# Coating on table saw sled affect crosscut sled alignment



## Smile_n_Nod (Jan 20, 2011)

I have a Ridgid jobsite table saw that has a gray coating on the table and in the miter slots. I built a crosscut sled that was aligned at first, but now has become misaligned because, I think, the miter slots have been reamed out by the runners. I also remember the runners initially having a gray residue on them.

What can be done about this? Are there commercial runners that can reliably be readjusted when they're misaligned, but which also stay firmly in place when the sled is in use?


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## notact (Oct 11, 2021)

When you say misaligned, do mean the slots are now effectively wider because the layer of coating is gone, and now there is some play in the sled?

I have a somewhat similar problem, my Bosch router table has a 0.8" miter slot. I put three layers of UHMW tape inside the slot to shim it down to 0.75". Maybe you could do the same, use some tape to shim either the slot or the rails, and make everything snug again.

I had a dewalt jobsite saw that sounds similar, cast aluminum top painted gray, and my homemade sled wore away the paint in the slots. It did not seem to affect the alignment though.


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## therealSteveN (Oct 29, 2016)

Too many unknows to venture a good guess.

Pics may help, but for sure a better description of what materials are being used, and how it was assembled.

Many possible explanations but I doubt the coating of your table is responsible.

A very good runner that allows for plenty of adjustment are the Microjig ZeroPlay


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## Smile_n_Nod (Jan 20, 2011)

More details about the original post:

My sled is pretty conventional, with a plywood base and purple heart Runners glued and screwed to the underside.
When I built the sled, the runners fit perfectly with no slop and I adjusted the fence using the five-cut method the error was less than .002 inches.

When I started using the sled, sometimes the runners would get a little stuck sometimes and I noticed gray material stuck to the sides of the runners in a couple spots. I smoothed the runners a little bit in those areas so they would not accumulate the gray material, which is coming from the table saw sled, and eventually got the runners to slide freely.

Now, with the change in seasons, when I move the sled side to side I can feel the runners are loose in the miter slots and a simple crosscut is noticeably out of square when I check with a Starrett combination square.


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## northwoodsman (Feb 22, 2008)

Check out those runners that therealSteveN posted. They are the best I have found and I have tried a lot over the years. I have used them several times on table saw sleds including for a Dewalt Jobsite Saw and a SawStop Jobsite Saw, both with coated tables. The Dewalt table had slots that were nearly 1/32" difference between the one on the right and the one on the left from the factory. Easy to dial in, easy to adjust if needed but since you can easily adjust the friction they aren't going to scrape the coating off your table or the slots. They are also relatively low profile so they won't bottom out like some do.


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## therealSteveN (Oct 29, 2016)

> More details about the original post:
> 
> My sled is pretty conventional, with a plywood base and purple heart Runners glued and screwed to the underside.
> When I built the sled, the runners fit perfectly with no slop and I adjusted the fence using the five-cut method the error was less than .002 inches.
> ...


From this I would think your most likely is grain orientation of the Purpleheart. You want it as close to perfect quarter sawn orientation as possible. That 5 cut video of William Ng shows a perfect shot of what you want. William is showing making the rails at the 14:45 time stamp.

If you use wood you have to factor for growth across the grain when it's Summer and high humidity.

If you use plastic and screw into it, you have to factor for the squish you get by doing that.

Metal never moves, but often isn't straight in bar stock, so you have to sand it to size.

That leaves those plastic like guide bars I put the link to. The screws go through a hole meant for them, so no squish, and they are super adjustable.

I think worst case with the saw is it's flaking off some dirt, or maybe a finish, but I seriously doubt it's your problem.


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## Lazyman (Aug 8, 2014)

I agree that wood movement is likely the problem. I will bet that they tighten up again once the humidity rises. You can try adding some moisture and see if that changes anything.


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## rwe2156 (May 7, 2014)

I don't think you can correct it without changing them.

Other options: engineered flooring, UHMW.

Sometimes the best solution is commercially made miter bars.


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## HokieKen (Apr 14, 2015)

Agree with others that wood isn't ideal for runners. I use Incra miter sliders for jigs. They have some adjustability built in to get a precise fit in slots that may have some wear.

Is the table on your saw aluminum? The gray transfer you have may be the anodize layer on the aluminum coming off.


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## NohoGerry (Dec 6, 2021)

I recently built a crosscut sled for my new shop. In the past, I had several of different sizes-had to give them away when I moved my shop equipment to another state.
Here are my experiences with building sleds, and correcting them when they stuck, got misaligned, etc.

1) I build my sleds of baltic birch ply and maple runners. The runners are fastened to the sled using short woodscrews every 3 inches or so. I don't glue the runners to the sled and have never had a problem with the screws coming loose-and it gives you the option of replacing them when they get worn.
2) All my sled bottoms and runners get several coats of paste wax, which makes them slick enough to slide easily and not bind. You might try using paste wax when you build the next sled, and it might solve the problem of picking up the tablesaw coating. 
3) Be careful how much material you remove from a sticky runner-or, you'll end up with the problem of "slop" you now have.
4) If your summers are humid and your winters dry, keep that in mind when you're building and installing the runners-i.e. sleds built in the winter stick in the humid summer, and sleds built in the summer may develop "play" in the winter.
5) I've never worried about grain direction when cutting the runners, and it's never caused me any problems.

Used the 5 cut method to square up the fence with the most recent sled built and I'm sold on it! Continue to use it when you build future sleds.

I'm a firm believer in paste wax for sled bottoms and runners, and while I was tempted to buy the UHMV strips commercially available for the runners, the cost got rid of the temptation-LOL! I also used Incra slides very early in my woodworking, but found they weren't worth the price after maple runners did the job adequately.

Hope this is helpful to you.
Gerry


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## davezedlee (Feb 22, 2016)

> More details about the original post:
> 
> My sled is pretty conventional, with a plywood base and purple heart Runners glued and screwed to the underside.
> When I built the sled, the runners fit perfectly with no slop and I adjusted the fence using the five-cut method the error was less than .002 inches.
> ...


could you not coat the runners with something thin, like wipe-on poly, to fill the slop? might take a coat or two, then wax to even things out


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## therealSteveN (Oct 29, 2016)

Personally I'd say no to Poly on a TS top. I see issues with that.


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