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. UNPLUG
THE SAW. 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 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.
For a contractor saw, first use a small c-clamp on the rear trunnion and cradle
to keep the assembly from moving. Then loosen the two rear trunnion bolts and use
a stick to tap the trunnion until the blade and screw lightly touch. 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.