How do you cut truly square largish sheet stock?

[Chris Bruno]

For the NYW router table, I needed an approx 3'x3' sheet for the back. I used the factory edges to get the straight sides, but both dimensions were larger than could fit in my cross cut sled, so I had to rely on the factory 'squareness'. Not surprisingly, it wasn't perfect.

How do you guys manage this problem? And I mean, truthfully manage it - not what you know you should or could do.. I mean, I know I could break out the circular saw, but the tear out is worse and the setup time to get a nice straight, square edge would be really long. Another option would be to just deal with the non-squareness, and that's basically what I do now except that I feel like my less than perfect sheet goods cuts is a big detractor in my projects (drawers don't end up fitting perfect, etc).

I can't imagine that everybody has built enormous in-feed tables to support oversized cross-cut sleds or installed sliding tables..... have you?

Frustrated in Metrowest Boston...
-Chris

[Kevin Ladenheim]

The FESTO MFT and plunge cut saw works for me. I had terrible luck with a regular circular saw and guide. And my shop is too small to get any substantial part of a sheet through my table saw. Having infeed and outfeed tables that could support a 4 x 8 sheet would be a lot easier and way, way cheaper than the FESTO equipment though.

[Brian Walter]

Chris,
I made a sawboard for use with my circular saw and attached a length of 2" x 2" material to the end of it to essentially turn it into a large "T-square". I adjusted the squareness using the 4 cut method, it is square to within 1/32" or less over a 4 ft distance. The zero clearance aspect of the sawboard results in very smooth, nearly splinter fee cuts. I think any of the better saw guides would provide similar if not better results.

Brian Walter

[Chris Bruno]

Thanks Brian, that's a good idea for the T-square. As much as I'd love a Festool, I don't see it happening anytime soon. I think I may try to build a sawboard like yours this week... I must say, though.. setting up the saw horses isn't going to be fun everytime I need to cut a larger piece. Maybe its time I build a cutting/assembly table, too.

AAARGH - where am I going to keep all this stuff. :)

-Chris

[Ken Fitzgerald]

Chris.... draw it out on the sheet stock. Find a board with a good straight edge. Clamp it to the sheet stock and use it as a cutting guide for a circular saw.

[Jamie Buxton]

Three tools: a measuring tape, a guided circular saw, and a tuned-up framing square.

The guided circular saw can be a high-end one like Festool's, or it can be a shop-built one. (The shop-built version costs considerably less.) The point about the guided circular saw is that it cuts straight lines.
The tuned-up framing square is exactly 90 degrees. The error in mine is about .005" in 24". The basic square is a $15 Stanley. Tuning it up took an hour or so.

[James Hart]

Chris,

For a panel that size, I rip all four edges. Just did it tonight with a bunch of 5' x 5' baltic birch. I use board buddies set pretty aggressively to hold it to the fence. I'd rip oversize by 1/4" with the factory edge against the fence, then flip it over and trim the other side to finished size.

I only use the crosscut sled with solid stock or cuts where I would be cutting the width of a sheet that's more than a little bit longer than it is wide.

Jim

[Greg Hines, MD]

Here is a photo of my saw guides. I made a pair of them to use with my circular saw or router. They work great.

Doc

[J. Z. Guest]

...How do you guys manage this problem? And I mean, truthfully manage it...

a) Confirm one factory edge is straight with a straightedge

b) If there are no corners square to a straight edge, you'll have to make one. Set up your saw guide with your (truly square) carpenter's square, clamp it down. To make the cut without tearout, scribe the cut line with a knife. Careful not to gouge into your aluminum edge guide with the sharp steel blade. If you don't want to do that, you can use a cheapie plywood blade and feed the circ saw slowly. Get ready for a lot of choking sawdust.

c) Now, you have two straight edges that are square to one another. Mark the third edge from the first edge. (ex. 36" from the first straight edge at several points and draw a line.) Cut the line with the same method as in b)

d) Repeat b) with the fourth edge. Now you've made a square sheet because you used the same straight edge as a reference for all the cuts. (no cumulative error by using each previous edge as a reference)

Yep, it is a pain, but not having a square piece for the back may throw your whole cabinet out of square, which means lots of tedious hand-fitting everywhere, not to mention that it will only ever touch the floor at 2 or 3 corners at a time. If you're OK dialing this out later with leveling feet or shims under the casters, I guess you could get lazy.

As long as I've been asked to be truthful, I'll admit that I never end up with four corners/feet on the floor no matter how careful I am, so I can't imagine how much work it would be if I weren't careful to get things square. ;)

[Chris Bruno]

James, if I'm not mistaken, that will still just leave the squareness only as good as it was from the store. Am I missing something?

[josh bjork]

I plan to make a large plywood square. I once met an old woodworker that had made such a thing. One side will overhang so it is easy to line up. It will be both for reference and a cutting guide. I don't know that 3' is too big for a sled though.

[J. Z. Guest]

You're right Chris. This would work if it was already square to begin with. It would leave one with two sets of parallel edges, but not necessarily square.

Most likely, one would end up with a parallelogram masquerading as a rectangle, hehehe.

(not to mention that you already suggested it was too big to rip on your tablesaw, at least that's how I read it)

[James Hart]

Chris,

When I'm working on something where I really care whether it's 100% square, I'm also using a good sheet, usually Baltic Birch if you won't see it, or hardwood if you will. I take a square with me to check for at least one square corner and work from there, following the exact process I laid out.

I've never taken home a sheet of this quality that didn't have at least one square corner (I'm not saying I haven't seen more than a few.)

