Squaring

[suds]

I realize this has been brought up in various ways and I've read quite a few about parallel and right ange etc.  This may be a dumb question so please excuse a novice lack of experience.  But, if the diagonal measurement was the same wouldn't it always be square?  I have been using this technique and it seems to work so far. ???

 

[WarnerConstCo.]

You mean like 3,4,5?

 

[score0matic]

he said digital 
so 1.5, 2,2.5  hehehe

 

[chrisrosenb]

I realize this has been brought up in various ways and I've read quite a few about parallel and right ange etc.  This may be a dumb question so please excuse a novice lack of experience.  But, if the diagonal measurement was the same wouldn't it always be square?  I have been using this technique and it seems to work so far. ???

It will always be square as long as the parallel sides are the same length.

 

[suds]

I use the A squared + B squared = the square rood of the paralell squared.  Since I'm not a experienced woodworker I'm wondering if I'm missing something here ... if not, why wouldn't you always use that formula to make sure your woodwork/panel always came out square?

 

[alanz]

Chris,

"It will always be square as long as the parallel sides are the same length."

In any parallelogram, the pararallel sides are the same length, but that doesn't mean anything is square (that right angles are present).

Diagonals being equal doesn't mean it's square (could be any angle, depending on the lengths of the sides, they don't even have to be parallel.)

If the parallel sides are the same length, AND the diagonals are the same length, then it should be rectangular (right angles are present).

Sound reasonable?

 

[Chas]

It will come out as square as you can measure it. I am sure it would be easy to measure something to say 1/64th of an inch and then put a big woodpecker square on it and see a gap. It depends on how square you need it. I built a small cabinate bookshelf and very little of it was exactly square yet it turned out perfectly serviceable. I wouldn;t want to cut a bunch of big side panels for cabinates having set up the MFT by measuring with my eyes anyhow.

 

[chrisrosenb]

Chris,

"It will always be square as long as the parallel sides are the same length."

In any parallelogram, the pararallel sides are the same length, but that doesn't mean anything is square (that right angles are present).

Diagonals being equal doesn't mean it's square (could be any angle, depending on the lengths of the sides, they don't even have to be parallel.)

If the parallel sides are the same length, AND the diagonals are the same length, then it should be rectangular (right angles are present).

Sound reasonable?

I am sorry that I did not explain well. I am a woodworker & not a writer. I should have used parallel  parts instead of sides.

Sound reasonable?

 

[suds]

So...for us novice guys...IF I measure both sides and they're equal...AND I measure the diagonals and they're equal (or the square of A2+B2)....it should be a square.
So, I'm wondering why all the difficulty,for some who post here, to create a square panel?  I'm wondering if I'm missing something or a situation where that wouldn't be true?  I realize this is really pretty elementary for most of you but I've botched up too many little projects, until I found this forum and Festools.

 

[jonny round boy]

So...for us novice guys...IF I measure both sides and they're equal...AND I measure the diagonals and they're equal (or the square of A2+B2)....it should be a square.
So, I'm wondering why all the difficulty,for some who post here, to create a square panel?  I'm wondering if I'm missing something or a situation where that wouldn't be true?  I realize this is really pretty elementary for most of you but I've botched up too many little projects, until I found this forum and Festools.

If both sides are equal, then you can measure the diagonals to check that the panel is square, once it's been cut. That's fine, but if it isn't then it's too late.

Whilst you can also use this method to mark it square before you cut it, it's very impractical to do so.

I think that's the issue most people have - cutting square in the first place, not checking square afterwards.

 

[JohnDistai]

I'm glad you brought up the question.  I don't know how to make a square panel.  I'm going to play around with my MFT and TS to see what I can come up with, but I don't know exactly how to do it.  I can remodel my house, and do some very nice tile work, but when it comes to making a cabinet or something, I can't do it at this point.  So I'm glad you brought up the question.

 

[Corwin]

If both sides are equal, then you can measure the diagonals to check that the panel is square, once it's been cut. That's fine, but if it isn't then it's too late.

Whilst you can also use this method to mark it square before you cut it, it's very impractical to do so.

I think that's the issue most people have - cutting square in the first place, not checking square afterwards.

