Table Saw Miter Slot Question...

[Derek Arita]

I have a new table saw with miter slots that aren't perfectly even from front to back. The front 3" are about .003" to .004" narrower than the remainder of both slots. I discovered this when making runners for a crosscut sled. Is that enough to make a difference in my crosscut sled's cuts? By the way, the saw is a SS JSPro.
One more question...how do I get Notifications to work?

[Maurice Mcmurry]

.004 is within what I am able to achieve with wood runners and wood sleds. As accurate as possible is a good thing. If you are confident about the measurements of your slots you could lap them for higher accuracy. When my sleds have a tight spot the problem is generally with the sled. There is a good YouTube about laping and high accuracy.

https://youtu.be/cwdoUjynpEk
https://youtu.be/cwdoUjynpEk

[Derek Arita]

I just want to make clear that when I take a caliper to the slots, then I get the readings of .004" narrower at the front of the slots. Is that common? I don't know what material the table is made of, but it's not cast iron.

[Tom M King]

That's over the thickness of a sheet of paper. I would want them better than that, especially since they start with the small end.

[Bill Dufour]

0.001 is enough that the human eye can see the mismatch.
Bill D

[Derek Arita]

So is there a fix for the table slots?

[Derek Arita]

Correction! My measurements were in error due to m poor technique. It turns out the slots are within .001 of each other and I guess I’m feeling that error in my runners.

[Dan Cameron]

I have a new table saw with miter slots that aren't perfectly even from front to back. The front 3" are about .003" to .004" narrower than the remainder of both slots. I discovered this when making runners for a crosscut sled. Is that enough to make a difference in my crosscut sled's cuts? By the way, the saw is a SS JSPro.
One more question...how do I get Notifications to work?

Derek, I assume that your intent is to have two precisely fit runners mounted the same distance apart as your miter slots. This makes about as much sense as wearing two watches or assigning two foremen to a work crew. Think carefully about the geometry and the hardness of the materials involved.

[Bill Dufour]

Calipers are not accurate enough for this job. Sounds like it is good enough fro WWorking.. Rather then buy an expensive internal micrometer or snap gauge I would make a wood runner to fit and see how close it is.
Bill D

[Bruce Page]

Calipers are not accurate enough for this job. Sounds like it is good enough fro WWorking.. Rather then buy an expensive internal micrometer or snap gauge I would make a wood runner to fit and see how close it is.
Bill D

Bill, I have to disagree, I get consistent .001-.002 readings using quality dial calipers, always have.

[Maurice Mcmurry]

So is there a fix for the table slots?

They can be sanded, ground, or scraped. if they bo not have slots at the bottom for T nuts it is difficult (it is difficult either way). A way to measure them is to use a feeler gauge and spacer. Your miter gauge and a piece of paper can reveal tight spots.

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