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Re: Why Is This a NO-NO or Is It?
Posted: Sun Nov 20, 2016 2:05 pm
by JPG
A sled is 'off topic', but I grasp both ends when using a sled. Move both ends after cutting prior to retracting the sled also.
Re: Why Is This a NO-NO or Is It?
Posted: Sun Nov 20, 2016 2:35 pm
by reible
Well for me it is quite simple. The image on the left is a NO-NO. Let me add that using a miter gauge in that case and using the fence as the control surface is also a NO-NO. If you want to check out the PTWFE I believe they cover this.
In the case where you want to use a miter gauge and control the length using the fence you add a block to the fence and the block must not be in the cutting zone, so when the wood enters the cut the block is no longer in use.
When you want to use the rip fence along then the aspect ratio of the wood needs to be such that you have a large contact area on the fence. At the very least this would be 6" on a small piece and at least 8" on a bit larger piece and 10" or so on a bit larger piece. Big pieces you need even more width on the fence. Numbers here are generic as each piece will vary with how it feels and works.
A very old rule is not to trap the work piece between the blade and the fence. A very good rule. Yes you do that when ripping and that is why you worry so much about kick-back. At least at that point you can take some reasonable actions to control it but stick a long narrow board and try to free hand it you are in the danger zone.
If you have more questions check out the bible, I'm pretty sure this is covered pretty well.
Ed
Re: Why Is This a NO-NO or Is It?
Posted: Sun Nov 20, 2016 2:39 pm
by charlese
In your left depiction of a cross cut, the right side is "dragging" on the fence. The term dragging only means the board is firmly touching the rip fence. This situation allows for a kick back of the small piece - or the entire board - if a small discrepancy like a board twist, or a mis-aligned fence, or a mis-aligned saw blade presents itself during the cut.
Another cause of kickback or jamming can happen is the board is narrower that the distance between the front and the back teeth of the saw blade. In this situation, the cuttoff will become free between the fence and the narrow part of the blade. (a bad situation) Yes, this cross cutting practice is a NO! NO!
If one chooses to use the rip fence to set the size of a cross cut, it can be done by inserting a block between the rip fence and the workpiece. Then the block should be moved back toward the front of the table far enough so the workpiece will pass the block just before entering the saw blade. I use this technique frequently.
Re: Why Is This a NO-NO or Is It?
Posted: Sun Nov 20, 2016 3:54 pm
by Ed in Tampa
I would not make either cut without a splitter.
I was always taught not to use the fence unless the piece of wood was a least as long as the blade was wide. Shortest board used with fence and 10 inch blade is 10 inches. Usually only about 4 to 6 inches of the blade width is exposed so you have a few inches of board that is not near the blade to control the board with.
Again no splitter no cut on my saw!
Re: Why Is This a NO-NO or Is It?
Posted: Wed Nov 23, 2016 9:51 am
by edski
Rule of thumb: When using a rip fence, always place the long side of the piece to be cut against the rip fence.