If I'm working with lower quality plywood, then I've already lowered my sights enough that I'm less likely to be bothered by somethings that's a degree out of square. I still check them with a square when I'm shopping.

Jim

[Dino Makropoulos]

For the NYW router table, I needed an approx 3'x3' sheet for the back. I used the factory edges to get the straight sides, but both dimensions were larger than could fit in my cross cut sled, so I had to rely on the factory 'squareness'. Not surprisingly, it wasn't perfect.

How do you guys manage this problem? And I mean, truthfully manage it - not what you know you should or could do.. I mean, I know I could break out the circular saw, but the tear out is worse and the setup time to get a nice straight, square edge would be really long. Another option would be to just deal with the non-squareness, and that's basically what I do now except that I feel like my less than perfect sheet goods cuts is a big detractor in my projects (drawers don't end up fitting perfect, etc).

I can't imagine that everybody has built enormous in-feed tables to support oversized cross-cut sleds or installed sliding tables..... have you?


Frustrated in Metrowest Boston...
-Chris

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.:o
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

[tim rowledge]

How do you guys manage this problem? And I mean, truthfully manage it - not what you know you should or could do..

I have a minimax CU300 so I just toss the sheet (even an 8*4; rippling superman muscles make it easy ;) ) on the slider, line up a factory edge and make a first cut. That gives one dead straight edge, so turn that to the fence and set the stop to the dimension (up to 100") and make a second cut, which will be square. Repeat with the next two cuts. Easy.

[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.:o
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...:D

But seriously, www.eurekazone.com.

Or just check out the forum.

[Chris Padilla]

Sqaure is overrated...just go with the flow. Wood is a natural product although plywood is not.... ;)

You want square: 3-4-5 triangle multiplied or divided as you deem fit. :) Take the time to make a reference and you'll be squaring up your stock faster next time.

[Roger Warford]

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

Ooops. Sorry Dino! I've been through the EZ forum and visited your site. Filling my piggy bank as we speak - looks like a great system you've put together! Hope to be able to do business with you soon.

Thanks Randy and Randal!

-Roger

[Cliff Rohrabacher]

Throw it on my slider.
Dead on every time.

[Ben Cadotte]

Sqaure is overrated...just go with the flow. Wood is a natural product although plywood is not.... ;)

You want square: 3-4-5 triangle multiplied or divided as you deem fit. :) Take the time to make a reference and you'll be squaring up your stock faster next time.

3-4-5. Dont trust drywall t-squares from the borgs or anywhere else. I went through at least 2 dozen of them at 3 stores before I found one square!

As for cutting I have a piece of angle that is straight that I clamp and use with my circular saw. I am in the market for a vertical panel saw and found one. But money became an issue.

[Noah Levy]

Sqaure is overrated...just go with the flow. Wood is a natural product although plywood is not.... ;)

You want square: 3-4-5 triangle multiplied or divided as you deem fit. :) Take the time to make a reference and you'll be squaring up your stock faster next time.

You got it. Good ol' Pythagorian Theorem, C squared = A squared + B squared. I use the 1, 1, square root of two triangle.

Say you need a 36" square back for a cabinet. Draw two parallel lines 36" apart. On the bottom line mark 36" length from point A to point B. Now the square root of 2 is 1.414, so 1.414 times 36" is 50.9", so measure out 50.9" from point A to the other parallel line you drew and the point of intersection on that other line call it point C. Drop a line from point C to point B on the first line and you got yourself one very accurate square corner. You can extend any of those lines for the height of the cabinet back you need. After that it's just a matter of using your tablesaw rip fence to cut lines parallel. Try it on a piece of paper so you are sure it works for you. THis method is very accurate and one you can visualize what you need to do, it is very quick. You can even make yourself a very large square from plexiglas for layout use.

[Chris Padilla]

3-4-5. Dont trust drywall t-squares from the borgs or anywhere else. I went through at least 2 dozen of them at 3 stores before I found one square!

Drywall is one thing that DOES NOT need to be square!! Hence the reason drywall squares, which only us non-pro homeowners use, are not square. :)

Keep in mind that 3-4-5 are ratios and can be of any unit you choose. For example, cut yourself 12 sticks of any length (but all must be the same length) and fashion a clever way to attach 3, 4, and 5 sticks together and you'll have yourself a perfect right-triangle. The devil is in the details but maybe this fires off a couple synapses for ya! :D

[John Gornall]

I made a bunch of cabinets last weekend. The 4x8 sheets go off the truck onto a few 2x4's on the driveway and get one cut across at a suitable dimension to make them easier to handle. Then into the shop and all rip cuts are done on the tablesaw. The front edge is banded and then they are ripped to final width. The back edge is rabbeted with a rabbeting bit in a router. Then the cross cuts are done using the Jessem Mast-R-Slide on the tablesaw. All panels are now to size and square ready for assembly.

[Rob Blaustein]

I use these saw horses (http://www.sawmillcreek.org/showthread.php?t=8083)--works great. I put a 4x8 sheet of old ply on top, then a 4x8 sheet of rigid foam insulation. The sheet I want to cut then goes on top of that and I use the Festool system. This all knocks down and takes up very little space in my garage when I'm done.

You are welcome to zip over to my place and check out the setup some time. I am probably 30-40 min from you. PM or email me if interested.

--Rob

[Karl Brogger]

http://www.cuttingedgemachinery.com/striebig_evolution.jpg

[Cliff Rohrabacher]

http://www.cuttingedgemachinery.com/striebig_evolution.jpg

Striebig Mmmmmmmmmmm