2nd Carcass and 2nd time not being square

[Adam Cavaliere]

I have now created 2 different things for my shop that required a carcass to be built for drawers height. This last one was the router table seen on the New Yankee workshop. After getting some of the drawers made, I have come to the realization that it isn't fully square. On this project I even tried to be as careful as possible. It still isn't completely square from front to back. This means my drawers with their glides are going to be off and that will be a pain to fix.

I would love to hear some tips from you guys on assembly to make sure that the carcass is fully square before gluing up. I am super frustrated right now!

Any small projects you can think of to help me practice before I run into this again on a bigger important project to me?

[Danny Thompson]

So the front is wider than the back? Is the cabinet bottom square?

A nice single-drawer project is a drill press table. And if you goof it up, no one will be the wiser.

[Jim Rimmer]

I always dry fit and clamp and check for square (and fit) before gluing.

[Leo Graywacz]

You need to check everything from step one to the last step. Are all your pcs square? Check'm corner to corner. When you assy them you need to check corner to corner. Sometimes the clamps get in the way, check the inside dimension instead. Using a square might not work while under clamping pressure. Panels will bow slightly under pressure. If it is not square you can offset the clamps a few degrees on one end to pull it into square. Once the glue dries it should stay.

It took me about 3 years to learn that it needs to be square in all 3 planes. After that clicked things were a lot smoother. They also have to be flat and true, but that is another lesson.

[glenn bradley]

Good recommendations here. As a relatively new hobbyist, I have had the experience you are having. As mentioned, for square work your pieces must be square. If you have to persuade pieces to join correctly, remake the offending part. Something else that used to get me (and I know this seems sooooo obvious), assembling parts on a non-flat surface (like the garage floor).

I have, of course, just plain old goofed up plenty too. I now know a few methods/steps that if followed carefully, improve my success rate; square parts, a flat assembly surface and good dry fit before gluing anything.

P.s. Just remember, this is only your second carcass, it'll come.

[Mike Cruz]

Dittos on two accounts! Measure your diagonals and assemble on a flat surface.

If one diagonal is longer than the other, put a clamp across the longer of the two diagonals...drawing it in until they are the same. Support the carcass above your assembly table (with a couple of EQUALLY thick boards or something) and check the bottom as well as the top. Put clamps on top and bottom or where ever you need to draw in. (Hope that made sense.)

A bunch of you guys may jump all over me for this one but here it goes: If you need a TRUE flat surface...use your table saw. Just make sure you don't get glue all over that nice surface...the table saw's, that is. Likely, no other surface in your shop will be as flat as your table saw.

[Dave Sharpe]

go back to the beginning and check your tools themselves. On a tablesaw, for example, be sure your fence is square to the blade, and that your miter guage is actually set at 90 degrees. I sometimes rely on them too much for square cuts and then later find that they're off by just a bit. On a chop saw, make sure it is adjusted properly for 90 degree cuts as well - even just a bit off can add up quickly with several cuts.
When measuring, are you taking into account the Kerf consistently? I've been known to forget this as well, with the result being that one end of a cabinet or box is slightly wider than the other end.....
Keep at it - each "failure" is a learning experience (I once put in two windows in my wife's art studio, and the second is hung much straighter than the first one. I tell her it's not crooked - it's just a visual representation of my learning curve...)

Dave

[Peter Quinn]

If you are all glued up it is going to be hard to do an autopsy on the present carcass. If you are out of square front to back pay attention to your top and bottom panels, which may be out of square, and if using dado construction, I have seen plywood thickness that was off by enough to throw things out of square, not much I can recommend there except watch out for that.

For instance I had a sheet not long ago, A-1 pre-finished maple, 3/4", I cut my parts for a standard box size, 23 1/4" depth, my sides measured .720" along one edge, .745" along the other. If two sides both taper .25" over their width, that is working on an easy 1/16" over 23", not great but not the end of the world either. Even with an over arm router or CNC the error will still present it self to the interior of the boxes.

Take a close look at your method for breaking down sheet goods, make sure things are coming off the saw square, then focus on clamping strategy and make sure you aren't causing any problems there with over clamping or misalignment.

[Dino Makropoulos]

The problem is the panels.
They don't come square from the mill.
The other problem is your tool. (tablesaw?)
Designed before the panel technology for parralel cuts.(rip cuts)

Your very first cut( For each part ) must a trimming/squaring cut.
Easy to do with a good framers square, a straight edge and a circular saw.

good luck next time.

[Jim Kappel]

I struggled with carcasses too. I made the leap to a better table saw and made a panel cutter. Both have increased my carcass building a ton.

Like someone else said, only 2nd one. It gets better.

Jim

[Eric Garner]

This happened to me when I first got into woodworking. My problem was how I cut up my plywood on the table saw. My problem was not squaring after rips were made. I was using the fence to make all my cuts.

Here is the sequence I follow now and end up with square panels used for my carcasses.....


1. Rip all pieces to uniform widths.
2. Square one side using cross cut sled, miter gauge, or miter sled.
3. Measure your lengths from the squared side setup your stop block on the saw and using cross cut sled, miter gauge, or miter sled cut the other side to bring the panel to length.


This assumes your sled, miter gauge, etc is square to the blade.

