Clean, burn-free cuts on your table saw depend, to a large extent, on parallelism between the saw blade, miter slots and rip fence. The DigiAlign from iGaging, which sells for around $70 as of 2011, can help you dial in all three of these important saw parameters, plus more. It features a pair of interlocking aluminum crossbars that bolt together to form a T-base. The shorter bar has tiny springloaded bearings to create a tight fight in the saw’s miter slot. The longer top bar is slotted and forms an extendable mount for a digital dial indicator (included) that is accurate to .001".
Once assembled, you can first use DigiAlign to measure the runout of your saw’s arbor shaft and flange, then check the blade for flatness. Slide the gauge along the miter slot to determine parallelism between the miter slots and blade. Once those settings are tuned up, use the DigiAlign to square up your rip fence by taking readings at both of its ends. No more cobbled shop jigs needed to achieve a perfect tune-up.
If that’s not enough, you can also change the configuration of the two base bars and convert this jig to take vertical measurements. That option makes it suitable for setting jointer knives or adjusting infeed table depth.