Wednesday, September 17, 2014

V5.38 - Table Saws: What’s Kick-Back?

So where does all the talk about FSBT leave us? Right back where we were…simply saying that new technology is good ; however, if one will USE the guards that have been part of table saw equipment since the 1930’s, one will avoid injury. Just as a side note, one of the other things that the engineers noticed with the Sawstop FSBT feature was that they felt it would encourage users to leave their standard guard off the saw. ‘After all, you now have this great flesh-sensing safety device that stops you from cutting your finger off’. Well, it’s my understanding that Sawstop still furnishes a standard guard with its saws AND they intend for you to USE it. Even THEY will acknowledge that use of a standard blade guard will prevent contact with the blade. Amazing how that works isn’t it? Truthfully, the FSBT safety device is merely another layer to help prevent injury. Sort of like seat belts AND airbags. Seat belts DO save lives, if one will USE them. Add airbags to them and you have another layer of safety. But ask yourself, would a car maker sell you a car that ONLY had airbags… and if they did, would you drive it?  I’m thinking… not.

Bottom line: USE the guards and safety devices that are supplied with your unit. Life will go well with you.

Ok, so back we go to our discussion of table saw fences. Some fences have a ‘micro-set’ adjustment knob that allows very small, controlled adjustments. In all cases, it is very important that the fence does not pinch the workpiece between itself and the blade. If that happens, the subject of ‘kick-back’ could become very familiar to you.

But since we’re on that subject, we might as well define it. “Kick-back” is a condition wherein the workpiece is grabbed by the blade and shot forward –TOWARD THE OPERATER- at tremendous speed. When kick-back happens, it is not something you can dodge…well, not unless you are The Flash and are used to moving at supersonic speeds. I knew an engineer in Jackson, TN who did some very in depth studying of kick-back – even to the point of doing some hi-speed video of what happens as the blade grabs the stock and flings it back toward the operator. It was really incredible to see. The stock usually came flying out in a circular motion which produced an arced gouge in the surface of the piece. The blade deflected so far that you would have thought it would shatter, but it didn’t.   

Kick-back is not something to want to see. I’ve seen many a cinder block wall get some wood imbedded into it by kick-back. It isn’t pretty. Just guess how bad it hurts to be hit by it.

Till next time….

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