How do you cut truly square largish sheet stock?

[Ron Bontz]

Well for my little bit. I first rip two parallel edges on my unisaw or one good edge. I then carefully measure the parallel edge and get it close with a circular saw if my unisaw is not available. A good straight edge like those straight edge clamps work pretty well as guides. I measure it off and use a spiral cut flush trim router bit. This gives me a nice clean edge. A good framing square and I repeat the process for the adjacent sides. If it is not more than my table saw capacity I only square one edge with the router edge guide then rip the parallel edge. I check for squareness by measuring diagonally.

[glenn bradley]

I built a mondo-task-specific sled for just such a project. I thought I would cut it down but I built a medium sized one before the project was complete so I still have it. Its about 3' x 4' made from BB ply with oak runners. When not in use it leans up against the small DC that handles the TS.

I only have to move it for use or to empty the bag so it is happy there and REALLY handy for those 'more often than I thought' larger panel cuts. Once I exceed that capacity I use shop made circ-saw guides and a tuned framer's square.

[Brook Duerr]

I have a a vertical panel saw so that helps a ton, but when I don't want to use the panel saw I used masking tape rubbed down real hard on the place I want to make a cut. Two layers works better than on. I mark the line and use a straightedge with my normal circular saw and I get decent cuts on 95% of most plywood. If I do have a problem with certain plywood then I use the saw to get close and the table saw to clean things up.

[Roger Warford]

Chris,
This is the most important step in cabinet making.
If you start wrong, the whole cabinet comes out wrong and you may spend more time adjusting the doors then making the cabinets.
My problem for over 20 years.
I hope this video can give you some ideas.
Same thing can be done with a simple jig.
Just make sure you screw the square -square to the straight edge.
Enjoy.
http://youtube.com/watch?v=ZFi80yzUHR0

Dino, what's that handy little jig you are using?

[Doug Hobkirk]

One solution that works comfortably on full sheets of plywood (5x5 or 4x8) -

• setup a cutting bench - I have a 4x8 grid made of 4" plywood strips setup on a plywood base that takes 3 minutes to assemble and 2 to dismantle - but I am switching to an easier to use "Smart Table" from EurekaZone
• put the Freud Diablo 40-tooth blade on my squared circular saw
• mark the cut at both ends - I line up the saw guide edge barely over the marks or the kerf of the blade shy of the line depending on whether my rail is on the keep piece and how I made my mark (but the main point is that it is accurate to 1/32" so the width of the mark is an important issue to pay attention to)
  • Melamie? make a scoring cut first by running the saw backwards at 1/16"
• now I have two parallel edges with no chip-out
• the square on my saw guide (by EZ) is very accurate - it's setup the same way you test a standard big square - I cut off however little I can at the end to make it square
• Measure, mark (I only need one mark but I usually make 2 marks for reassurance), and cut
• repeat until everything is cut
• store the "smart table"

[Randal Stevenson]

Dino, what's that handy little jig you are using?

That is the EZ which has a forum down below. Dino owns the company (I thought that was in his signature).

[Brian Tuftee]

I've always relied on a factory edge for squareness, so all bets are off if the sheet is junk to begin with. Believe it or not, I use a very simple setup, an aluminum L-shaped bar that's 4' long, attached to a sheet of 3/4" plywood. Kind of like a cutoff sled, I set the edge of the plywood right on the cut line, scribe the cut line carefully with a knife, then cut with a circular saw with a plywood blade. The plywood backs the cut up, and along with the score line, I really don't see any tearout on face veneers.

Usually though, I will rough cut the plywood without a guide to the approximate shape I need, and then run those smaller pieces through the table saw (using the factory edge again) to get my final cuts.

