Squaring my Incra miter guage - a different way

[Johnny Barr]

I've always used the 5 cut method for sleds but the use of feeler gauges isn't suitable for miter gauges until I stumbled across this video .... https://www.youtube.com/watch?v=sL3K_fPLHc4 and all its associated comments and opinions

I tried it and found this method quick, accurate and simple. Assuming your square is accurate this works brilliantly. So much so that I'll use this method for all future sleds and gauges. After this adjustment I thought I'd double check it using the 5 cut method and the final error was negligible.

Do people use this method?

[Mike Gresham]

I've been using Brian's method for years to square my panel sled fence.

[lowell holmes]

This shows how dumb I am. I squared mine with a square against the teeth on my blade. It is a carbide tooth blade.

OBTW, my cuts are square.

[Eric Keller]

if you have carefully squared the blade to the miter slot, using a square on the blade will be pretty close. Ok, so close enough for a hack like me.

[Johnny Barr]

if you have carefully squared the blade to the miter slot

I think that's why Brian's method is so good. It's squaring your fence against the miter slots not the blade so you don't have to rely on the blade being 100% parallel to the slots and I know very few are. It makes perfect sense to me to align against the slots as that's the way the sled is moving. I've always followed the "less than 5 thou" rule. If my fences and balde/slot parallelism is less than 5 thou then in the real world that's good enough. I've read people saying that parallelism needs to be zero or at the very worst less than 3 thou and yet wood expands and blades can deflect by more than that.

This squaring method gets me to a range of less than 5 thou in a few minutes unlike the 5 cut method and as I said above I don't think the 5 cut method is suitable for an Incra miter gauge

BTW I found another of his videos comparing the 5 cut method to his method. The comments and arguments make very interesting reading particularly his justifications. https://www.youtube.com/watch?v=UC_iF5pZxmI

[Osvaldo Cristo]

Thanks for share... simple and direct to the point. Perhaps it could be a good idea to repeat the test at the opposite direction just to be sure your square is "square"...

[Frederick Skelly]

Thanks Johnny! Alternate techniques are always welcome - never know when something will be handy.
Fred

[Johnny Barr]

Thanks for share... simple and direct to the point. Perhaps it could be a good idea to repeat the test at the opposite direction just to be sure your square is "square"...

That's a very interesting idea, Osvaldo I''ll try that and report back but I'm certain I'm square. As I mentioned above I verified squareness by not only the 5 cut method but the "flip one piece over after a cut" method and checking for daylight using a precision square. I'll bury the 5 cut method but in a shallow grave just in case.

EDIT .... Got the same result going in the opposite direction. Would have been surprised otherwise

[keith micinski]

This will absolutely work but it is counting on multiple things being perfectly square with each other instead of just one. I also have found that how you push a piece of wood through a cut and how you use push something for a measurable test isn't always the same and even when everything is perfectly square you don't always get a square cut. Plus the claim it's cheaper and easier has to be wrong because it's impossible to own a table saw and not own scrap for free and it's the exact same process of making test cuts, except now, I have to set up a second measuring device I may or may not have to run my test cuts.

[Johnny Barr]

This will absolutely work but it is counting on multiple things being perfectly square with each other instead of just one. .

There is only one. Fence and miter slot. If they are bang on square then you'll get square cuts regardless of blade parallelism. Yes I'm assuming, however, you are using a good quality square to check this with a smooth edge. That's the only assumption here. Well you could get pedantic and mention dial indicator quality and straight parallel slots of equal width but if your saw doesn't have the basics then the 5 cut method won't work either. I have now tested all my sleds and gauges this way and verified by methods mentioned above. I have clamped the square so there is no movement and pushed and pulled the sled/miter gauge at differing speeds and when the dial indicator has little or no movement I know the fence is perfectly square to the slots and its the slots that dictate the movement.

I'll do test cuts after that but really there's no need. I am convinced after using this method many times that the 5 cut method is not the only definitive method for fence squareness.

[Alan Schaffter]

That method ensures the miter gauge is perpendicular to the miter slot, the most important alignment. It also will yield a square cut even if the blade isn't parallel to the miter slot. However, a non-parallel blade (skewed blade) will result in a slightly wider kerf than normal- it is considerably much less extreme, but it is the same principle as cutting a cove on a tablesaw- the greater the skew the wider the cove. Also, if the stock is not clamped or held securely, a skewed blade can cause the stock to move sideways.

[Johnny Barr]

That method ensures the miter gauge is perpendicular to the miter slot, the most important alignment.

Also, if the stock is not clamped or held securely, a skewed blade can cause the stock to move sideways.

Yes Alan it is the most important, that's why I advocate you shouldn't use the blade as a reference. Good point about the clamping which you should probably do even if you do have a properly aligned blade. Its a bit hard to do however with an incra miter gauge unless you have some sort of hold down which my sleds have.

One thing the 5 cut method has over the way I'm promoting is that final adjustment with a feeler gauge. Its easier with the use of clamps and pivot points than trying to move a fence 5/10 thou by hand but once that dial indicator has little or no movement you know that you are there.

[Art Mann]

The blade would have to be aligned exactly with the miter slot in order to make an accurate adjustment with a square. A blade doesn't have to be adjusted that close in order to rip or crosscut accurately and many saws are not. Some people purposely misalign the blade slightly to insure the back of the blade doesn't create saw marks on the edge of the work piece. I just don't want to count on a previous adjustment that I have made still being dead on. The approach in the method here does not depend on any previous adjustments having been made exactly.

This shows how dumb I am. I squared mine with a square against the teeth on my blade. It is a carbide tooth blade.

OBTW, my cuts are square.

[Dan Russell]

The method in the video you posted is an exceptional alternative to the cutting methods but like Brian said, make sure your square is legitimately accurate. Don't forget to make sure your blade and fence are also square to the miter slots. I use a table saw dial indicator from Woodpeckers to ensure those are aligned parallel to the miter slot as well. Once I have everything aligned to within 0.002" or so, I'll make a rip cut using the fence and then a crosscut with the miter gauge and verify everything is blissful. If there's a gap, do it again and again until you get it right on. Sometimes if you are adjusting your saw blade, just tightening the screws that hold it in place can shift your blade out of alignment considerably. Same is true with your fence and the miter gauge so keep the screws as snug as possible yet allow very minimal adjustments when finalizing everything. Then hold it tight and tighten your screws gently and make sure there isn't any accidental movement while doing so.

[Matt Day]

That’s a great method, thanks for posting (and bringing back an old thread). I hate the 5 cut method!