How much runout on TS is too much

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wrote: .

Exactly and as I mention in another post, I seldom need to address cut edges other than to bring them to the same smoothness as the other project when sanding.

Snip
LOL, "definate maybe", the earliest that I recall using that comment was in the Fall of 1972 when speaking to the store district manager. I was in my first year of college and the "definate maybe" answer to his question brought a "College Kid Answer" from him. ;~)

LOL, Ed I was just seeing if you were paying attention. ;~)
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Good idea. Like cherry, maple is prone to show scorch marks and any closed grain wood will make blade marks more obvious.

That will do the trick for blade and fence alignment.

I'm wondering why you think the alignment is this close. See my comments below.
Is the "Ray Vojtash" of the Wood Mag article the same as "RayV" of this posted message? I'm not sure why you think the technique is special or better than any other "feel the rub" technique. It doesn't matter if you hold the stick (or bevel gauge blade) against the miter gauge or screw it onto the bar, it's the exact same technique.

It is a bit high, but not outrageous. It's probably not the silver coating on the blade (unless this coating is thick paint). This brings up the alignment question I mentioned above. How can you be sure of your alignment accuracy when the blade runout is three times higher? Did you mark a spot on the blade and make all your measurements on that spot (rotating the blade)? Or did you just run the indicator stylus along the surface of the blade?

Yes. In general, anything less than 0.005" is good enough. I've done a lot of testing with various blades and woods. Even with magnification, I could not detect any improvement in the quality of the cut surface for alignment error below 0.005"

It means that your cut surface will have ripples in it that are 0.003" deep. The size and shape of these ripples will depend on how high you raise the blade and how fast you feed the stock. This sort of defect can easily be seen and felt on exposed surfaces so expect it to require some extra cleanup. Good quality modern glues don't generally have any trouble filling 0.003" gaps between mating surfaces.
You need to determine if this runout is due to blade warp or an arbor/ flange problem. You can easily use your setup to check both the arbor and the flange. You will want to tilt the arbor so that the dial indicator can meet the surface of the flange at 90 degrees. You will want to leave the arbor at 0 degrees to check arbor runout. Hopefully there is a spot along the surface of the arbor where you can avoid the threads. You should see less than 0.001" runout on both of these.

The best practice is to keep the dial indicator plunger at 90 degrees to the surface being measured (zero degrees tilt). When the dial indicator is tilted at an angle it introduces error into the reading. The error is going to make the reading look higher than actual changes in the surface being measured. It will also exaggerate any instability in your dial indicator fixturing.

You can calculate the actual geometry from the dial indicator reading. It is equal to the dial indicator reading times the cosine of the tilt (away from 90). The cosine of zero degrees is 1 (best situation). If you are tilting your indicator by 30 degrees, then multiply your readings by 0.86 to see what it would read if there were no tilt.
Tilting the indicator is a better alternative than using one of those flat blade replacement plates. Apart from the monetary savings ($40 or more), and the time you save not needing to swap out your blade, you won't be introducing a reference surface with unknown errors. The specs on one popular plate seen in catalogs and online are +/-0.003". You could think that you've aligned your saw properly when all you actually did was align it to match the warp in the blade replacement plate.
Feel free to ask questions.
Ed Bennett snipped-for-privacy@ts-aligner.com
http://www.ts-aligner.com Home of the TS-Aligner
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sure is.

yes
That makes sense.

I'm going to check it by rotating the blade and then checking the arbor and flange. I suspect that this $30 blade is warped because when I've ripped with a good 80T blade I've nearly finish ready surfaces.

Thanks. I'll see if I can modify my jig to get it closer to 90deg so I don't need to look for my calculator.
The indicator I have does have a pin 180 from the working end but I would have to grind the lug off of the back to make using that worthwhile. I might be able to get the back lug to go below the table if I measure from the left side of the blade.
Your point about the blade runout equaling depth of hash marks on the wood makes sense to me so I will investigate that further. Thanks Ed.

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<snip>

<snip>
Looking at your site just made me realize that I don't need the indicator near the table to check blade runout. I can do that up high. I just need to get it close to 90deg near the table to check my alignment.
Thanks again.
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wrote:

