duncsuss

Thanks -- my original jig was far more complex, it allowed the gauge to slide in and out, and of course it broke the first time I tried to use it!

The Delta repair man stressed the importance of keeping the miter bar to one side of the slot or the other, so I was careful about pressing down and in towards the blade. I tested both dots just in case the tooth was set, it seemed to give the same result as the one at the bottom of the gullet after scaling for the additional 1/2 inch radius from there to the tooth tip.

I checked with the blade at 45 degrees: there is a very small difference from the 90 degree blade setting. I'll double-check and reset the end stops for 90 and 45 blade angles, then check the blade again with the gauge to see if it's still less than 0.001" difference front/back tomorrow.

Hopefully I won't have to get into shimming.

Duncan

M1911Bldr

If you're seeing .001 or less difference between 90 and 45, you're done! Adjusting the stops is only going to make your cuts more accurate, it's not going to change the difference you see. If you were to tilt to 22.5, you'd see half the difference as at 45, etc, etc. You're measuring how close to perfectly parallel the table surface and the blade tilt axis are to each other. As long as you are REALLY at 90 degrees and read .001 or less between the mitre slot and blade, the angle you use to read the mitre tilt difference doesn't really matter. 45 deg just gives you max deflection and max "error" if there were any. I would cut some thick (3 or so inches) and check the actual cut for 90 degrees with a VERY accurage square. Have you figured out how to check your mitre guage for square with your dial indicator yet????????

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duncsuss

Are you suggesting this as a way to check blade/slot alignment or the blade 90 degrees upright?

I hadn't even thought about this being a possibility ... If I had a magnetic lock-down, I suppose I could clamp the gauge to the table top and push a builders' framing square across the table with the miter, testing the side deflection.

But that's probably not what you had in mind!

I do most of my cross-cuts using a sled (I built it as my second project after receiving the table saw, got the plans from a website). The fence slides around and locks down using T-track, and it has a T-track itself for clamps to hold the workpiece and a sliding stop for repeat cuts. I use a framing square to check the fence is 90 degrees to the edge of the sled (which was cut by the blade). I have a few useful angles marked on the sled

Thanks for the continuing education --

Duncan

M1911Bldr

to check your blade's 90 deg setting. Using a cut piece will eliminate any possibility of the blade causing an issue. I keep machinist's squares and triangles for checking tool setups. They're SUPER accurate and I only use them for checking machines. You can set your square against the face of the miter gage and run it along the dial indicator. Just retract the blade and use your jig. Doing this will get your mitre gage square to within .001. I know I'm talking "picking gnits" but I can depend on my machines being VERY accurate and all my joints being glue ready. I also set my jointer knives using a dial indicator. The knives are DEAD EVEN with the outfeed table. The cuts are so good, if I leave a jointed piece laying on the table for a minute or so, you can feel the suction as you go to pick it up!!!

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Measure with a micrometer, mark with a chalk, cut with a chainsaw!
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duncsuss

Of course -- the table has 2 miter slots

Thanks for all this very helpful information, it's so much easier to get somewhere when there are folk pointing out the best way forward.

Regards,

Duncan

cabinetman

Thought I'd chime in here with my ongoing dribble. I've never used a runout gauge to check a blade. My methods are pretty simple in aligning the fence to the blade. I use simple measuring devices to get the fence parallel to the blade. My first check is to make sure that the blade is parallel to the miter slots.

I use no toe in or out to the blade, and have never bothered with any measurements that were in the "thousanths". Woodworking is not machine shop tolerances. I get no "burning" or inordinate "sawmarks". Believe it or not, I get pretty accurate cuts. Could be I've just been lucky all these years.

woodnthings

Close enough is close enough? Beyond that, too close is not necessary? Achieveable but to what end, maybe personal satisfaction? To each his own I guess, but my table saw set ups are done without the dial indicator.
BTW, Another way to check for cross cut being square is to make a cross cut on a 10" wide piece, flip the board over and make another cut, if they are not parallel, you are off by half the difference. Sneak up on it and adjust, try again. bill

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duncsuss

I understand what you are saying. If I had years of experience, I probably wouldn't bother with all this stuff either.

My other hobby is photography, and I have friends who can shoot a camera without using a light meter and still get perfect exposure because they know what's right just by looking at it. Me, I need to use a light meter -- but I'm slowly learning and slowly getting better at guessing.

I hope it won't be long before I can feel whether a tool is tuned properly or not instead of having to measure it. As for the measuring instrument -- well, I use a dial gauge because I know how to read one. If I had the confidence to use a simpler instrument (which would require my judgment as well as the tool), I'd probably use one.

Duncan

GeorgeC

Since you are aligning your to blade to slot with an accuracy of 0.002 or 0.003 I assume you are also measuring your wood cuts to the same accuracy. What tool do you use to get this accuracy?

On my saw I could not possibly get the fence that close to parallel to the blade on each new cut.(I think that in the real world the fence to blade dimensions are what really count unless you are using a miter guage or sled.) When I set up my saw for a cut I measure from the front of the blade to the fence to set the size of the cut. Then I lock the fence and again check the front measurement and also the back of the blade measurement. I always want the back of the blade just a hair further from the fence.

This is presuming that the runnout on the blade is within tolerances.
This I also check periodically and each time I install a new blade.

G

M1911Bldr

If you have a dial indicator and are setting up your machine, why not use it? This isn't a daily occurrence, but a good, quality, sound, accurate setup of a "new" tool. As long as you have the wherewithal, use it.

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Measure with a micrometer, mark with a chalk, cut with a chainsaw!
Cut to print, grind to fit, paint to match.

woodnthings

Don't think that your suggestions were not much appreciated. Not the case. The extreme precision types here, probably with metal working and machine set-up experience, will certainly have an interest and by introducing these techniques you have expanded the
concepts for others of us I for one would appreciate a photo explanation of jointer set-ups and planers, since the blade settings on these require more precision than simple measuring tools can provide. I have been using the stick/shift technique myself but don't have a feel for the accuracy of this method. Could you possibly post something along those lines? bill

Attached Thumbnails

__________________
Never stand directly in front of a horse or tablesaw that's running!
If you're not making dust, you're gathering it. After I reread my own posts, I agree with myself even more.

M1911Bldr

is to use a manufactured fixture such as: http://www.oneway.ca/workshop/multi-gauge.htm. The insturctions on the webpage go for all indicator setups, however you hold them. I use a magnetic base for all my setups. If you already have a dial indicator, you can get the multi-guage without one and use your own. You'll need a flat foot on your indicator - you can get them in "indicator point sets" at all the usual places for less than $10.00. If I were just starting out, I'd buy the multi-guage and be done with it! I don't "cut-to-length" using dial indicators, but I do like knowing that all my cuts, joints, planed surfaces and the like - even resaw work - are as accurate as they can be and the tool isn't an issue! I set my tablesaw up this way about 3000 cuts ago and it's still square. I actually checked it the other day just to see - took 4 minutes, total - and it hasn't moved AT ALL. If something doesn't fit, I know it's that guy running around in my shop (me) doing something wrong. I haven't sanded or tweaked a joint to fit since I set things up - even on 10-sided picture frames. I hope your test bar doesn't have that tape going all the way around it- you're introducing at least .004 of excess blase height! If you keep your drag distance to 1/8 or less, you'll be within .001 of the knives and table being equal. You did sand the edge of your test bar dead flat............?????

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Measure with a micrometer, mark with a chalk, cut with a chainsaw!
Cut to print, grind to fit, paint to match.