Good one, Jonny!      [wink]

I've seen this, 'just use math' response here before and always wondered how well that was working out...  One has to be extreemly fast in measuring, marking and aligning to those marks to beat the ease, speed and accuracy that one gets when using a speed square.  Heck, maybe that's how they got the name.  [scratch chin]

[popcorn]

 

[suds]

Corwin,
I was thinking about a speed square or square, but from what I've read here many squares aren't that square and a small fraction of error turns into a big deal when making cabinets. 
It would seem to me that if one corner was square and you knew your A and B dimensions, you'd run the math and make your marks...?

 

[AlexThePalex]

But, if the diagonal measurement was the same wouldn't it always be square?

Nope, that's not enough. Take for instance a perfect trapezium/trapezoid.

[attachimg=1]

Both diagonals can be exactly the same length but still you have no square.

So...for us novice guys...IF I measure both sides and they're equal...AND I measure the diagonals and they're equal (or the square of A2+B2)....it should be a square.

That's a better way to check for squareness. Both pairs of opposing sides have to be of exactly the same length and the diagonals as well. Only then will you have a perfect square.

So, I'm wondering why all the difficulty,for some who post here, to create a square panel? 

Creating a perfect square is difficult because it is easier to cut not square. Simple as that. Now, the way you talk about measuring for squareness is pretty useless in my humble opinion because you can only do it after the fact. A better way to make a good square is to use some square reference before cutting.

This square reference can either be the square fence of a tablesaw, the square edge of a factory cut sheet like a 4x8 sheet or a good certified square.

 

[sw1211]

Parallel guides will make 2 opposite sides parallel and then use your MFT to square up the other sides.  If you're using a Tablesaw as long as you have one true edge you can reference that edge against the fence to get the opposite edge parallel then use a sled to square the other two sides.

 

[Corwin]

Checking diagonals worked fine for checking that the frame for a wall of a house was square (well, rectangular actually) before applying plywood and raising.  And the 3-4-5 thing was great in checking that the string lines for a foundation were positioned accurately.  A carpenter's square is just too small for those tasks.  But for cutting down plywood ....................  get an accurate square.  Usually you will do as Steve mentions above, but there are times when you won't be cutting on your MFT.

 

[suds]

Ahhh, I'm starting to see what you mean.  I don't have a table saw and don't have the room but have the MFT1080 and have been playing around with Qwas Dogs to help visualize what we've discussed here.  If by using a known square reference on the table I should be able to produce a square panel?  I've read and reread Jerry Work's method, but since I have the dogs I think I can get the same results? 

 

[danrush]

I might add that one could ask:    How square does it need to be?  When is a cube (cabinet box)  really a perfect cube? 

We all want to be as accurate as possible, but work does need to be completed at some point.  I would contend that if the five panels on a cabinet box (excluding the face) were all out of square by 1/64", it really wouldn't amount to a hill of beans, once assembled.

Many here ( on the forum, not just this thread) seem to be caught up in getting down to machinist standards for measurements and square.  In the "wood" world, tolerances are just not that tight.  When a 64th or even 32nd of an inch might as well be a mile in one world, it's pretty darn close in construction.  ( buildings or cabinets)  Heck, take a piece of wood from one room to another and it may grow or shrink by 1/2 that much.  Now go outside, or wait for spring or winter, etc.

I install cabinets, from some very highly respected and meticulous manufacturers, and guess what:  The contractural tolerances allowed for size is from 1/16" to 1/8"!!!  The boxes all seem to install and perform well, despite the variances described. 

A quality framing square will get all but the most demanding craftsmen close.  After that, a properly tuned mft will take it to levels that probably cannot be measured in realistic, real world conditions. 

Dan

 

[clintholeman]

@Dan-

Amen to that!!! ;D

 

[Qwas]

Ahhh, I'm starting to see what you mean.  I don't have a table saw and don't have the room but have the MFT1080 and have been playing around with Qwas Dogs to help visualize what we've discussed here.  If by using a known square reference on the table I should be able to produce a square panel?  I've read and reread Jerry Work's method, but since I have the dogs I think I can get the same results? 

Yes the Qwas Dogs can be used to test for squareness by using 2 pairs, 1 pair in a horizontal row of holes and the other pair in a vertical row of holes. Here is an example from my pre-Qwas Dogs days:

[attachimg=1]

Also, the corners of the MDF top should be perfectly square if you ever need a quick reference.

All of this is covered in my old PDF file about the bench dogs that can be found here:
http://festoolownersgroup.com/CoppermineMain/albums/Manuals/Festool_MFT_-_Secrets_Unveiled.pdf