TS sled stuck

[Robin Frierson]

So I made a new wide TS sled this summer that had a 30in cutting capacity to trim panels. Worked great, had it dialed in with the 5 cut method. So today I put it on the saw and it wouldnt budge. Runners were bound in the miter slots. We had a huge amount of rain from the remnants of Mathew so I suspect the runners swelled. They are QS hard maple, well seasoned so I was surprise as I never had a sled freeze up like this.

So took the 410 and took a few shavings off the runner's side till it started moving. Still a little tight. I just hope I dont regret shaving those runners when it gets cold and they possibly shrink. I am thinking next sled to use steel runners. Is this a common occurence?

[Frederick Skelly]

Happened to me once too. And, yes, iuhrjt was a bit too loose after the weather changed - could be I planed off a tad too much. So on the next sled, I used 3/4" wide UHMW (?) plastic - the white, slick plastic.

I've seen others use plywood runners but there are pros/cons to that.

[pat warner]

Can definitely occur. Immunity with aluminum runners, unless it gets 500°.

[Dan Cameron]

This is a problem with two-runner sleds. We tend to think of plywood and other wood based products as absolutely stable with humidity changes. They are not. So there is a change in the center to center distance of the runners which adds to the possible swelling or shrinkage of the runners themselves. I advocate the use of a single runner for this reason and in recognition that a single runner sled and a two runner sled have exactly the same number of active guiding surfaces. There is this mistique that a two runner sled has an accuracy advantage, but it simply does not.

[Dick Mahany]

Been there also......I changed the runner pair to the Incra adjustable miter slot runners and never had the problem again.

[Brian Henderson]

The solution is not to use wooden runners. Use UHMW plastic or aluminum, those don't expand or contract with temperature.

[Dave Zellers]

You know, sometimes I wonder if it isn't the plywood top that moved in some of these sticky runner cases. Wood runners need to remain an option for those who need to keep their costs down. Vertical grain is important. An adjustment after construction is common. I had to adjust mine once, but not since. It has been perfect after that one adjustment.

[Andrew Hughes]

That's what my sleds always do.Too tight too loose.I don't bother making nice ones anymore.
A good sled cuts perfect 90s even if it's butt ugly.

Aj

[Jamie Buxton]

Yeah, two runners can cause problems. You're asking the panel to stay stable to a few thousandths over the distance between the two runners -- maybe 12" or so. You don't get this problem if you use just one runner.

[Larry Frank]

I have had the same issue with wooden runners. I have switched to the Incra miter slider. I put it on sleds and when sleds wear out move them to a new sled. It is about $21 and works extremely well.

[Eric Commarato]

So I made a new wide TS sled this summer that had a 30in cutting capacity to trim panels. Worked great, had it dialed in with the 5 cut method. So today I put it on the saw and it wouldnt budge. Runners were bound in the miter slots. We had a huge amount of rain from the remnants of Mathew so I suspect the runners swelled. They are QS hard maple, well seasoned so I was surprise as I never had a sled freeze up like this.

So took the 410 and took a few shavings off the runner's side till it started moving. Still a little tight. I just hope I dont regret shaving those runners when it gets cold and they possibly shrink. I am thinking next sled to use steel runners. Is this a common occurence?

Yep, I just made a copy of William Ng's perfect sled. I used red oak runners, I believe he suggests maple or white oak, but I only had access to red. Make sure the grain of the runner is vertical to the slot. I also am going to wax mine with Johnson's Wax to minimize swelling.

[Bill Adamsen]

Like all the others ... I too have had hard maple runners expand to where they wouldn't slide. Here in the NYC region the summer humidity plays havoc with wood. I have never had to do any more than take a few strokes with 120/150 sanding block to free it up. Then wax the base and runners which makes a huge difference in performance..