cabinet panels are not square!

[Jeff Kerr]

Ok,

So somehow I didn't check things well enough and I have found that my plywood panels for a shop cabinet are not square.

I have already rabetted them for the back, but when I measure diagonal I am off by a strong 1/16" on both of the side panels. I haven't measured the top and bottom panels to see if they are also off.

My question is, how do a fix it? It seems to me that if I run them against the saw fence again I will merely have another straight side that is still off.

Should I use my cutoff sled and pick one orientation to be true and square off of that? If I use the rabet edge as square do I need to cut the other 3 to make sure I am square on all sides and then make final sizes after that?

Since it is a shop cabinet I can lose a little in size with no problem. I found out when I dry fit it that there was no way I was going to square it up with clamping.

[frank shic]

jeff, where do you think the problem lies? is your table saw fence true? is your crosscut sled perpendicular to the blade? i never had problem making rip cuts with equal widths on either end but the miter sled gave me all sorts of grief and imperfections which i why i replaced it with a sliding table. try using the five cut squaring method to see how far off your sled is - i'll bet that's where the problem lies.

[Cliff Rohrabacher]

You are out of square at the saw.
cut a 2 or 3 foot square piece of plywood using the five sided method and true up your fence.

[David DeCristoforo]

Your best bet is going to be to re-cut all of the panels square. Even if you have to adjust your finished sized a bit. But, first, make sure (in this order) that:
A) your miter slot(s) is parallel to your saw blade
B) your fence bar (the one that the fence slides on, not the fence itself) is at 90 degrees to the miter slot and that
C) your fence is parallel to the saw blade.

Then make a few test cuts and verify that the machine is actually cutting square.

[Phil Thien]

Your best bet is going to be to re-cut all of the panels square. Even if you have to adjust your finished sized a bit. But, first, make sure (in this order) that:
A) your miter slot(s) is parallel to your saw blade
B) your fence bar (the one that the fence slides on, not the fence itself) is at 90 degrees to the miter slot and that
C) your fence is parallel to the saw blade.

Then make a few test cuts and verify that the machine is actually cutting square.

I don't know why he should concern himself w/ (B), as long as (C) holds true. You can still have a parallel fence when the rail isn't perpendicular. The rail needs to be straight, that is really the only requirement.

I would: Make sure your miter slot is parallel to the blade, and your fence is parallel to the miter slot.

Next, make sure your cross-cut sled is cutting square. You can do the five-cut test like some have suggested. However, making a test cut and checking it with a large, trusted square is just fine.

I suspect your plywood wasn't square when you got it. I further suspect you used your fence for nearly all the cuts (as they are large pieces). So now nothing is square.

So you should have parallel sides, at least. I would use that cross-cut sled to clean-up the panels and next time check your plywood before you even cut into it.

[Bob Feeser]

By any chance did you reference one side, and make a 90 degree cut. Then use the freshly cut surface as a reference, resting against your fence, and make another 90 degree cut, then flip the board around, referencing off of the second cut surface, and make another 90 degree cut? Technically, if you have a perfect, and I mean perfect 90, you can actually do that, but if you are off by just 1/2 of a degree, by the time you get to the last cut, it will magnify the error, and you will be off sufficiently to get some unacceptable results.

It's like you take a sample piece, then keep referencing off of the newly cut piece, until you get to the end, and try stacking them all up, and find that they are way off.

It's like you whisper something in someones ear, and they whisper it to the person sitting next to them, then they whisper it to the next person. Then by the time it gets around the room, it barely resembles the original message. :) I hope you are having as much fun reading this, as I am writing it. :D

I realize that this may not actually be your problem at all, but it is worth mentioning. If it is in fact the problem, then try jointing an edge, then using that jointed edge as your reference against your table saw fence, and cut your opposite side. Now you have 2 perfectly paralell sides. Then you can reference off of either side, to make your 90 degree cuts. If it is still off after you do that, something is not set right. Then you get back to basics, and critically check your settings.

I'm aware that I could be blabbing a bunch of stuff you probably already know, but that is my input, since everyone else, seems to have covered the other possibilites.

[Art Mann]

Most people have focused on how to fix your equipment so that it cuts square. I am thinking you are asking how to fix the panels you have already cut. The first thing I would do is ask myself whether a 1/16" discrepancy in the diagonal measurements will matter. My experience has been that such a minor discrepancy will have no effect on the end product. If I were you, I would continue on with the project and resolve to correct the equipment or technique problems on the next panel.;)

[Phil Thien]

Most people have focused on how to fix your equipment so that it cuts square. I am thinking you are asking how to fix the panels you have already cut. The first thing I would do is ask myself whether a 1/16" discrepancy in the diagonal measurements will matter. My experience has been that such a minor discrepancy will have no effect on the end product. If I were you, I would continue on with the project and resolve to correct the equipment or technique problems on the next panel.;)

That is an excellent point! 1/16" over several feet shouldn't cause a problem.

[frank shic]

excellent point, art! jeff, if you're doing face frame style cabinets, it's not going to be too obvious unless you stick your head inside the cabinet and look around. once the countertop is installed on top and the doors are in place, no one but you will know the difference.

[Steve Clardy]

Most people have focused on how to fix your equipment so that it cuts square. I am thinking you are asking how to fix the panels you have already cut. The first thing I would do is ask myself whether a 1/16" discrepancy in the diagonal measurements will matter. My experience has been that such a minor discrepancy will have no effect on the end product. If I were you, I would continue on with the project and resolve to correct the equipment or technique problems on the next panel.;)


Amen!!!

I wouldn't worry about it :D

[Gary Keedwell]

:D
Most people have focused on how to fix your equipment so that it cuts square. I am thinking you are asking how to fix the panels you have already cut. The first thing I would do is ask myself whether a 1/16" discrepancy in the diagonal measurements will matter. My experience has been that such a minor discrepancy will have no effect on the end product. If I were you, I would continue on with the project and resolve to correct the equipment or technique problems on the next panel.;)
I am glad you said what I was thinking;)
Gary K.

[Jeff Kerr]

Art and crew,

You are correct. I was lookg for how to save the panels I have already cut.

I do appreciate the tips on checking my tablesaw for square and I will do that just to make sure.

In this particular case I have come to the conclusion that I was bit by some ply that was warped. Ultimately, I was able to persuade the pieces to pretty darn close to being square. So I went ahead and glued it up.

SInce I was going to use this for the shop I felt that it was close enough for Jazz :D .

Anyway here are a couple of pics. It tucks nicely under the tablesaw.

Thanks for all the pointers. I will be tuning up the saw and fence ets this week.

67364 67365

67366 67367

[Steve Clardy]

Nice looking cabinet Jeff!!