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Adjusting Fence Parallel with Miter Slots

3908 Views 15 Replies 10 Participants Last post by  DesertRatTom
Setting up the new table saw. Adjusting the fence for parallel to the table/miter slots. Instructions are clear enough on HOW to do it (loosen this screw and then adjust with that screw), but are silent on just how close to parallel the fence should be.

Out of the box, it was slightly closer on the outfeed side. I've adjusted it to where it is about 0.010" further away on the outfeed side. My rationale is that it should be either perfectly parallel or slightly wider on the outfeed side to lessen the tendancy to bind.

My method is to secure precision parallels against the miter slot on the near and far side of the table, by expanding adjustable parallels in the slot between the precision parallel and the opposite side of the slot. The precision parallels do not move at all. Then use feeler gauges to measure how far away the fence is from each parallel. This is a jobsite model table saw, so its fence is not nearly as secure as on larger saws, so there is some give and take when it comes to consistency of clamping/position. Taking that into consideration, I loosen and re-tightened the fence several times, resulting in slightly different positions each time and consequently, different thicknesses of feeler gauges come in to play, but the difference is consistently about 0.010" between the two positions.

Is this a suitable method and what differential should there be, if any?

Thanks,

Rick

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Did you check if the blade is parallel to the slot? It's important to check that first.
If the blade is parallel, then I'd try to get the fence a little closer at the back end, maybe .005"?
You want to make sure the back of the blade doesn't rub against the wood after it's cut.
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Did you check if the blade is parallel to the slot? It's important to check that first.
If the blade is parallel, then I'd try to get the fence a little closer at the back end, maybe .005"?
You want to make sure the back of the blade doesn't rub against the wood after it's cut.
Yes, the blade is parallel. Checked that first following the instructions, which were to set an adjustable square to just touch a tooth on the front, mark that tooth, rotate the blade to where that tooth is at the rear and check again with the square. The tooth just scrapes at both locations.

Rick
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I agree with Gerry. Try to set the fence as parallel as your patience will allow. If it has .005" clearance at the outfeed end, call it good...for safety, you don't want it at an angle that pinches your wood on the outfeed end, resulting in kick back. I like your setup. Occasionally re-check your fence, to be sure it stays that way.
You don't really want the back of the blade scraping either side of the cut but the worst scenario is having it too close on the fence side as that both traps it and binds and increases chances of a kickback.
Your idea should work, but personally I’d buy a cheap dial gauge . I think my run out was around .01-.008 also . Tried less but found it was binding with harder woods
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Your idea should work, but personally I’d buy a cheap dial gauge . I think my run out was around .01-.008 also . Tried less but found it was binding with harder woods
Not sure which idea you are referring too. But, I do have indicators and I was working on this setup when I took the time to look here. This is a test dial indicator on a Noga magnetic base, sliding on a 3/4" precision parallel in the miter slot. During a traverse, I am holding it firmly against the close side and the bottom of the slot.


I am a little troubled with the readings I've been getting, on both sides of the fence (without moving/releasing the fence). I want to work things out a bit more before reporting on anything.

Rick

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I'm not sure that a gauge is as good as just looking at the cut it just made as when you push a board in there are possibilities of things flexing and bearing free play removed which the gauge won't show you. If the fence is on the right side and you have heel marks from the blade on that side then the fence needs adjusting away from the blade. If the heel marks are on the off side then fence needs adjusting inward. If you have intermittent heel marks on both sides then you might need to use blade stabilizers.
I keep mine at about 4 one thousandths out at the far end. I have a different T type fence, but I've found I need to keep the track it ruins in clean. Sawdust buildup will push the alignment off slightly. Sounds like you're doing the best you can and it seems to be right. A couple of years ago we had a string on here about precision, with finally petered out with Hey, it's wood, not metal. It moves with humidity, with internal stresses, with inflexible glued joints. You can only be so precise in your cutting. The other side of that discussion was that why NOT go for the maximum precision possible.

The proof is in the cutting.

Some of this has been covered, I just forgot to post when I wrote it.
I keep mine at about 4 one thousandths out at the far end. I have a different T type fence, but I've found I need to keep the track it ruins in clean. Sawdust buildup will push the alignment off slightly. Sounds like you're doing the best you can and it seems to be right. A couple of years ago we had a string on here about precision, with finally petered out with Hey, it's wood, not metal. It moves with humidity, with internal stresses, with inflexible glued joints. You can only be so precise in your cutting. The other side of that discussion was that why NOT go for the maximum precision possible.

The proof is in the cutting.

Some of this has been covered, I just forgot to post when I wrote it.
Yes, I agree, there is only so much that we can do in the way of precision since it is wood. I think I've done about as much as can be done with this fence. I also think, that while I really like the saw, the fence is the weakest part of it that I've found so far. I've cut several pieces of 1/2" Baltic birch plywood for the crosscut sled and all seems to be working right. Not seeing any blade drag marks, cuts are very clean, straight and uniform, so I'm just going to work with it. Got projects stacking up waiting for this sled, so I just need to get on with it.

Rick
For no particular reason, I popped for the Woodpecker dial caliper in the picture. About $100, but I find it's so easy to use that I use it more often. It showed me there was about .004 variation in the face of the fence. Not much of an error, but I needed to take it into account setting the outfeed end.

I bought a Laguna Fusion 10 inch saw, found one of the wings was warped just about one mm, so I couldn't get the table really flat. Called Laguna (about 2 hours away in Newport Beach area and they said bring it in. So I did and they replaced the entire saw with a new one they'd set up perfectly! They even used a huge machined straight edge and feeler gauges. The top had one small area off to the right, near the end that was .015 low, which is basically perfectly flat. In case anyone wonders why I LOVE Laguna tools. Here's the picture, pretty, isn't it. Definitely an indulgence though.

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@DesertRatTom. She's a real beauty Tom!
I used a dial caliper and a MAG-DRO Mitre Slot Caliper Base (available from Amazon). You do not need an expensive dial caliper biter slot tool. This one is plastic with tabs to hot it tight to miter slot. I set the blade and miter slot about .00015 to .0002. You will need to mark the blade tooth when the in-feed is measured and then blade is rotated for the second reading. You should not use the blade using different reference points. Always the same spot. . You the set the fence parallel to miter slot. I set mine +.0004 ( the thickness of a piece of blue masking tape). If the fence is to wide on out feed the cut will not be parreel, to tight and you will hear the saw blade zing as the piece clears. It will take a little time to set it up, but the cuts are worth it.
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I prefer to set my fence parallel to the blade. Using a riving knife and safe cutting practices reduces the chance of kick back. I use a master plate similar to thishttps://www.grizzly.com/products/Grizzly-Master-Plate/G7582 it eliminates any variation there may be between different blades. I use the plate to set up my miter saw as well.
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I'm going to post just to pull this up. It's a nice little thread for anyone setting up their table saw. BTW, my fence is the one that comes with the Laguna saw, and it is VERY precise.
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