Build a Super-Precise Tablesaw Crosscut Sled
Cross cut sleds are a great accessory for your tablesaw, but it can be a hassle to get the sled’s fence square to the blade. It’s also a pain in the neck to get two miter slot bars aligned properly. I know that I struggled squaring the fence and setting the miter bars until I changed my technique for making a sled. Now it’s very easy to do both. I’ll show you how as I make a sled for cross cutting at 90 degrees.
Attach one miter bar to the sled base. That’s all you need. Just one. And the problem of how to align both bars to the slots is gone. And don’t make it. Buy a steel or aluminum one from a woodworking supply store. That way you don’t have to fuss with trimming a wooden one to fit, and you don’t have to worry about the wood bar expanding and no longer fitting in the miter slot. Also, metal ones are durable. You can use them over and over.
Glue and screw a fence to the front and back of the sled. Neither one is used a fence for the workpiece. They’re just there to hold the two halves of the sled together after you cut the kerf through the base. So, they don’t need to be square to the cut and their faces don’t need to be square to the blade. Of course, you shouldn’t glue them down at 45 degrees to the blade, either. Just get them close to square to the blade. Also, they should be taller than highest you’ll raise the blade.
Cut the kerf. Use the blade that you intend to use with the sled. That way, the kerf is zero-clearance and you won’t get tearout on the bottom of your cuts. Then, use only that blade with the sled. That’s how I do it and my sleds last for years.
Attach a fence square to the kerf. This is the fence that workpieces are registered against. I screw the fence to the base from below. Here’s how to get it square. First, screw down one end of the fence. Next, use a combination square or drafting square to align the fence square to the kerf. Clamp it in place and check to make sure it is still square (clamps can move a workpiece as the pressure is applied). Screw down the fence at the other end. It’s now secured at both ends and square. Put in a few more screws and check to make sure that the fence is square along its entire length. A tip: Make the fence for the workpiece taller than the other two. That way you can use a spring clamp to clamp on stop blocks. The fence here is taller than the other two, but the photo angle makes it look about the same height. (Also, the two piece of wood you see are not runners, they’re just wood I used to raise the sled off the outfeed table. The slide is shorter than the sled base and can’t be seen here.)