I am making a bookcase and dresser to go with a bed. The carcass is just a basic open box. I have to cut 1/4, 1/2, 3/4, and 5/8 veneered plyboard. I usually work with smaller stock. This is 4x8 foot sheets. I have found the tablesaw fence moves out of square. The boards are so out of square that I can't even use my 6ft T square as a starting point because I don't have one straight side to start with. Am I over thinking this? Is it this hard? I have tried planing by hand and machine, using the scroll saw to clean the edges, sanding for hours. This is ridiculous. Would someone be so kind as to give me some instructions.

You are asking a hand circular saw to do the work of a table saw. Your plywood sheets are square and straight when you buy them, use one sheet clamped onto another to create a straight edge. A scroll saw is the last thing to use to straighten an edge. If you must use a 12" block plane or electric hand planer.

I have a table saw and the fence is notoriously out of square. That was what I first started with. You might be right that the sheets are square when you buy them. I don't know that I believe it but I'll assume you are right. Perhaps it is the bow and warp that causes them to be off. I like the idea of a guide board and I use them when I router to prevent tearout on edges but how would you begin to clamp boards this size together. It is 4ft x 8 ft to start and 5/8 thick so it isn't all that easy to work with.

You can almost always solve problems by throwing enough money at it, but I'm cheap.

One old-timer trick is to use a Sawboard (http://members.aol.com/woodmiser1/sawbd.htm) and a circular saw. That will get you one straight edge that you can then use to put against your table saw fence. If you cut the plywood slightly wider than necessary, you can run the circular saw cut back through your table saw to clean it up (my circular saw cuts aren't always that smooth).

If you have an inexpensive table saw, THAT might be your problem. In that case, I'd use the sawboard exclusively. Just hold your circular saw firmly.

Best of Luck,
WallyH

I am making a bookcase and dresser to go with a bed. The carcass is just a basic open box. I have to cut 1/4, 1/2, 3/4, and 5/8 veneered plyboard. I usually work with smaller stock. This is 4x8 foot sheets. I have found the tablesaw fence moves out of square. The boards are so out of square that I can't even use my 6ft T square as a starting point because I dont have one straight side to start with. Am I over thinking this? Is it this hard? I have tried planing by hand and machine, using the scroll saw to clean the edges, sanding for hours. This is rediculous. Would someone be so kind as to give me some instructions.
I knew I was missing something. That's it! Problem solved. Thank you soooo Much!!

Recommend that you purchase both a 4' and an 8" straight edge. These come in a number of styles from just a flat piece of aluminum to styles that have intergal clamps.
I have the 50" Clamp and Guide and a 8" cheap aluminum guide from Sears that I have had for over 20 years. You could of course make you own by ripping off strips of plywood about 3" wide.

Next make some spacer blocks. The spacers will help you set the edge guide the correct distance from the line you want to cut. The spacers can be made from 1/4" luan, 1/4' plywood
or 1/2" plywood. I made mine from 1/4 Plexiglas. These spacers will be the exact
Distance from the edge of your saw shoe to the blade.

Start making you spacers by cutting a 6" X 6" square of the material you are going to use.
Clamp a edge guide to a clean work surface such as your workbench.
Measure the distance from you saw blade to the wide edge of the saw shoe. Clamp the
Edge guide about 1" less than that from the edge of the workbench.
That's so that you won't cut you workbench while cutting you spacers. Place your
Material on the work bench butting it up against the edge guide. Secure it with double sided tape (carpet tape). Using the saw and the blade for which you are making the spacers and cut the material with the wide side of the saw against the edgeguide..

Reposition you edge guide closer to the edge of the work bench, something less than
The distance between the saw blade and the narrow side of the saw shoe. Turn your material 90 degrees and reattach to the workbench with double sided tape. Make a cut with the narrow side of the saw against the edge guide. You now have one spacer, one side of which is the exact distance between the saw blade and the wide edge of the saw shoe, the other side the exact distance between the saw blade and narrow side of shoe. Remove that spacer from the workbench and make a second spacer from the remaining material, making sure to keep it properly oriented.

Purchase two small spring clamps.

To use your edge guide and spacers;

Measure and make a fine pencil mark on each end of your material.
Place you spacer on the keep side of the mark. The spacer always goes on the keep side.
If you wish to use the wide side of the saw against the edge guide, use the long dimension
Of the spacer.
If you wish to use the narrow side of the saw against the guide, use the short dimension
Of the spacer.
Clamp spacers in place with the spring clamps.
Place you edge guide on the material butted up against the spacers and clamp in place.
Remove the spring clamps and spacers.

Make your cut.

The accuracy of the cut will be within the thickness of the pencil marks.

The spacers work for that saw and that blade only. If you change a different kind of
Blade you will need to make spacers for that blade.

You can almost always solve problems by throwing enough money at it, but I'm cheap.

One old-timer trick is to use a Sawboard (http://members.aol.com/woodmiser1/sawbd.htm) and a circular saw. That will get you one straight edge that you can then use to put against your table saw fence. If you cut the plywood slightly wider than necessary, you can run the circular saw cut back through your table saw to clean it up (my circular saw cuts aren't always that smooth).

If you have an inexpensive table saw, THAT might be your problem. In that case, I'd use the sawboard exclusively. Just hold your circular saw firmly.

Best of Luck,
WallyH

I noticed the Sawboard website has disappeared. Here is a link to an archived version: Wayback Machine (http://web.archive.org/web/20071104151835/http://members.aol.com/woodmiser1/sawbd.htm)