Table saw blade alignment - Lo-tech / Hi-tech

Good day

Well, it's almost spring and I started to "warm-up" the machines...well, table saw and router table...that's all my "machines".

I don't have all this expensive equipment to align the blade to the miter slot so, I used a "Lo-tech" method just to bring the blade as parallel as I can, to the miter slot. I call it "Static alignment"

In my opinion, all the "Hi-tech" (and Hi-price) instruments can be "super-duper" accurate but, I think that the blade itself "knows" better if it is aligned to the miter slot or not.

I call this check, "Dynamic alignment"...I just clamp a strip to the sled (or the miter gauge) and cut...when the strip reaches the back teeth, I listen to the noise...

If it's "cutting" noise, I know that I have to turn the blade clockwise.

If I don't here any noise, I know that I have to turn the blade counter-clockwise.

If I hear a "scratching" noise (I mean, the back teeth are just touching the strip) I know that the alignment is good.

Later, I check the fence alignment to the miter slot (Static check), rip some thin board and listen to the noise of the back teeth (Dynamic check)....and, same as above...

Actually, you can omit all the "Static test" and align the blade only by using the "Dynamic test"...especially if it's only minor correction, but the "Static test" will save some time and if you are lucky, the "Dynamic test" will prove good on the first time.

Regards
niki


http://i208.photobucket.com/albums/b...20align/01.jpg


http://i208.photobucket.com/albums/b...20align/02.jpg


http://i208.photobucket.com/albums/b...20align/03.jpg


http://i208.photobucket.com/albums/b...20align/04.jpg


http://i208.photobucket.com/albums/b...20align/05.jpg

And here is the "Dynamic test"
http://i208.photobucket.com/albums/b...align/03-1.jpg

Listen to the noise of the back teeth
http://i208.photobucket.com/albums/b...align/04-1.jpg


Bring the rip fence close to the miter slot and check the distances at one end...
http://i208.photobucket.com/albums/b...align/05-1.jpg


....And the other end
http://i208.photobucket.com/albums/b...align/06-1.jpg


Cut a test piece and listen to the back teeth noise...
http://i208.photobucket.com/albums/b...20align/07.jpg

I do the same also on the long fence
http://i208.photobucket.com/albums/b...20align/08.jpg


http://i208.photobucket.com/albums/b...20align/09.jpg


To check the squareness of the sled, I took a piece of thin board (floor panel)....
http://i208.photobucket.com/albums/b...20align/10.jpg


And cut it to 4 pieces
http://i208.photobucket.com/albums/b...20align/11.jpg


I alternate the pieces and checked them on a straight edge...any mistake will multiply itself...
http://i208.photobucket.com/albums/b...20align/13.jpg

Niki,

After having lots of problems with my alignment, I did a search and came across this thread. As usual, a neat and pragmatic solution!

I wonder if you have any idea of the tolerances your procedure results in? I keep reading postings where folks claim to be within one-thousandth, etc, and would like to know just what is within the actual realm of possibility.

Art

Thank you Art

First, I must admit that I learnt this method from reading the "Altendorf" slider operations manual and I believe that the German engineers know exactly what they are doing....as you know, we are talking about very expensive professional slider....

OK, lets start with the sled...IMHO, the accuracy of the cut depends solely on the Miter gauge fence setting...i.e. if the fence is set at exactly 90° to the miter slot - the cut will be exactly 90° without any connection to the blade-to-miter slot parallelism...

Of course if the blade is too much off-parallel we shell get "burns" or "pulling" but actually, the cut is done only by the front teeth of the blade.

I have my own method of setting the miter gauge to exactly 90° to the miter slot that I think, it's the most important setting....if the blade is within 0.0001" will not help at all to cut 90° if the miter gauge fence is out of 90°...

As I understood, the Altendorf engineers wanted to avoid or reduce the possibility of a kick-back and that's the reason that "You have to hear only a 'scratching' noise of the back teeth" - kind of a fraction of toe-out but still not to effect the accuracy...

Same with the rip fence that many people are "toeing-out" but, the above method gives the minimum toe-out that will not effect the accuracy.