I also check the blade for parrallism to the miter slot with the blade all the way out ( but not on the stop) and down as far as you can and still get a measurement. The main thing is to not have the blade cut wood on the back side at any depth of cut .
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Verata Nictu? Necktie?
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Followup:
Returned the 'Silver' coated Avanti blade and ordered a 50T Frued Diablo. Probably not as good as a WWII but half the price. I am also very happy with the 80T Diablo I have, cuts great and will easily rip 3/4" Maple even though it is not made to do so.
Checked the runout on my arbor, barely perceptible ~0.00015. Good.
Checked the runout on the flange and at first it was ~0.0015! Then I noticed that even touching the belt caused the needle to jump (contractor saw). So I took the belt off and the flange runout is ~0.0003 after a little touch up with emery cloth, good enough for me.
Put the original 28T Jet blade on that made maybe three cuts in its life and the blade runout was 0.005! WTF? Spun it 180 and now the runout was 0.001. Spun it back and runout was 0.002? Took the blade off to see that it was scratched/smutzed up. Emery clothed it and now the runout is around 0.001 in any position (without the belt). I'm satisfied the saw is OK and the Avanti blade was a POS.
OK, so is all this checking worth it? I think it is, it takes maybe five minutes to check the runout of a newly mounted blade. Well worth it to find out that an errant wood chip got stuck between the blade and the flange making a smooth cut nearly impossible. I plan to keep the dial indicator in a much handier spot. That way I can check a blade that has been lying around for a year with an Allen wrech under one side and a stacked dado set sitting on top of it ;-).
Enough measuring, I need sleep so I can make some sawdust tomorrow.
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Do any PM 66 owners here know the tolerances of their saws? I aligned my humble Delta contractor's saw with that jig, and it cuts easier than any 66 I've ever seen. I think I got the blade parallel to the slot to within 0.002".
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I don't happen to have a PM66 handy right now, but I'm very familiar with it. It's a fine machine. I wouldn't mind trading in my Unisaw for one. I wouldn't trade one for any contractor's saw. If it isn't aligned properly, the best table saw can perform much worse than an everyday humble contractor's saw. I know for a fact that there are a lot of real cheap junkers out there outperforming high end cabinet saws. Alignment does make a difference.
When I look at comparative reviews of machinery, the first thing I look for is a description of how the machine was prepared. Most reviewers ignore alignment completely. Some check the "factory" alignment in a misguided (ignorant) attempt to judge the quality of workmanship. I don't think I've seen a reviewer pay attention to setup and alignment since Kelly Mehler's table saw review in the April 2003 edition of Woodworker's Journal. You can't make valid comparisons between two machines until they are both properly setup and aligned. Glad to see that Kelly understood this - wish more did.
Ed Bennett snipped-for-privacy@ts-aligner.com
http://www.ts-aligner.com Home of the TS-Aligner
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The 66 is a great machine, made for shops that turn it on at 8 AM and off at 5.

I aligned my Delta for safety, with the rear trunnion bolts upgraded to PALS brackets. Improved cut quality is a welcome side benefit.
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wrote:

An insulting and misleading statement. Leads the reader to consider that there is no basis for quality judgement and comparison from the alignment done on the assembly line by the manufacturer.
The truth is unless the component parts are just terrible, all saws can be "set" to very close to zero at 90 degrees and I suspect that most manufacturers have assembly procedures that achieve that using rather sophisticated set up tools. I know one does at least. As the blade is tilted, it is exactly the "quality of the workmanship" of the component parts that determines the reading at 45 degrees and the difference between the two figures is an excellent indicator of the quality of workmanship when comparing different units. The flatter the table, the more parallel the boss plane to the top, the flatter the cabinet top plate plane, the more accurate the trunnion/brackets, yoke assembly and arbor assembly, the closer that 45 degree figure will stay to zero out of the box. While there are certain things you can do to offset the tolerance stackup of some of those parts if others are bad "you got what you got".
Frank
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I don't know why anybody would take offense Frank. I really don't think it's reasonable to expect a machine to maintain proper alignment after riding around on forklifts, trucks, and rail cars. The vibrations and thermal changes virtually guarantee that alignment will be lost during shipping. If I were personally responsible for aligning and testing table saws at the end of a production line I would not be surprised or offended to learn that 99.9% of the machines that I so carefully aligned arrived completely out of whack. It's just physics. My Unisaw needed alignment, and it came with a bunch of "shock watch" tags on it.
I think a manufacturer cannot verify that a machine is defect free until they properly align and test it. And, the quality can be clearly judged inferior if a machine cannot be properly aligned. But, the state of alignment as delivered "out of the box" is pretty much irrelevant.

I agree, there are certain aspects of alignment (like the tilt axis parallelism to the table top that you mention here) that are dependent on quality of manufacture. It would be incredibly easy (and inexpensive) to implement in-process 100% inspection of every single casting that gets machined. And, the use of the Meehanite casting process would significantly reduce (eliminate) post machining warpage. I suspect that only an exceptional manufacturer would do such things. And, if they really did, then I would expect that none of their saws would require shimming under the trunnions or between the base and the table (or, such a small number that you would just never hear about it).
Having heard of this problem from owners of all the most popular brands, I suspect that they really aren't doing anything substantial in this area. My 80's vintage "Proudly made in the USA" Unisaw needed shimming (among things) before it would operate properly. So, whatever Delta did before shipping my machine, it didn't help much.

