that if the saw protrudes above the work only a fraction, there will be less kickback.
A good saw shop should be able to provide more information, or check with some of the technical magazines--Fine Woodworking, etc.
Professor Gene Wengert is Extension Specialist in Wood Processing at the Department of Forestry, University of Wisconsin-Madison.
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