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Table Saw Test 2
Checking Arbor Flange and Saw Blade Runout
If you have ever watched a saw blade "wobble" to a
stop, and wondered what was causing the problem, this test is for you! When I
was designing the A-LINE-ITÔ , I wanted to give you
the best diagnostic tool in the industry. The following technique is one that we
developed to do that no other alignment system in the country can; check your
arbor flange and saw blades for runout. This technique, soon to be awarded a
patent, is made possible by the Spring and Nut assembly provided with each
A-LINE-ITÔ System. Assemble the A-LINE-ITÔ
as shown in the photo, and position it into the miter groove of the saw. I would
recommend that if the threads of your arbor point toward the right, (you have a
left-tilt saw) I would position the A-LINE-ITÔ in
the left groove, as shown in the photo above. If the threads point toward the
left, (you have a right-tilt saw) I would position the A-LINE-ITÔ
in the right groove of the saw. By doing these tests in this manner, you should
have room to get your hand near the arbor without interfering with the dial
indicator.
The following steps should be taken to assemble the A-LINE-ITÔ to test runout in arbor flanges and saw blades.
Insert the spring into the knob, and "back out" the nylon locking screws to clear the center hole in the nut.
Place a blade on the arbor, and install the blade washer. Do not install the factory supplied arbor nut.
Place the spring/nut assembly onto the arbor shaft, and press the nut toward the saw blade to fully compress the spring. Tighten the nylon locking screws to hold the spring and nut on the arbor shaft of the saw. When done properly, the spring keeps the saw blade firmly biased against the arbor flange.
Elevate the arbor to its highest point, and then lower it about ¼".
Assemble the A-LINE-ITÔ as shown in the photo, and position it into the guide slot of the saw. Position the tip of the dial indicator as close as possible (without making contact) to the top of the table saw.
Zero the dial indicator. To check to insure the blade is firmly biased against the flange, push the blade away from the flange, and then release it. If the dial indicator consistently returns to zero, the spring and nut are properly installed. If the reading "drifts" when the blade is released, more tension should be placed on the spring.
The following procedure allows you to test the runout produced by the arbor flange.
Place a small scrap of wood (I’d use something 1/8" thick by ¾" wide by 6"-8" long) directly in front of the blade (with long dimension parallel to the blade).
Slide the piece toward the blade. Center (and hold) the ¾" in the gullet between two of the blade teeth.
Position the A-LINE-ITÔ so the tip of the indicator is as close as possible to one of the tips on the saw blade.
Grasp the spring/nut assembly, and rotate the arbor shaft in the normal direction of blade rotation. (The tooth on the blade should catch on the wood scrap, stopping blade rotation.)
With the blade held in this position, slowly rotate the arbor of the saw. The dial indicator will show you the amount of runout produced near the tips of the blade.
Though I have never seen "factory specs" on this subject, I would begin to be concerned if this reading exceeded .004" - .005". (Four to five thousandths of an inch)
The following procedure allows you to test the runout in your saw blades.
Slide the A-LINE-ITÔ to a position that places the tip of the dial indicator just inside the gullets (notches between the teeth) of the saw blade. (It should be at a position that will allow you to rotate the saw blade without the indicator tip getting stuck in one of these gullets as you rotate the blade).
Grasp the spring/nut assembly, and hold it with one hand.
Use your other hand to slowly rotate the saw blade. (Be sure to take your hand off the blade frequently to insure that you are getting accurate readings as you rotate the blade.)
A high quality blade should be expected to run with no more than .003" (three thousandths of an inch) runout as it is rotated through a 360 degree test, while some low-to-mid quality blades may run in excess of .010". I highly recommend the use of a top quality blade if you expect top quality cuts from your table saw.
NOTE: By marking a "low" spot on the arbor and a "high" spot on the saw blade (or vice versa) you can minimize the total amount of runout produced by placing the two marks together. This also gives a consistent kerf width, as long as you always place the two marks together every time you install the saw blade.