Build
A flat MDF base, two hardwood runners fitted to your mitre slots without slop, and a fence at the back. Screw the fence at one end only for now.
The five-cut method
Take a square-ish offcut. Cut one edge, rotate 90°, cut again, four times. On the fifth pass, cut a thin strip off the first edge. Measure that strip at both ends: any taper is four times the fence error, which is what makes the method sensitive.
Divide by four, adjust the free end of the fence by that amount, and repeat. Two iterations normally gets it under a tenth of a millimeter over 300 mm (11.8 in).
Then fix it
Screw the second end, add a blade guard block at the back, and mark the kerf on the fence so you can align a cut line without measuring.
This does not replace your machine’s manual. Guards, riving knives and safe working procedures differ between machines, and the manufacturer’s instructions for yours take precedence over anything written here.
What comes up most often
Why build rather than buy?
Because a sled is tuned to your saw, and the tuning is what makes it accurate. A bought jig has to fit many saws, and generality costs precision here.
Last reviewed 2026-08-12
