It’s done, I think. That is, the blad is as true to the miter slot as I think I’ll get it. But there might be a better way. Your applause OR groans of disgust would be appreciated–up to a point.
First I rigged a miter slide with a screwdriver clamped in a way that the tip was very close to the blade–maybe less than a 32nd–certainly nowhere near it hitting the blade as it turned.
Second, unhooked stuff and played with the adjustment for 3 days.
Third, finally figured out I needed a feeler guage. Went back to it with a .006″ guage to a point where the guage rubbed the screwdriver tip with approximately the same resistance 2-1/8 in. in front of the arbor as it did 2-1/8 in. behind the arbor with the feeler guage against the same spot on the blade’s body. Then I tested this about 3-1/2 in front of and the same distance behind the arbor. The resistance of the rub felt about the same within each pair of the locations. I marked the spot on the side of the blade body with a pencil and so tried to hit very close to the same spot within each pair of comparisons. I don’t really have a flat blade so the resistance from pair to pair was justifiably different.
Fourth, trembled in fear if I ever loosened the trunnions again, it would be a week before I got nearly this close again.
It feels good now, but I was sure there would be an easier way.
Thanks.
Replies
Sounds good to me, Burly!! As many regulars on these boards know, I went through a terrible time with my contractor's blade alignment (it appears that the saw was dropped at some point before I got it, good grief!).
Despite all the glories of dial indicators and such, your system sounds great to me. I used a vaguely similar method (it involved my Incra 1000 miter gauge + a projection to the blade), and my test cuts are just fine thank you, so it must have worked.
Doesn't it feel great?!
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Uhhm,.... I like the dial indicator method. Since my saw has a problem. I figurd it out with this tool.
I've since beveled the front end of this tool to ride lower on the blade.
john g
Here is the low tech, low cost way to align a tablesaw that I learned maybe forty years ago and teach to my students now.
Make 3/4 x 3/4 x 12" hardwood stick. Drill a hole somewhat centered in one end and insert a brass #8 x 1" round head wood screw about half way. Raise the blade completely up. Clamp this board in your miter gauge (if you determine that there is some slop in your slot to miter gauge, use a playing card to take up the slop) so the screw head just about touches the blade at the front. Now rotate the blade by hand (BTW, unplug the saw) and determine which tooth is the closest. Adjust the screw in or out until it just touches this tooth. Mark this tooth. Rotate the blade so the tooth is now at the back of the table and move the miter gauge/stick assembly to the back and see if it touches the marked tooth to the same extent. If it doesn't, adjust the trunnion (if a contractor saw) or the tabletop (if a cabinet saw) until it does. The blade does not move directly around the center so you will need to repeatedly go back to the front of the blade, readjust the screw, and then again measure the back. Be sure to check after tightening the trunnion as the trunnion frequently moves when being tightened.
The same adjustment gauge can be used to set the fence parallel to the miter slot. Slide the miter gauge to the front of the table and move the fence over to the screw head and insert a playing card between the screw head and the fence just so you can move the card as it touches both the fence and the screw head. Now move the miter gauge to the back of the table and see if you have the same feel when you insert the card. I like my fence absolutely parallel--if you want to have a slight opening to the fence, you can easily estimate the opening by adding a thickness of paper to the card.
I always show my students with a dial gauge that their adjustments are within .001 - .002.
You can also use the same gauge to measure blade runout by using a $5.00 feeler gauge.
Finally, after you are satisfied with the above adjustments, check the position of the splitter to make sure it is exactly in line with the blade.
Bottom line, there is no need to spend more than the $0.05 for the brass screw.
Thanks, Howie, I read your note 3 times to make sure, and I can say that basically the only difference is that you spent time & wood cutting up a stick and putting on a screw whereas I used a screwdriver with a square handle. Same difference.
Part of my problem was the miter slots on this 50 year old saw have nicks & dings--not exactly true slots I don't think. Another was the trunnions--they have not been move in years and so were a little rough, especially with those heavier guts in those old saws. I swear I don't think my rubber mallet moved them at all. I hated to use a steel hammer but they wouldn't move.
Better, however, you have 40 years experience, and I have one week. I like the feeler guage better than the card because then all the surfaces are metal--the blade, the screw(driver), and the feeler guage. It makes me feel like I'm on the right track.
And Forest Girl, don't you know that's a great feeling!
Thanks for the help, folks.
Hi
Here was my problem, I would raise the blade as you say all the way. Do the stick alignment method, and be sure I was on. Only to lower the blade and burn wood. Turns out, My Contracter saw is defective. I talk to the people at General but, they really wanted to put it on me. Anyway I made this jig and what I found out is as I lower the blade!!!!!!!!!!!!!!! The BACK of the BLADE MOVES INTO THE FENCE!!!! I've since beveled the tool so I can read lower on the blade. And talk about mad. I the U.S. Joniors Tools carried General for about 6 months. Anyway, the deflection is about .05 and I deal with it by raising the blade and compensating. Bacause most cuts are at around 1".
What a pain HUH?
john g
Some miter gauges, like Rockwell, or Delta have holes in the ends of the body, perpindicular to the fence, or slots, and have thumb screws. These holes were used for a variety of cut off devices over the years. But what I found was that a Bic ball point pen, or a round pencil, fit perfectly into the hole. This allows a very small point to be used when checking for run out or square.
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