[Bill Jepson]

I do have a Festool 55 Circ Saw & rails. The thing that may have been said in the other threads is that the Festool is that they have an edge that is actually cut by the blade so that it prevents chipping on the edges. The saw also has a back up to the blade on the outside too. Works great. Unfortunately it IS very expensive.
The way to acheve nearly the same results for a lot less money it to but about a 9' aluminum bar and clamp it to your stock and measure to the blade to get a straight cut with your regular circ saw. I worked at a large national research lab. We needed to cut lead plywood sandwich material.
This was for radiation shielding so gaps were, how would I put it, BAD! We used a 1/2 x 4" x 9' bar checked for straightness and used that and a square to produce VERY accurate results. Standard Skil circular saw. Put the edge next to the bar. Very simple system. All the guys worried about wood dust (justifiably) should see what the regulations on lead dust are like!
Bill J

[Jim Kirkpatrick]

I use my unisaw with 50" bies. fence. A 2 minute process.

[Chris Bruno]

Hi Jim, my concern is the squareing of the piece, not so much the ripping. Unless you have another step, you're still relying on the factory corner to be square.

I like Dino's solution the best, honestly, but I priced out an SGS-2 with the fancy square and handle on the Eurekazone webpage and at $270 I'd be half way to the Festool.

I guess I'll try to make as fancy a circular saw guide as I can with the T-square idea and see how it goes. I'm getting the impression from the responses, though, that there's probably a majority of people who just rely on the factory corner to be square. Hmmm..

Thanks everybody!
-Chris

[Bill Jepson]

I use my unisaw with 50" bies. fence. A 2 minute process.

Jim, Fine if you have one and the space to use it. I would maintain that even if somebody has a nice TS and the wide fence capacity that many people have trouble with large sheets on the TS. I was ripping some 3/4" oak ply for a table top over the week end and if doing it by myself would still prefer the rail and circ saw to the TS. It can be tough to keep the sheet square to the fence and heavy to push through. Lots of people can have trouble lifting thick 4 x 8' ply sheets if they are 3/4" or thicker. I'm not a small guy and would still prefer the Festool OR the regular rail and circular saw to the TS for sheet goods since it is easier to control. No knock on the TS either, just saying for me the rail system is easier.
Bill Jepson

[Mike Spanbauer]

Full sheets, I use my festool TS55. If I'm going for dot on 3x3 square I'll cut a little oversized and then use my PM66 w/ Jessem slider.

It is challenging to get 36" x 36" with hand methods unless you're patient. And then anything is achievable.

As long as it isn't production (time) oriented just get a nice straight edge and a good new blade on the circ saw. I personally used to use the 40tooth Freud for my skilsaw and it worked fine. Yes, you do get a little chipout, but it's not that bad. And if you're really worried about it, you can just hit the edge over at the jointer aftewards with knives set to 1/32" (after cutting the panel 1/16" large in both x and y)

Mike

[Steven Wilson]

Well, I just toss the sheet up on my MiniMax CU350 w/ 8.5' sliding table and cut it square (trim one edge and then rotate that up against the fence). No problem, perfect panels every time.

[Jim Kirkpatrick]

Hi Jim, my concern is the squareing of the piece, not so much the ripping. Unless you have another step, you're still relying on the factory corner to be square.

I like Dino's solution the best, honestly, but I priced out an SGS-2 with the fancy square and handle on the Eurekazone webpage and at $270 I'd be half way to the Festool.

I guess I'll try to make as fancy a circular saw guide as I can with the T-square idea and see how it goes. I'm getting the impression from the responses, though, that there's probably a majority of people who just rely on the factory corner to be square. Hmmm..

Thanks everybody!
-Chris

What I would do is make first rip wider than 36", turn work pices around so newly cut side is against fence, reset fence to 36" and make sencond cut. Repeat the process for other 2 sides. If your fence is accurate, it works like a charm.
For those that don't like to wield large sheets of plywood on table saw and don't own a Festool saw throw it on some saw horses and rip and crosscut to rough size (an inch or 2 larger) with a circular saw, then do table saw steps described above.

[Randy Klein]

Dino, what's that handy little jig you are using?

Oh just a little something something he threw together...

But seriously, www.eurekazone.com.

Or just check out the forum.