In article ,
"Chuck Hoffman" wrote:

Just finished making a new crosscut sled. Cut a piece of 3/8" X 3/4" oak
for the miter slot runner, carpet-taped it to the back of the 1/2" ply sled
bottom and attached it in place with screws. Cut a piece if hard maple for
the fence, screwed down one end and squared it up with my accurate framing
square. Clamped it in place and installed another screw to secure the other
end then put a third screw in the middle. Trimmed off the edge of the sled
and test cut some wide plywood panels. They came out perfect. Flipped them
over to check and they were still perfect.

First time I've EVER gotten it right on the first try.

A good thing when making a sled is to plane a small bevel into the
forward lower edge of the fence before attaching it. You end up with
something that looks like this:

| |
| Fence |
| |
| |
| |
| |
+------/
+------------------------------------------
| Plywood base
+------------------------------------------

The little relief space makes it easier to get a piece of wood flat up
against the fence without tiny imperfections in the corner (or bits of
sawdust) from holding it off the fence face. It's the same reason
squares often have a little cutout at the inside corner.