[Chip Lindley]

Every small error adds up! Fine-tune a steel framing square to within an .05mm lead pencil line, and you have a very accurate means of checking panels for squareness.

(Fine-tuning the square is a subject well-covered in other threads)

Unless you have a very-well-tuned TS sled for crosscutting, Use another means to crosscut your panels. The TS fence will not give you an exact square cut, without an exhausting adjustment process.

Before my Exaktor sliding table, any crosscuts wider than 12" were done this way> I took sheet goods outside and laid them on 2x's on sawhorses. Marked *square* cut lines, and used a clamped straight edge and fine-tooth blade in the *Skilsaw* to crosscut. In practice, *IF* your panels are within 1/32" over 24", everything will fit together adequately.

[Adam Cavaliere]

Hey Guys,

Thanks so much for all of the recommendations and encouragement!

I definitley need to find a better surface than the garage floor for assembly, but right now it is hard to figure out where to get the space for an assembly table :)

I did notice that my sheet goods weren't the best. Maybe I'll have to reconsider purchasing from Menards.

It is suprising to hear that the table saw fence is assumed to not be good enough for accurate rip cuts. I do notice that it toes out slightly at the end, but from what I understand, this is by design and therefore accurate at the point of the cut.

Just for reference, I have a steel city table saw with the upgraded fence.

I will try to get a better long square for checking squareness.

I have also considered building a crosscutting sled, but have wondered about how long of a sheet I could really get to cut with one. What is the maximum lengths you guys to try and cut with your sleds?

[Don Morris]

Excellent advice above. You need to incorporate most all of them. Dry fit is one size, glued is another so the comments about measuring during the glue-up and applying appropriate clamp pressure is sooooo true, ask me I know. Measure as you go along, don't wait until the end and hope. This craft is just that...a craft that takes some experience to work out the "bugs" and techniques. You just can't walk into perfection. At least not in my experience.

[Leo Graywacz]

I have also considered building a crosscutting sled, but have wondered about how long of a sheet I could really get to cut with one. What is the maximum lengths you guys to try and cut with your sleds?

I can do a 25 x 94 1/2" pc on mine. But it is really pushing it. Anything less than 70" long is done with ease. I have my sled on both miter slots and the shortest board I can cut using the fence is about 18". After that I have a 20" spacer and I reference everything from the 20" line to get cuts down below 18" Works great for me.

[Jerome Hanby]

Measuring diagonals is a good way to find out that some of your squares aren't square after all. That information is really discouraging when you payed upwards of four dollars for that square:eek:.

[Rod Sheridan]

Measuring diagonals is a good way to find out that some of your squares aren't square after all. That information is really discouraging when you payed upwards of four dollars for that square:eek:.

Jerome, thanks for the entertainment, I haven't laughed so hard in a while.....:D

Regards, Rod.

[Lee Schierer]

I helped a young man make a pair of night tables for their bedroom. He always wondered why I kept telling him to check everything for square throughout the project when we went to make the drawers, it was "check every thing for square"

He figured out the reason when we went to mount the drawers in the openings. They fit first time and the front sat nicely agianst the face frame.

Start from teh beginning to check all saw settings for square. My factory miter gauge was off true 90 by over a degree. Not a problem for most contractors, but it sure matters for cabinets. I keep the following tools, known to be accurate at hand when making projects:

1. Platic drafting triangles - cheap but highly accurate
2. Starret combination square - not cheap but much better than the cheap ones
3. Carpenters square, checked for accuracy, they don't all come that way.
4. Tape measure - for checking diagonals of all glue ups.
5. Beall Tilt Box

[Bill Houghton]

If one diagonal is longer than the other, put a clamp across the longer of the two diagonals...drawing it in until they are the same.

As someone else mentioned, it's critical to check that your components are square and of equal length before applying the diagonal-measurement test. If the top board of a carcass is 1/4" shorter than the bottom one, you can get the diagonals to be equal, but your carcass will be a trapezoid, not a rectangle.

[Danny Thompson]

Hey Guys,

It is suprising to hear that the table saw fence is assumed to not be good enough for accurate rip cuts. . . I have also considered building a crosscutting sled, but have wondered about how long of a sheet I could really get to cut with one. What is the maximum lengths you guys to try and cut with your sleds?

To be clear, a table saw fence is an accurate reference for acheiving accurate/parallel rip cuts. But a table saw fence can not be used to guarantee accurate/perpendicular crosscuts.

A fence only guarantees that the saw blade cuts parallel to the edge of the board that is tracking along the fence, but does not guarantee that the leading or trailing edge is parallel to the blade.

So, if you use the table saw fence as your reference to cut all four sides, the two opposite sides will be parallel to one another, but they will not be perpendicular to the adjacent sides. Your finished board will be a a parallellogram, but not a rectangle.

To guarantee a square crosscut, you must first rip one side, then register that side against a jig with a fence that is adjusted 90º to the blade. The most common examples are a miter guage and a crosscut sled. A crosscut sled is generally more reliable because the fence supports the full width of the board--reducing the tendency for the board to twist through the cut.

I strongly recommend you build or buy a crosscut sled and carefully adjust the fence to 90º. It will transform your work and greatly increase your enjoyment.