Something Perfectly Square

suggest the mind readers Forum

Bill Tindall, E.Tn.

You have not provided enough information to be able to help you succeed. You have not tried everything because some approaches and equipment will be successful. So if you hope for us to spend time helping you to succeed, you need to spend the time to tell us more about what you are wanting to do and what you have to do it with and what has not worked, maybe because it is being done incorrectly.

how do you know it’s not square?

Bruce, a MN Galoot

Is your square actually square?

Re: how do you know it’s not square?

Ro Gricher

Yes my square is perfectly square table saw is square to the blade from the fence, ruined 2 sheets of plywood very frustrating have 2 sheets left surely figure it out.

Re: how do you know it’s not square?

Yonak

Ron, I think you're going to have to explain your process more. It's impossible to cut plywood square using only the table saw surface, blade and fence unless the piece you start with is square already. What are you using to get square corners ?

Re: Something Perfectly Square

ebd

One thing I would not do is try to cut a sheet of plywood on a table saw. Personally, I would mark it, check square by measuring diagonals, and then cut using a fence attached to the plywood and a good quality circular saw.

some sage advice

Bill Tindall, E.Tn.

We all have been to the place you are at.

Take a deep breath, walk around in the woods for an hour, become calm......then take the time to describe exactly what want to do, what you have to do it with and what you tried.

table saw blades are parallel to the fence

Dick Coers

not square. There has to be a sled, or miter gage involved to make it square.

Great advice, Bill.

Yonak

I especially like the idea of walking around the woods for an hour.

Re: Something Perfectly Square

John McGaw

How big are these squares you are aiming for? When you say "not square" does that mean that one or more corners aren't 90-degrees or does it mean something else?

If you are trying to split a full sheet of plywood into two equal squares with a single cut then you will obviously not make it because 4X8 sheets often aren't and even if they were you would have the saw kerf eating some of the width even if you managed a perfect feed through the saw. If you are trying for smaller squares then try breaking down the plywood into sizes a bit larger than the target -- the handling will be much easier and easier to feed safely and cleanly.

As others have suggested, if you would tell us exactly what you are trying to achieve and how you have proceeded so far somebody could surely give some usable suggestions -- we've all been there trying to do difficult things in the shop (some of us many times).

Try this

John Pappas

Try this on one of your ruined pieces. Mark an x on one edge. Then try to square that piece up by orienting all cuts to that side. In other words, the side with the x will be against the fence , or against your miter gauge as you make your cuts.

Re: how do you know it’s not square?

Bill Howatt

If your mitre gauge or sled is being used, having some sandpaper glued to the face can ensure the workpiece does not slide slightly during the cut.

Your problem is one of the first things I learned with a tablesaw. Just having the tool does not mean perfection, there is a learned technique involved to get the optimum results.

Bill

Re: Something Perfectly Square

Walter Ahlgrim

I find the factory corners of plywood are generally very square and if my rip fence is set correctly it should not be a problem making it smaller with a rip cuts parallel to the current edges.

If you are starting without a square corner, you will need to make one using the miter slot.

I find the miter gage is useful up to 8 maybe 10 inch wide boards.

Once you get bigger you need a miter sled. I built this one over the last few days it is good for about 20 inches. https://s1278.photobucket.com/user/removethis/media/a20200217_163740_zpscamrw4fw.jpg.html

Once I get over 24 inches I clamp a straight edge guide the plywood use a hand held saw.

Do test your square I have found more than a few that were wrong.

Walta

How are you measuring square?

John in NM

Using a try square of some kind or by measuring diagonals?

Some try squares need adjusting, as Walter mentioned. Some are not adjustable.

Good starting point, as others have mentioned, is to describe what you are trying to achieve and what your set up is like - including how you are determining that you've failed to cut square.

Don't give up on it, this kind of problem has confounded just about everyone who's ever cut wood. We all manage to learn from it though, and it's worth it.

Why square?

Barry Irby

Why does what you are making need to be square, precisely square? What are you making? You mentioned 1/16". What was that? Diagonals off by a 1/16". Off a 1/16" off the leg of the square? How big are the pieces? If they are half sheets of plywood it's different than if they are a foot on a side. If you cut a sheet of plywood in two and the pieces are off by 1/16" on the diagonals, it might be good enough. I have built everything from commercial buildings 544' long, to houses, to jewelry boxes. 1/16" mattered in some places on jewelry boxes but not so much on the others. (When I laid out the 544' building and it came out 3/4" too long, the boss was thrilled, we just "gave" them the extra.) So, you may be being too hard on yourself. Tell us more and let us help.

Re: Something Perfectly Square

Buck Nall

Ron I'm the new kid on the block, OK.

Do you have what's known as a ''carpenter square?''

This design/concept is really old, but has it's place.

FOR ME, trying to ''measure your squares'' would be the day I would dig mine out.

YEAW SURE, SOME sa** IS/WILL COME ON & remind us they are not ALWAYS SQUARE!! WELL even rail road steel rails get abused and have to be replaced. Everything created by man needs care and attention.

I'll stick with my original question, aint got one, git one & while your at the dealer/store check several against/with each other!!!

An example of imperfect squares

jessecloud

I took classes at a woodworking school years ago. One of the required tools was a four inch "pocket sized" square. The school knew that a lot of the students didn't have a lot of $$ and probably might not do woodworking very long, so they bought these squares by the case from Lee Valley, a reputable vendor.

When they came in, a class session was used to test the dozen dozen (144) new squares with a very simple test: Take a piece with a known straight edge, register the square in a random spot and draw a line perpendicular to that edge. Then flip the square and using the same edge of the square you used the first time, draw a second line close to the first. If the two were parallel, they got an OK (though this is not a comprehensive test). If the lines diverged (in only 4 inches!!) they were judged to be faulty.

Out of every batch the school bought, two or three would fail. LV always happily replaced them with good squares, but I was surprised that even the good vendors let a few slip through.

BTW, the instructor did his own testing on those the students faulted, not sure exactly what all he did.

And...

Clifton C

We would check a framing square the same way, then tune it with a prick punch.

Anyone else ever done this?

You're obviously...

Clint Searl

...a victim of the Heisenberg uncertainty principle.

Re: And...

George Koch

That's exactly how I've always fine tuned my framing squares also!

Whaaat?

Clifton C

Had to look that one up, couldn't understand it so it must pertain...

Got to, "mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle, known as complementary variables or canonically conjugate variables..."

And thought, he obviously hadn't heard of Occam's razor...

Re: Whaaat?

John in NM

Maybe the project is a box for Schrodinger's cat

Is

Mark Mandell - Gone Round In New Jersey

and isn't

Re: Is

ebd

Do, or do not - there is no try.

Struggling with square

Bill Tindall, E.Tn.

I never got there with the skimpy miter gage on my Delta saw. A long after-market miter gage improved the situation but even with this tool my drawer ends often are not perfect. A table saw sled finally achieved reliably square.

In the mean time.....I learned to adjust panels to square on the jointer(taper cut technique) and the ends of boards on a shooting board. When square is essential I still may need all these tricks.