Aligning table saw -- how close is close enough?

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My Table Saw Aligner Jr. finally arrived the other day. Today I put it on the saw and took some measurements.
The blade is 0.01 (10 thou) out of parallel from the miter slot, measured from the front to the back of the blade with the blade raised all the way.
I just measured the blade plate. I know you're supposed to measure the same tooth front and back, but it's really difficult to move the blade by hand and have it end up in the right place because of the belts. Is this really a critical issue?
The fence is 0.02 (20 thou) out of parallel from the miter slot. The back of the fence is further away than the front (which is the better direction to be out by).
At these "close enough"? Are they worth worrying about to try and get better or will I just end up chasing a level of precision that's not practical to achieve?
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If the fence and blade skews are in the same direction you could be off by as much as 1/32" over 7 or 8 inches. To me this is too much.
I was able to get my WW II blade parallel to the miter slot within +/-0.0005". (I can't do that with non-Forrest blades though.)
My Unifence diverges from being parallel with the miter slot by about 0.004 at the back of the blade when compared to the distance away at the front of the blade.
Happily, when I re-check I find that there is no measurable movement over time.
RB
Roy Smith wrote:

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What you are (should) be doing is aligning the arbor perpendicular to the miter slot.
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I thought what he was saying was the Forrest blade was more true than his other blades. I could believe there are differences.
Bob

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That's true, but my experience is that the Forrest blades are extremely flat, my other's aren't. I just got a couple of Freud blades back that I sent to Forrest to have sharpened. I'll see how these perform now. They were not flat before.
RB
CW wrote:

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RB responds:

Well, another point: when you try to use blade plate flatness as a basis, what happens if the arbor flange is a hair off in one direction or the other? The blade may be perfect or as close as possible. If the flange is off, you're still screwed.
Of course, all of this should start with a check of flange flatness (feeler gauge and an accurate, short straightedge), arbor washer flatness, and arobor run out. Do that before you start fooling with blade to miter slot alignment and fence alignment. You can, if you wish, buy specific measuring plates of a guaranteed flatness to help in the latter stages. But the best way still is to mark one tooth, put on a good, sturdy glove and MOVE that thing front or back as needed. After all, you will be working with that blade, so getting things accurate with that blade is sensible.
Charlie Self "We're 269 days from the election, and that's several political lifetimes." TERRY HOLT, Bush campaign spokesman.
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Umm hopefully when you sent your blades to Forrest to be sharpened that you also requested that they be brought back to factory specs as sharpening alone does not flatten a blade.
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Yup. Forrest does a good job. I just tell them to do whatever it takes to bring them up to spec. They don't do anything that doesn't need to be done.
RB
Leon wrote:

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What does Forrest charge for their services?
Michael
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Typically Forrest is very competitive for sharpening IIRC To simply resharpen my 40 tooth WWII, $20. To bring the flatness back to factory specs, sharpen, test cut, and return shipping the cost was about $37.00. Take a look here http://lib1.store.vip.sc5.yahoo.com/lib/forrestman/carbide-sharpening.html
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On Sat, 07 Feb 2004 18:03:37 GMT, "Leon"

Great link, thanks.
Michael
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I looked at using their service but the shipping ran the cost out of bounds. Of course I live in the nasty old big city. That does have the advantage of competitive and abundant availability of everything. We get excellent sharpening service for $16 and of course, no shipping.
Bob

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I thought that the Shipping was a bit strong also but, My local service in Houston is not a slouch. They have computerized sharpening machines that even recognize a blade that they have sharpened before. While I thought that they did a good job for the many years that I used them, I was unhappy with the results. The blade cut more quickly but the cut was also more rough than before they resharpened it. They sharpen to 600 grit IIRC. I used the blade for 2 months and then tried to tilt the blade while it was elevated in the zero clearance insert... ;~) Don't do that. This time I sent it to Forrest for sharpening, to bring it back to factory specs, test cut, and to ship it back for $17 more than the local shop charges to just sharpen. The blade cut like new when I got it back. IMHO the Forrest service is the best and worth the extra for shipping.

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Hey, Leon, I'm in Houston, too! We should compare notes. I drop my blades off at the Cutting Edge. I'm pretty sure they sub the work out to MVP Sharpening. Is that who you used? I swear my 50T freud was better than new when I got it back. I've not let them have a go at my WWII yet, but its so new that it has not needed resharpening yet.
I know what you mean about tilting the blade. :-)
Bob

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Yeah Bob, The Cutting Edge is or was sending off to MVP.. I have been using MVP since the late 80's when they also sold power tools. They do a good job but Forrest whips them IMHO. I will say however, there could have been a slight problem with my Forrest when I took it into MVP but still I think the quality of cut was not as good after sharpening. Unfortunately MVP does not or did not flatten blades at the time. I believe that checking for flatness and reflattening if necessary should be done while being sharpened now. The blade cut good as new again.
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Thanks for the feedback. I'll keep that in mind when its time to sharpen the Forrest.
bob

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Yes. Just measuring the blade plate, you have no way of knowing if what you are measuring is arbor alignment, blade warp, flange alignment or a combination of all three. I have never tried intentional misalignment to find out how much is to much but Ed Bennet recommends .005 or less. I would imagine that he has tried it.

If this was measured over the entire length of the fence, I'd leave it alone. If it was measured over the length of the blade, I'd get it closer.

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Yes! What if one tooth you chose is bent,a nd another isn't? Also, some blades have more set in the teeth than others, choosing different teeth on opposite set sides may mess you up. If you use the same tooth, it dosen't matter.

How does it cut wood? That's my final measurement, and the one that really counts in my opinion.
Barry
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:

--

It was pretty dumb of someone to come up with a measuring method that is so
difficult. Life is tough enough without having to choose and mark a single
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I already did that and he said they would set up a committee to evaluate the problem, failing that he will call for a full house vote on the floor whether or not to take the matter under advisement. mjh
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