When you take delivery of your brand-new bench saw, there is an important check that you need to make before you even think about sawing. It's a check on the squareness of the table top compared to the blade. If you don't carry out this check, you could be in for some big trouble. Incidentally, this is an important check to carry out whether your bench saw is a Ryobi, Makita, Dewalt DW745 or whatever.
Slot-to-blade
You need to take a measurement now. Before you can do this, you need a finely-graded ruler, say one that's graded to 1/64th of an inch or the metric equivalent, so that you can get a really accurate measurement. At one end of the blade slot, with the saw unplugged, pick a blade tooth and measure from the tip of that tooth to the edge of the slot, at 90 degrees to the edge of the slot. Next, rotate the bench saw blade so that the same tooth is at the other end of the blade slot. Now, take the same measurement from the tip of the tooth to the edge of the slot. By the way, if your measurement falls between 1/64th markings on the ruler, just interpolate as best you can.
Loosen Those Bolts
Take a look at the bench saw manual now, because you need to know how to loosen the bolts that hold the table top in position. Usually, there will be four bolts, one on each corner, but they all vary a little so check out the manual. Next, loosen all but one of the bolts. As for the final bolt, loosen it a little, but leave it tighter than the others. The idea is that you will be able to swivel the table top a small distance but the final bolt will be tight enough to stop the top sliding around while you check the measurements again.
The Dowel Test
Now, get a piece of dowel and tape it really securely to your mitre gauge, so that the dowel is in a place where the blade will cut it at right angles. With the mitre gauge in the mitre track, make a cut through the dowel and then switch off the machine. Next, adjust the mitre gauge and align the end of the dowel at one end of the blade slot so that a tip of single tooth on the bench saw blade is agaisnt the dowel. Just bring the end of the dowel to the blade until the tooth "squeaks" on the end of the dowel. Tighten the mitre saw gauge in this position. Next, rotate the blade so that the same tooth is at the other end of the slot, and see if the end of the dowel squeaks up against that tooth in exactly the same way as it did at the other end of the slot. If it does, you have a blade that's parallel to the table top slot and all is well.
Tap and Re-Test
If the test fails, because the blade tooth is against the dowel to a different extent at one end of the slot to the other, you will need to "tap" the table top so it rotates a little in the appropriate direction and then carry out the dowel "squeak" test above. Remember to rotate the blade and measure against the same tooth at each end of the slot. You may need to repeat this a few times to get it right. Once you have got everything just right, carefully re-tighten all the bolts without moving the table top, test a final time, and then rejoice in the knowledge that your bench saw table is correctly aligned!
There's more great bench saw information, aimed at UK enthusiasts, right here: Bench Saw UK
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