January 6, 2017
Some power tools will do their best work right out of the box. Don‘t expect that from the new cabinet table saw. Unlike a cordless drill or router, a table saw needs a tune-up on day one.
If you are incredibly lucky, every part and accessory will arrive perfectly aligned. I‘ve heard of such miracles but never witnessed one myself. The trouble is that a misaligned saw is a dangerous saw and you won‘t know until you make a cut. At best it will be rough and accurate, at worst the board will kick back at your or become jammed against the fence or blade mid cut.
A table saw is designed so that the teeth at the front of the blade do all the cutting into the board. For that to happen, the board need to travel in a perfectly straight path through the blade.
So the first step is aligning the table so that the miter slots are parallel with the blade. The rip fence also needs to be set perfectly parallel to the blade.
From there, the tune-up switches from parallel to perpendicular, as you set the blade and fence square to the table. Those 90-degree angles are essential if you want to end up the tight joints and square projects. So before you plug in a new or used machine for the first time, go through the following steps. Once your saw is dialed in, it will stay that way for a very long time.
Align the blade parallel with the miter slots
To align the table (and its miter slots) with the blade, you are going to have to go under the hood, at least a little. Most table saw manufacturers attempt this step at the factor, but even the best machines can get knocked out of line during shipping and used machines are a crapshoot.
How you check this alignment is the same on all saws, bu the way you adjust them differs a bit. To check, take a measurement from the edge of one of the miter slots to the front and back of the blade. If the measurements are the same, the blade and table are aligned. I recommend using a 0-to-1 in. Dial indicator for this step. Get the plunge style. You can find one on Amazon for $20 to $30.
Start by raising the blade as high as it will go to increase the distance between back and front, which will give a more precise measurement. In case the teeth are a little uneven of having some pitch built up on them, rotate the blade and use the same tooth for each measurement. The 2 numbers should be within 0.001 in. Of each other, 0.002 at the most.
If your measurements match on the first try, buy a Powerball ticket. If not, you‘ll need to make an adjustment.
Adjusting cabinet saws – on these saws, contractor / portable trunnion (the assembly that holds the blade) are attached to the cabinet, and the table is attached independently, meaning you can move it and the blade stays put.
Adjusting job-site saws – on smaller sawscontractor/portable/ hybrid saws – the blade assembly is usually attached directly to the tabletop. That mean you‘ll have to go a little farther under the hood. Check your manual, and take a look under the table for the attachement points. Newer saws make the easier to access.
Align the rip fence and check the splitter
The rest of the tune-up is easy. Now that the mitter slots are parallel with the blade, you can simply align the rip fence with one of the slots and know that is suqare to the table , too. Just line up the fence with a miter slot, feel for misaligment using your fingers and adjust the fence.
All saws should have some form of splitter behind the blade, designed to sit in the slot that it cuts, preventing the board from turning sideways and kicking back. If the splitter is not aligned with the slot, the board will pull away from the rip fence or jam against it – both bad situations. On some saws you can simply flex the splitter sideways to align it; on other the will be a way to adjust it at its base. If all else fails, use thin shims or washers at the attachment point to shift it slightly one way or the other.
Two stops make accuracy more convenient
For ripcuts and crosscuts alike, you also need the blade to bet square to the blade. There is a stop on the saw to help you return the blade to a perfect 90 degrees every time. You can use a square to realign the blade after each bevel cut, and test cuts to be really sure, but it‘s nice to have a stop you can rely on.
The mitter gauge that came with your saw also should have a stop on it for the 90 degrees setting. If that stop is wigly of sloppy in any way, replace the miter gauge with an aftermarket model. Before suqaring the fence, add a long sacrificial piece of plywood or MDF to it.
The cabinet table saw is the most important machine in the shop. Invest in a good one, and the invest the time it takes to set it up for success.