This might be how I "got what I got" with my Unisaw. If the tolerances stack up so that the product (when fully assembled) can not be properly aligned (without shimming, filing, or other modifications), then any mechanical engineer will tell you that the manufacturing process is poorly designed. Tolerances are *supposed* to define the range of variability for which no defect can occur. Unfortunately, too many manufacturers define their tolerances as the range of variability for which an affordable amount of warranty expense occurs. I'm in the "zero defect" camp, not the "acceptable warranty liability" camp - which never made me very popular with the bean-counter types. They were always glad that I only did the numbers, not the decisions.
Ed Bennett snipped-for-privacy@ts-aligner.com
http://www.ts-aligner.com Home of the TS-Aligner
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wrote:
<all snipped>
My mistake Ed. I should have assumed you would not see the offense. But the mistake was mine. I should never have reacted. It offered you another chance to extend your not so subtle spam campaign. Won't happen again.
Frank
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I still don't see it Frank. Why don't you explain it? The comment wasn't directed at any particular person, company, or machine. It was a comment about some who do machinery reviews without any technical expertise. Did you author such a review article?
Why does a guy who proudly declares that he has never checked the alignment of his saw get offended when someone says that it's pretty ignorant to judge the quality of a machine by the accuracy of it's factory alignment?
Why does a guy who says "just make sawdust" to someone who wants to correct misalignment in their saw get so offended when someone says that it's pretty ignorant to judge the quality of a machine by the accuracy of it's factory alignment?
I think my Unisaw is a great machine. I have been real hard on it for about 20 years and it's still amazingly accurate. I didn't expect it to be well aligned "right out of the box" and it wasn't. If I had been so misguided, I might have concluded that it was a poor quality machine. That would have been a big mistake on my part. Ya, it took some filing and some shimming to get it fully aligned but It was a one- time event so I didn't make such a big deal out of it. I share that info here with the hope that I can steer others clear of making such an ignorant misjudgement of quality.
If there's real cause for offense, then you know that I will appologize - and it won't be one of those backhanded "...if there was something I said.." BS appologies. And I'll do it without any expectation of reciprocation (in spite of the "spam campaign" comment, which was intended as an insult).
Just explain why you are personally insulted when someone says that the quality of a machine should not be judged by the accuracy of its factory alignment.
Ed Bennett snipped-for-privacy@ts-aligner.com
http://www.ts-aligner.com Home of the TS-Aligner.com
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: Just explain why you are personally insulted when someone says that : the quality of a machine should not be judged by the accuracy of its : factory alignment.
And more to the point, the accuracy of its factory alignment as affected by its post-factory experiences being shipped across the ocean and loaded/unloaded on any number of conveyances. Then hauled into a shop, uncrated, and possibly rolled around out of its crate during assembly.
    -- Andy Barss
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I think you should has said "alignment when received by the customer."
In Frank's case, the poor alignment was not the fault of the factory, which Frank was personally involved with. Yet your phrase appears to place the blame squarely on the factory.
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Hmmm... I suppose I can see your point...sort-of. I have been using "factory alignment" interchangably with "out of the box". I didn't think that there would be any confusion - especially since I explained in great detail how the factory alignment gets disturbed. And, since I also explained why factory alignment is important (to properly test the machine) I'm still left wondering how he could have taken offense - especially since he's made it pretty clear that he thinks alignment is not worth bothering with.
I pretty much want to stick to the statement that Frank quoted and find out why he felt that it was so "insulting and misleading". It was a commentary about people who do a poor job evaluating the quality of a machine, not on the company or the employees that produce the machine. Would he prefer that I conclude that my Unisaw, and the saws of 99% of my customers are low quality just because they didn't arrive with good alignment? I think that would be much more misleading and insulting (not to mention ignorant).
There really was no insult intended in my statement. I cannot imagine the connection between Frank and reviewers who judge a machine's quality by it's "as arrived" alignment. If he does take it as an insult to his work and the company that he works for, then maybe he should consider how his intentionally insulting comments have affected others.
Ed Bennett snipped-for-privacy@ts-aligner.com
http://www.ts-aligner.com Home of the TS-Aligner
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Ed Bennett wrote:

Clearly, because he interpreted as a dig at the manufacturer and has a long past with one which unfortunately, ended up quite badly. Nevertheless, he has a lot invested and can't let that go...
Just let it be, please...
--
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"dpb" wrote in message

The "Reality Distortion Machine", once started, must obfuscate, and insult with innuendo, ad infinitum. Thunderbird has a "blocked sender" feature ... use it and do us all a favor.
Thanks ...
--
www.e-woodshop.net
Last update: 10/17/07
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Ahhhh, smear politics.
--
NuWave Dave in Houston



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