New video: Sliding Table Alignment

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Hi Tim, wrote:

I'll have you know that those knuckles have been certified tracable to NIST standards! ;-)There is no "trial" of the fence setting in the video. Just measurement during an adjustment process. The "trial" comes when you make the test cut with the machine. The error is reflected in the accuracy of that test cut. There is no error if there is no inaccurate test cut.

Lots of trial and lots of error Tim. Let's see here, the first five test cuts all have error. Then you make a measured adjustment and five more test cuts with error. This "calibrates" your adjustment process. So, then you make your final adjustment and another set of five test cuts (not "One more test cut") and only after all 15 test cuts is "Bob yer uncle". I'm not saying it's wrong. I'm not saying it's inaccurate. I'm not telling anybody to avoid it. I'm just saying that I don't like it. It's not something that I find productive.

That's very good.

I'm sure that with a little math you could figure out the exact spot to put the indicator. This provides you with a predictable mechanism to use for monitoring the adjustment of your fence. But, you would do one better to have a mechanism to monitor the actual setting of the fence (it's actual angle). That's what you get when you use the square with the dial indicator. Direct feedback on how close the fence is to 90 degrees.

He probably went to a very hot place for lying. There is nothing on a contractor's saw which is stable to 50 millionths. Nothing. There are people who buy these low cost digital indicators which can read to 50u" and suddenly they become a Metrologist and all around expert on machinery setup. Don't you believe it!

Not bad. You see me do it real-time in the video. No CGI; no cuts, no time lapse video, and no stunt double. How long do you think that is? The whole video (all three procedures) is less than 5 minutes (4:66). Squaring the fence took about 2 minutes and I was deliberately going slow so that people could follow what was happening.

Sure enough. Yep, I'm sure it would work. But, if you're already going to do 2 or three iterations of the adjust/check cycle, then the extra effort doesn't really save you much.
What I show in the video is a procedure which is easy to understand and follow for those who haven't done it before. "Step 1, step 2, step 3, repeat as necessary, etc." However, after a while you realize that you don't really want to bring the indicator back to zero. You actualy want to go a little bit past zero. And, with a little practice it can be done without much thought on the first adjustment. But wait! The real expert discovers that the change in reading on the indicator can be slowed and even halted by adjusting the fence while it is moving. I do this all the time. There's not even a real need to establish a reference (set the indicator to zero). So, for me it's just too much bother to try and quantify the amount of correction needed in the fence angle. I just do it.

No problem. I'm just saying that it's not free.

Try it with a smaller square. All woodworkers must have a square, right? Like I said, 0.001" at 6" is the same as 0.003" at 18" - or 0.004" at 24" which rivals what you described above.

Not quite.

As you can see from the video, I have the large Excalibur. It also has the rotating stop but I just don't use it. Too many things go wrong with stops. After a few years in the machine shop, you learn to check everything all the time.

Stops and lines are great for quick and rough setups. But, when I need something to be accurate, I trust my square and indicator.
Thanks, Ed Bennett

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