Make a sled that handles both square and miter cuts
I’ve written about how I make a crosscut sled, and about how I make a miter sled. Those are great sleds, but I’m always looking for improvements to my technique, and I have a limited amount of space to store sleds. That’s how I arrived at this sled, which combines both those other two sleds into one.
The reason to have two separate sleds is that you want to have a zero-clearance kerf for the blade. It shows you exactly where the blade cuts (making it easier to align parts for cutting, set up stop blocks, etc.), and also helps to prevent chipout on the underside of the workpiece. Traditional sled design calls for two miter bars, with the kerf down the middle of the sled. If you cut a miter on a sled set up for square cuts, you ruin the square cut kerf.
The way around that problem is to remove one of the miter bars. With just one miter bar on the sled, you can use the sled in both miter slots on the saw. My saw at home is a right tilt saw, so when the miter bar is in the left hand slot, the sled is set for miter cuts. When it’s in the right hand slot, it’s set up for square cuts. The result is one sled with two zero-clearance kerfs. It works great, and I have only one sled to store instead of two.
The photos above show me making one of these sleds for the saw in the Fine Woodworking shop, which is a left tilt saw. So, it’s a mirror image of the one I have at home.
Align the sled with the miter slot. Do this with the blade angled to 45 degrees. Locate the sled so that the blade will cut off a section of the base and fence. That way, when you cut a miter, the waste falls to the saw table and isn't trapped between the blade and sled base. The "fences" at the front and back edge have already been glued on, and are used to keep the sled together after kerfing it for square cuts. Neither one is used as the work fence.
Mark the base. This shows where the miter slot "hits" the sled base.
Attach the miter bar. The square helps to hold it in place as you drive in the screws. It doesn't matter if the bar is perfectly square to the base's edge.
Add a second screw. This one goes at the opposite end. You should add at least one in the middle, too.
Kerf the sled. This cut will remove a small section of the base and fence, leaving a zero clearance indicator for miter cuts. The miter bar rides in the right had slot, because this is a left tilt saw. It should be in the left slot for a right tilt saw. And the sled base would be a mirror image of the one you see here.
Clamp the fence to the sled base. Register a combination square against the miter kerf you just cut. It doesn't need to be perfectly square at this point.
Drive one screw into the fence. Work from the bottom of the sled. This screw becomes a pivot point for the next step. Drive the screw head beneath the base's surface.
Now square up the fence. This is the critical step. The square is against the miter kerf, and the clamp goes at the other end of the fence. (The screw holds it in place at the end by the square.)
The second screw locks in the fence. It's driven into the fence at the end opposite the first screw. Then add at least two more screws, one on each side of where the soon-to-be-cut square cut kerf will be. Put the sled in the miter slot to get a rough idea of where the kerf will be.
Kerf the sled again. This time, it's for square cuts in the middle of the sled. The miter bar is in the slot on the left side of the blade. For right tilt saws, it would be in the right side slot.
Always push in line with the miter bar. This will keep you from torquing the sled in the slot, which would result in a cut that isn't square.
Safe miter cuts. Because the part is raised off the table, and there is no base on the waste side of the cut, the waste falls to the table. That leaves space between the blade and waste--it's not trapped, in other words.