Matted":22cc07jo said:
Sorry, really silly question - can anyone tell me what width the Mitre Slot are on the table. I was going to by some runners to make a cross cut sledge, and I want to make doubly sure I get the correct size.
You're better off makign your own and following the technique of putting the slightly narrower runners in the slots (with washer underneath so they are proud of the machined top) and put playing cards in the INSIDE EDGE (closest to the blade) of both of them so the runners outside edge is pressing against the slot.
This way you get very little slop and you can just run a bead of glue on the runners and place the sled on top - once dry pull it out and it's done.
If you want to get REALLY fancy you can add expanding slots to the runners, in the same manner as fingerboards get locked into a mitre slot with a runner, so that you can deal with any wear over time. Just make sure not to run any glue on that part of the runner so it's free to expand with the embedded screw.
DO NOT lock down to final position the rear fence for the sled until you've done everything else - run the sled through the saw to get the blade slot and ONLY THEN set the rear support fence at 90deg.
A smart man will set the fence only at ONE end with a screw, clamping the other end down firmly and make several passes with the sled using a wide section of ply offcut or mdf using a factory machined edge on the rear fence support - the wider (front to back) the better, as the longer the 2 sides of the cut section are, the more accurately you can dial in the rear support to 90, and you do that by making the cut, then turning the section face over face and seeing if it lines up perfectly, rather than using a square. Keep incrementally tweaking until the support fence and the blade slot are at 90 - mark up the free end where that is on the sled, just in case, then screw it down without moving the clamp (like I did and had to start over).
Sorry if you knew all that - if you didn't Hth.
There are umpteen ways to make a sled and you might want to look at various designs that have T-track embedded in the base for holddowns to keep your fingers out the way, and T-track along the fence for stop blocks, moveable sacrificial fences in front of the main rear fence support, a section of persex front to back over the blade slot to stop debris and add a bit of safety and an added sacrificial block the the rear of the fence to keep the blade embedded and add strength to that section of the fence.
Might as well only make it right once, right?