Aligning table saw -- how close is close enough?

[Roy Smith]

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?

[RB]

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:

[CW]

If it is truly aligned, the blade type isn't going to make any diference. What you are (should) be doing is aligning the arbor perpendicular to the miter slot.

[CW]

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.

[Bob Davis]

I thought what he was saying was the Forrest blade was more true than his other blades. I could believe there are differences.

Bob

[B a r r y B u r k e J r .]

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

[RB]

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:

[Edwin Pawlowski]

[Charlie Self]

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.

[Doug Miller]

That's a lot. I have the TS-Aligner Jr also, and mine is within 0.001" of parallel.

Not with a good blade. According to Forrest, their blades have total runout of

0.002" or less.

Better still to be dead parallel IMO, but not a big problem.

No, they're not close enough IMO -- particularly given the high-precision alignment tool that you now have. If you have a decent saw, it should be possible with very little effort to get your miter slots parallel to the blade within two or three thousandths, and likewise the fence.

You won't produce results that are any more accurate than the accuracy of your setups.

-- Doug Miller (alphageek at milmac dot com)

How come we choose from just two people to run for president and 50 for Miss America?

[Mike Hide]

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

[Bob S.]

Ahhhhhh jeeeeesh Ed.........give the poor troll a break....;-)

Bob S.

[Leon]

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.

[Leon]

The simple answer is, are you happy with the results of your cuts? Unless you measure the blade to miter slot properly you probably need not bother at all. Doing the measuring properly by the blade tooth will also indicate if the blade needs attention also. I try to take that tooth measurement set up more than once to verify the blade is not part of the problem. Anyway the tooth measurement generally sought after is in the .003-.0001 range. I seldom measure the fence setting. I simply cut a piece of wood and look at the results. If I don't like them I adjust the blade according to the results.

[RB]

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

Le>>That's true, but my experience is that the Forrest blades are extremely

[Michael Baglio]

What does Forrest charge for their services?

Michael

[Leon]

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

[Michael Baglio]

Michael

[Bob Davis]

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

[WebsterSteve]

Listen to Leon. His is the only good answer you got. Judge it by the results of the wood you've cut.