As for the rip fence, as you can see, I'm using the "Short fence" (for solid wood) because, after the wood is cut by the front teeth, the cut is finished...the accuracy of the cut, depends only by the pressing force to the fence before the blade...

If I'll keep the wood pressed firmly to the fence before it enters the front teeth, and let's say that I've set the fence to 5", the first (front) side of the wood will "hit" the blade at 5" from the rip fence but also after 2' or 5' the wood will still "hit" the blade at 5" from the rip fence so actually a "Long fence" can only "contribute" to one thing only....Kickback...

Again, it's only my opinion and I can be wrong....

Regards
niki
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Niki,

Yes, I think what you are saying is absolutely right. It is logical. I was only wondering about how close you get with your method---when checked on a dial micrometer---so that I could evaluate other folks' claims that they are coming within a thousandth or so.

Clearly the cut accuracy is a function of the alignment of the miter gauge and the blade, and if the blade isn't at ninety degrees to the miter gauge it will only "widen" the kerf---as you say.

By the way, do you have a good method for insuring that the miter gauge is at 90 degrees relative to the slot? I have seen your writeups in the past that use wooden triangles. I will have to look them up, but thought you might have a "quicker and dirtier" method.

Best,

Art

Hi Art

I just posted it yesterday on the UK forum as a reply to the same question so, I just "copy & past" it...


Hi Pete
I wanted to step in earlier but, with my English and without pictures, you would end-up at the router table... :)

First, yes - the miter gauge fence must be at 90° to the miter slot (or miter bar), to get a 90° cut.
I think that the picture will show it very clearly (exaggerated of course).

http://i158.photobucket.com/albums/t...j/Dsc00002.jpg


Loosen the nuts on the miter gauge (MG) but not too loose, leave some "friction" so it will not move too easy.

http://i158.photobucket.com/albums/t...e%20adj/01.jpg

Take a good try-square and attach it to the MG fence

http://i158.photobucket.com/albums/t...e%20adj/02.jpg


Push the MG bar till the try-angle "clicks" iron-to iron.

http://i158.photobucket.com/albums/t...e%20adj/03.jpg


You can check it also from the other side

http://i158.photobucket.com/albums/t...e%20adj/04.jpg


And while holding it, tight the nuts

http://i158.photobucket.com/albums/t...e%20adj/05.jpg


Put the MG in the slot and take one long plastic triangle (I found them very accurate and they don't have "moods" because of temp. changes)

http://i158.photobucket.com/albums/t...e%20adj/06.jpg

niki

For better clarity (contrast) I'll show it with my "copy & past" triangle.
Hold the triangle attached to the MG fence

http://i158.photobucket.com/albums/t...e%20adj/08.jpg


Move it slowly while putting your finger in the slot and "filling" that the triangle is in-line with the slot edge

http://i158.photobucket.com/albums/t...e%20adj/09.jpg


Now move your finger to the far end...

What the eye cannot see - the finger can feel...... :)

http://i158.photobucket.com/albums/t...e%20adj/10.jpg

But my best method is to use one of those specially made "miter slot bar"...the bar fits more than snugly to the slot (I have to force it in) and I'm using it while adjusting/checking the blade/slot parallelism (a small deviation on 200mm will show much better on 600mm length)

http://i158.photobucket.com/albums/t...e%20adj/11.jpg


Attach the triangle to the fence and believe me, you will see it...just release the nuts, set it and tight back the nuts

http://i158.photobucket.com/albums/t...e%20adj/14.jpg


http://i158.photobucket.com/albums/t...e%20adj/13.jpg

Regards

Thanks for the great info and tutorial.

and all your other informative posts !!!

mazel tov

Thanks a lot, Niki.

Just what I needed.

Art

Thank you so much Mark and Art

It's my pleasure...

Actually, if you'll look at my miter gauge, you'll see that the wooden fence is connected with two simple screws.
The reason is.....I don't use my miter gauge at all...

I have two "half sleds" and for the "big guys", I'm using the sliding table.

Regards
niki
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