Micro Adjustment of Table Saw Fence in increments as small as 0.001 inch. Demonstrated on SawStop T-Glide

[StevenWoodward]

Moving a table saw fence by very small amounts can be hit and miss. With a dial indicator at the right location on the fence, I found it is easy to tap the fence and move it by 0.001 inch at a time.

Locate the probe of dial indicator over the fence rail so that dial indicator does not change when the fence is tightened - see red circle in photo below.

A couple of times I have found this fine adjustment helpful:

1. Cutting UHMW runners to fit nicely in the miter slot for floats
2. Cutting mortise and tenon joints on table saw, to get a good fit.

For all other work I just use the measuring tape built into the fence rail. The table saw cut usually gets run over the jointer anyway.

Video Demonstration:

[Leon]

You do have a SawStop, right?

I have the ICS model and the Fence rule is good enough. Sometimes I use a steel rule when setting the fence with a stacked dado.

When do you, need more accuracy than that?

1. You don't need that kind of accuracy for a runner. And you can sneak up one using a scrap.
2. I have literally build hundreds of kitchen cabinet doors, shaker style, with a slot and stub tennon. I do not use a rule or the fence rule at all for cutting the tenons or slots.

And that is wrong. There is no valid reason to run an edge over the jointer after cutting to width on a TS. If your TS is not cutting accurately or leaving tooth marks on your wood you need to spend some time setting your saw up properly and most of all using a good regular kerf blade. Like a Forrest WWII.

After watching your video, re read what I said again. You are using a dial indicator to make fence adjustments and yet you are not getting the correct result. You are having to make extra passes.

If you must use a dial indicator, measure your slot with a caliper and adjust your fence the correct amount the first time.

[whit3rd]

I've built bookshelves with sliding-dovetail shelf connection, (actually half-dovetail) with that kind of precision (using feeler gages which is why the half-dovetail is employed; the test shelf is puzzle-box tight with 0.017" feeler, so the fence needs to move

0.017").

My jig for making the slots is not adjustable, but shrinks and swells with humidity (I've made a MDF spacer that gets clamped into it during storage, or it might warp as well).

It's also good for fine-tuning dadoes before gluing... don't want to waste good white glue in a gap!

[Leon]

No doubt accuracy with small increments is important. BUT your tolerance of .017" is more than 1/64". My TS fence rule as

1/32" increments, in between those increments is .015"

The OP is going for moving a distance 17 times shorter than your measurement of .017. AND he had to reset the fence multiple times to get the correct setting. The dial indicator basically was doing him no good other that telling him how much he was guessing where to place the rip fence. Why use a dial indicator at all if you do not know where the fence should be to begin with.

I can appreciate him wanting to be accurate but he does not demonstrate that he knows what the fence setting should be to begin with.

1. I use a caliper to measure the thickness of the piece that will fit into the dado.
2. I estimate the dado stack cutters needed to make a dado that width.
3. I make a test cut and measure the result. Normally the result is shy of the needed width.
4. I subtract the needed width from the actual width and shim the difference.
5. Almost always no other adjustment in dado width is needed. Plywood being the exception because it can vary in thickness anywhere you may cut.

[whit3rd]

My tolerance is .001"; the typical final adjustment is determined by setting the jig too wide, making a test cut, then using feelers and readjusting. The slot needs to be completely cleared of sawdust before the tail will fit in. Some linseed oil helps it slip into position.

Measuring a dovetail slot is complex, the feelers simplify it.

[Jack]

Never! Most wood pores range from .002 to .008", so tough to need more accuracy than pore size. These measurements are for machinists, not wood workers...

I believe you use the $1000+ domino for these joints, right? They are good but I bet not within a mile of .001" accuracy:-)

After all these years of me bitching about rules with 1/32 increments in the first foot... For me, most of the time 1/8 is enough, I can guess between that for 1/16th, but can live with 1/16th 99.9% of the time. Anything between 1/16th and 1/32nd is a a "tad" and that's more than enough all the time in WW.

[Leon]

Yeah, I never checked, HA! When you mate pieces and you do not feel the joint, that is close enough. No need to measure. ;~)

The only time I deal with "thousandths" is when I use shims on a dado stack. But that is no where .001". Heck wood moves more than that from morning to afternoon in our humid climate.

32's are decent to use, well they are never decent to use, but I use them when building something with dado's/groves. The, less than what you bought, thickness of plywood can throw things off when the carcass is supposed to be 3/4" thick and your front and back face frames receives these panels. The panels fitting into themselves and into the face frames requires a bit of accuracy. And you don't know if dado/groove placement is right or not until glue up. Throw a center stile and vertical panel into the mix and it really gets your attention.

[krw]

Yeah, I call bullshit too.

The grain is a lot bigger than 1mil. I guess a strand can be cut in

1/10th but it's not going to stay on the board long.

But not a 32nd of a 32nd of an inch.

[whit3rd]

Yabbut... when I probe with feeler gages, I'm not feeling that the drag from 0.017" blade is the same as the drag when inserting the 0.016" blade. I can tell how far to adjust the jig by that measurement, and even if the texture is larger than the tolerance, the feel is definitely different. My jigs for this are wood (plywood, and some straight-grained very well-aged softwood as well) and do NOT make a correct fit a few days after being in good adjustment, because the wood does move. Assembled pieces, though, seem to stay tight, for the half-dozen years I've been using them.

[Leon]

You obliviously do not own a Domino. ;!)

[DJ Delorie]

I got the same arguments when I built my router table with 0.001" precision fence and lift systems. "But wood moves!" Yeah, but it won't move *now* and these dovetails are sensitive to a few thou difference. Plus, both pieces will move the same later.

Same with the TS, which now also has an 0.001" precision fence (finally :). It's not about being exactly one inch, it's about being exactly the right size to fit other pieces. Your finger can detect a 0.001" difference in height at a seam, for example, and if all the parts swell together, that feelable seam will be feelable forever.

[DerbyDad03]

re: "...if all the parts swell together"

Shouldn't that be an uppercase, bold face, larger font size, bright red, italicized "if"?

[DJ Delorie]

Perhaps, if the humidity varies that much across the size of your project ;-)