Monday, May 23, 2011

Biesemeyer Fence Micro-Adjust

I love my Biesemeyer fence just as much as the next guy. It's solidly square, reliable, durable, and, well... it's just solid. But I got tired of doing little love taps with a fist, or my knuckles, or slapping it a bit, to try to move it just a smidge, or a hair, or some other nonsensical invented dimension that would work. I really needed a way to do small adjustments. I saw an attempt by Rockler to make a magnetic micro-adjuster, but all the reviews I read said it was junk and worth skipping. So, I did some head scratching, and I'm pretty happy with the solution I came up with.

I already have T-track inlaid into the extension table on both my SawStop, and my Delta contractor saw. I put it in at the recommendation of Jim Tolpin's book, as it helps with saving a fence position. (Bolt a block of wood to the T-track, snugged up against the fence, and you can always move the fence back to that setting.) I've also used the stop block to set measurements for long cross-cuts using a short miter bar. So, I put together this simple adjuster, using some all-thread, 2 wooden blocks, a knob, a threaded brass insert, and a plastic nut... which happens to be included with the packaging for the T-track.

The plastic nut is there to keep from scratching up the fence, but isn't entirely required. A scrap of wood would do. And in some cases, where the fence has to be closer to the blade, I need to use a block of wood to span the gap between adjuster and fence anyway.

The rod is threaded 1/4-20, which is 20 threads per inch. So, one revolution moves the fence 1/20 of an inch. (.05") And 1.25 turns gives 1/16".

The knob has 4 internal ribs and 12 external nubs. 1/20 of an inch, divided by 12 (moving one nub at a time) moves the fence 1/240" (.004") so moving from the peak of a nub to the bottom of the hollow between nubs is ~.002. I'm sure I could get more anal if I wanted to, but .002" is a pretty fine adjustment for a table saw.

Beyond that, if I want to get more precise I'll have to keep my saw blades a lot cleaner.

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