Crosscut sled runner problem

[Greg Urwiller]

I'm building a crosscut sled for my tablesaw. I got 2 Kreg aluminum runners to use for the sled. I've seen a lot of tutorials for building these, and several show to shim the runners in the TS slots to keep sideways movement to a minumum. So, I put tape on the outside of the slots, just enough so the runners weren't tight, but so they would still slide easily but keeping any sideways movement to a minimum. Put a little superglue on the runners, laid the sled down on them for a short time to set, then removed the sled and screwed down the runners. Now my problem! The sled will slide about halfway across the table then binds up. I don't have my 12" dial caliper anymore to measure, but apparently the TS slots aren't perfectly parallel. Looks like the runners are too tight to the inside of the slots. So, can I sand the aluminum like you would wood/phenolic runners, or will this just gall the aluminum? Or, is it just going to be easier to break loose one runner, and hope I don't tear up the plywood too much, fill the holes, and just move it slightly? The Kreg runners do have several threaded crossholes for plastic set screws to take up any movement, but I hadn't figured on needing these. By the way, will heat do any good on the superglue or am I pretty well screwed on this? Thanks. Greg

[Prashun Patel]

I would first verify that the slots are parallel to each other. It is probably the case that you just didn't glue the runners perfectly parallel, though. DAMHIKT. You can test the parallelness using your miter gauge or a shopmade runner, with a block and a screw attached to it. Just touch it at the front and back of the blade. Honestly, I eye-ball my alignment with a similar gauge and it's been good enough; at least good enough to prevent binding...!

Another good trick for aligning yr runners can be found in this month's issue of FWW: basically, you split the deck into 2 pieces at the blade kerf. Then you attach each runner to each half, gently clamp the 2 halves together so the runners are riding snug to the inside surface of the respective slot. Then you attach the front fence, and finally the rear fence, taking care to square it. Last re-rip the kerf. I have not tried it, but it does seem foolproof...

[Greg Urwiller]

Looks like the slots are about .015" farther apart at the rear of the table compared to the front. So, I didn't get the runners parallel on the sled. But, there's no way to keep the runners both, snug to the inside of the slots (like I had them), and parallel at the same time. It looks like I'll have to make them parallel from the widest point of the slots. Hopefully this won't be to sloppy at the narrow end so I can get a square cut. Greg

[Prashun Patel]

A sled should run with zero slop and no binding. Is one of the runners parallel to the blade? You can always make a single runner sled...

[Kyle Iwamoto]

A sled should run with zero slop and no binding. Is one of the runners parallel to the blade? You can always make a single runner sled...

There's your answer! I was going to mention that. But then, I keep making 89 degree sleds. Making the sled, making sure the slots are parallel, 90 degree front and back fences. Ripping the slot last does NOT guarantee a 90 degree sled. DAMHIKT. Make the fences adjustable. Do NOT glue them in until after you make your test cuts. My beautiful koa fence sled will forever be wall art.

[Mike Manders]

if I were you I'd pop the runners off the plywood and start fresh. Put a couple of nickels in the miter slots so that the top of the runners are proud of the table surface. Then add some double sided tape and set the sled down into place (I reference off the fence to make sure it's square). Make sure it rides smoothly then screw the runners down, and if you have any slack use the set screws to take it up.

[Joseph Tarantino]

Looks like the slots are about .015" farther apart at the rear of the table compared to the front. So, I didn't get the runners parallel on the sled. But, there's no way to keep the runners both, snug to the inside of the slots (like I had them), and parallel at the same time. It looks like I'll have to make them parallel from the widest point of the slots. Hopefully this won't be to sloppy at the narrow end so I can get a square cut. Greg

start over and follow the method shown in this thread by niki:

http://www.ridgidforum.com/forum/t13945/

i built 3 CC sleds using his technique and they've been dead on accurate from day one.

[Greg Urwiller]

Thanks everyone. I got it done last week. Had to pop off one of the runners, shimmed it out from the inside edge of the miter groove the thickness of 1 pc of painters tape and reattached it. I then took up any sideways looseness with the plastic set screws that came with the runners. I hadn't intended on having to use the set screws to adjust the fit, but hey, that's why they were included right? Anyway, it's all squared up and running.

[glenn bradley]

Thanks everyone. I got it done last week. Had to pop off one of the runners, shimmed it out from the inside edge of the miter groove the thickness of 1 pc of painters tape and reattached it. I then took up any sideways looseness with the plastic set screws that came with the runners. I hadn't intended on having to use the set screws to adjust the fit, but hey, that's why they were included right? Anyway, it's all squared up and running.

Excellent. You will love having a sled and wonder how you got along without one.