Blade runout

**Uncle Cracker** · 09-08-2009, 06:17 AM

I don't know if .007" runout is "as good as you can expect", but it's not bad, particularly when you consider that it's a cumulative total of all the tolerances, eccentricities, and torques/flexes that go into an entire assembly.

You could try remounting the blade at 90 and 180-degrees from where it's mounted now, and see if this affects the runout slightly for better or worse. Mark the blade and the arbor, so you will know if the resulting runout follows the blade, or stays with the arbor.

**cgallery** · 09-08-2009, 06:51 AM

I try to shoot for +/- .002 (which is, I guess, about .005" total) or better. I have a few blades that do +/- .001".

I think .007" is perfectly usable. If you'd like to do better, I'd follow Uncle Cracker's advice and mark a relative position on the parts, and then try "dialing-in" (by rotating parts in relation to one another) a lower number.

If you can reduce the runout further, make a second mark on the components so you know how to reinstall them.

I have a top mark on my arbor, and marks on my spacers to know which side up, and marks on my washers to know which one goes on first, and which side is up.

I wouldn't have gone though all that except for the fact that I had started with a terrible problem and wanted to achieve some consistency.

**cabinetman** · 09-08-2009, 07:05 AM

If you have run out at the arbor shaft, there's not much you can do about it. I've had several table saws and never checked run out with a dial indicator. They are a pretty cool gauge if you're into gauges. Needing to know differentials in thousandths is bit moot IMO as we're talking about woodworking, not machine shop procedures.

UC's suggestions are good ones and are usually the ones used by heavy users of table saws. You can become aware of run out by what kind of edge is left by the cut, or noise, or vibration. With the saw unplugged, and making sure the power is off, you can raise the blade all the way up. Mark one tooth in the front right at the table level. Take a measurement to a fixed point, like the locked down fence, or a miter slot. Then rotate the same tooth to the back and do the same measurement from the same point on the tooth. Further testing could be to do the same test by using another tooth 90 degrees from the first one used. That will tell you a general story about the run out produced by that blade.

As UC suggested, another blade, or remounting the blade may reveal different dimensions.
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**Knottscott** · 09-08-2009, 07:10 AM

0.007" isn't that good for a precision blade....0.001" or 0.002" is more what I'd expect. Just to be clear, is this a Ridge Carbide blade or a Ridgid blade? You might consider exchanging it if it's new.

**rlah** · 09-08-2009, 09:20 AM

Thx to all for the feedback.
The blade I was using was the good Ridge carbide blade -- a very nice blade... I don't think it is part of the runout problem.

I don't understand cabinetman's comment about my checking the runout on the arbor... this is critical to a blade running true. Woodworking may not be "machine shop" practice, but woodworking machines definitely require "machine shop" tolerances. If cgallery shoots for .002" blade runout at the blade tip, that means tenths of thousands accuracy along the arbor, washers and spacers. Precision does matter, especially for furniture woodworking.

The point of my post was to share the experience of this fix ... a consistent reduction in runout from .022 to .007... it means I was on the right track. Has anyone else noticed burrs developing on the conical washers? I may buy new washers and spacers, but I think my fix restored the washer to a workable state. (I wonder where I can buy these parts now? I suppose I'll go to Craftman site...)

I will try UC's methods of turning the blade, spacers and washers to see if I can dial in a better reading. I'll try to post results if possible.

Again, thx to all... the experience level on this forum is why I come here. I've looked at other forums, some are OK. But it seems like this forum has the most top notch experience of any. How could a little table saw generate so much interest? Hmmm... come to think about it, I need to kick in to the Fund Drive for this year.

**pelligrini** · 09-08-2009, 09:33 AM

You might check the how much you tighten the nut too. I had read several discussions on this site about having the nut too tight.

When I finally got a dial indicator I found that I got less runout if I tightened it more than I was used to. YMMV

**cabinetman** · 09-08-2009, 09:38 AM

Originally posted by rlah

I don't understand cabinetman's comment about my checking the runout on the arbor... this is critical to a blade running true. Woodworking may not be "machine shop" practice, but woodworking machines definitely require "machine shop" tolerances. If cgallery shoots for .002" blade runout at the blade tip, that means tenths of thousands accuracy along the arbor, washers and spacers. Precision does matter, especially for furniture woodworking.

If you did measure runout on the arbor, there's no simple fix. Runout on the blade could be fixable and minimized. I probably have runout of some measurable amount, but using methods already discussed provides the kind of performance necessary to produce the high end furniture I fabricate.
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**cgallery** · 09-08-2009, 12:06 PM

Originally posted by rlah

I will try UC's methods of turning the blade, spacers and washers to see if I can dial in a better reading. I'll try to post results if possible.

One more thing you can do is tighten the arbor nut enough so there is no play in the blade, and the blade can spin while the arbor doesn't. This will allow you to check your blade itself for runout.

Also, if the flange of your arbor is out, there was a site somewhere where a guy documented his procedure for getting it flat right on the table saw. He essentially made a jig that held a stone and advanced it into a turning arbor flange. I can't remember where I saw it, but it was interesting. He basically took an unusable Delta contractor and brought it back to life.

**rlah** · 09-09-2009, 07:49 AM

cgallery:
I will probably include your "spinning blade" suggestion when I go thru further fine tuning. I suspect it will confirm that my Ridge blade is fine. I seem to recall you were the one who recommended this blade to me a year or 2 ago. And I'm happy with it.
I doubt the flange on the arbor has runout, especially since I measured so little runout at the threaded tip of the arbor.

pelligrini:
I tried tightening a bit more when I first found the problem but it did not seem to help. I think in general I've been tightening the nut just about right -- tight but not too tight. But I wonder that maybe 1 time I might have tightened it too much which might have caused the burr to form on the conical washer.

**cgallery** · 09-09-2009, 08:55 AM

Originally posted by rlah

I seem to recall you were the one who recommended this blade to me a year or 2 ago. And I'm happy with it.

Probably not me, as I have never tried one. They've got a great reputation, though.

**reddog552** · 09-09-2009, 09:50 AM

Blade runout

Just for kicks and gigges I put my indicator on .0018 runnout on the blade.this is the same indicator I use for trueing HD racing motors, 10,000s increments.

This is a brand new blade. I also have new spacers, Blade Washers & nut. Guess I good!!!

Attached Files

**rlah** · 09-17-2009, 02:28 PM

Quote from reddog552:
"....0018 runnout on the blade... I also have new spacers, Blade Washers & nut. Guess I good!!!"

That is good! Dumb question... where did you buy the new spacers, washers and nut? I have not bought replacement parts yet for my Craftsman 21829... and I'm looking to find my manual... where did I put it 2 years ago? Oh well...

**reddog552** · 09-17-2009, 05:49 PM

parts

http://www.ereplacementparts.com/ryo...7954_7956.html

Blade runout

Blade runout

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