Crosscut long, wide stock

[Jon Endres]

How-to question.

I need to build some large cabinets for my basement, for storage. They will be about 7' tall, 16" deep and varying widths. I will need to crosscut the sides from 8' long pieces of plywood and can't figure out how to do so accurately. I don't have a sled for my table saw, and even if I did, I can't figure out how to support something off the left hand side of the saw that is eight feet long. My SCMS won't cut 16" wide. I've tried cutting halfway and then flipping the piece, they never match up well. Does anybody else have a good solution that will give me, A) a clean edge, and B) a square cut? Thanks.

[Mark Engel]

How about a circular saw with a straight edge?

[Chad Easterling]

Agree with previous post.... I use a good circular saw blade with a locking guide. Just make sure the "bad" or hidden side of the wood is up so any tearout will be hidden.

[Mike Wilkins]

I have seen Norm Abrams cut wide stock many times with a hand-held circular saw and a straight edge. Unless you have access to a sliding tablesaw and all the room it needs, this is likely the only way. Or get the lumber yard or store to pre-cut it in their facility. Most stores will cut your sheet stock; 1st and/or 2nd cuts free and a minimal charge for additional cuts. Or just go ahead and do what I did before I got a sliding saw; bite the bullet and get your hands on a Festool system. No regrets.

[Mike Wilkins]

Another thought came to mind. Make sure you can get 7' long pieces into your basement without banging up the walls and practicing your profanity skills. May need to consider smaller cabinets that stack.
Don't ask me how I know this.

[Thomas Pender]

Do you have a friend with a Festool and and long edge? (They have very long ones and the others can be attached to one another.) If so that will work and work well - I use that over a table saw any day. Alternatively, is there any shop nearby with a panel saw? Sometimes if you buy wood from a place they will have a panel saw as will most large lumber yards - you have to ask and be willing to use a good blade that you may have to buy.

Or, the time tested way, which is to get a reliable straight edge, some saw horses and use a reliable circular saw with a good blade and use the straight edge against the saw. One thing that works is a metal stud (heavy duty variety that is very stiff and very straight) - stuff at Borgs will be "bendy" and you want a very stiff edge.

[Jon Endres]

I probably should have mentioned that I have an EZ-Guide and use it all the time to break down larger pieces of plywood. I am more worried about a square cut. I honestly never thought about using the 50" long rail on a 16" wide piece, I guess my mind was focused on how to do it with my table saw. I suppose this was a wasted question, because a good framing square can get me the accuracy I need and then I can place the EZ-Guide on the line and cut.

I also have drafting squares I can use to get the line I need.

OK, thanks guys, back to your regular programming... :o

[Jamie Buxton]

I probably should have mentioned that I have an EZ-Guide and use it all the time to break down larger pieces of plywood. I am more worried about a square cut. I honestly never thought about using the 50" long rail on a 16" wide piece, I guess my mind was focused on how to do it with my table saw. I suppose this was a wasted question, because a good framing square can get me the accuracy I need and then I can place the EZ-Guide on the line and cut.

I also have drafting squares I can use to get the line I need.

OK, thanks guys, back to your regular programming... :o

For untwisted cabinets, you want high accuracy in that 90 degree angle. Being off a whole eighth of an inch in a 48" cross-cut amounts to an error of only .1 degrees in the 90 degree angle. I built my own very-accurate square to use with my guided saw. I built it for a Festool, but the concept should work just as well for an EZ-Guide. http://www.sawmillcreek.org/showthread.php?t=49778&highlight=straight+edge

[mreza Salav]

A large cross-cut sled with t-tracks cut/glued into it and hold down clamps works. I've done it (do it regularly).

[Charles Wiggins]

Jon,

If you have an EZ-Guide your in the fabled cat-bird seat. There are a couple of things I do to minimize tear-out. 1) Good quality blade designed for plywood. 2) Make the cuts in three passes. I adjust the blade so that the first pass cuts through only the first couple of plys, the second pass goes most the the way through, and the third is adjusted to cut just beyond the bottom ply. 3) I make my cuts on top of some 3/4" or 1" foam insulation. I just set it on the floor and put the workpiece on top of it, so when I make that final pass the piece is fully backed up and supported all the way across the cut.

Charles

[Sean Nagle]

This is a job for a radial arm saw ;)

[Mark Bolton]

Jon,

If you have an EZ-Guide your in the fabled cat-bird seat. There are a couple of things I do to minimize tear-out. 1) Good quality blade designed for plywood. 2) Make the cuts in three passes. I adjust the blade so that the first pass cuts through only the first couple of plys, the second pass goes most the the way through, and the third is adjusted to cut just beyond the bottom ply. 3) I make my cuts on top of some 3/4" or 1" foam insulation. I just set it on the floor and put the workpiece on top of it, so when I make that final pass the piece is fully backed up and supported all the way across the cut.

Charles

That's interesting. One would think you would simply triple your odds of splintering by making three passes as opposed to one.

We always opt for the straight edge, score with razor knife, sharp blade, one pass, technique if we are crosscutting wide panels in the field.

Mark

[Lex Boegen]

I also use a straight-edge guide with a circular saw for all of my initial cuts on plywood. A cheap plywood blade greatly reduces chip-out. I generally cut it about a 1/4 to 3/8" oversize, then rip the final edge on my table saw. I don't have a permanent shop setup, so I have a Bosch 4100 tablesaw that I wheel outside to use. I recently built a pair of platforms from 3/4" plywood to raise up a front-loading washer and dryer. I precut all the pieces with my circular saw, and then trimmed them to final dimensions with the table saw. If you need a perfect cut the first time, you could build a zero-clearance plate for your straightedge from 1/4" hardboard (trim it with the same blade on your circular saw that you'll use for the plywood). Lay the straightedge down with the zero-clearance "insert" on your cut line, and the waste side opposite the zero-clearance insert.

[Charles Wiggins]

That's interesting. One would think you would simply triple your odds of splintering by making three passes as opposed to one.

The trick is the speed and the angle at which the teeth attack the surface of the ply.

It is much easier to keep the RPMs up if you are making a thin cut into the surface as opposed to trying to hog it out in one pass. Plus the teeth are impacting the surface of the wood at a much shallower angle like a planer knife. At this shallow angle the fibers are supported laterally by the fibers next to them, almost like a micro-backer. At the steeper angle the teeth are impacting the surface of the ply in a more vertical motion, and are therefore more likely to lift them (tear out).

However, the whole process is predicated on 1) having a sharp blade, 2) having a guide that does not move, and 3) making sure that the saw stays flat on the guide as you cut each pass.

Charles

[glenn bradley]

A few scraps and a couple clamps.

[Peter Quinn]

Wow, i just did something similar this this weekend! I was scribing some 32X80 doors to old jambs and I had to make a number of cross cuts slightly off square. My cross cut jig is a piece of 1/2" mdf with a piece of 1/4" mdf tacked to it with brads. I use a skill saw with a Freud fine crosscut blade, and it works like a charm. I think the distance between the blade and the edge of the saw plate is 5 1/4"? So I tack the 1/4" guide roughly 6" back from the edge, and leave myself enough room beyond that for some small c clamps. The first pass cuts the leading edge of the jig exactly where the saw blade will land without any measuring AND gives you a ZCI effect, so chip out is between minimal and nonexistent.

It cost roughly $750 less than any commercially available track saw, and while DC is better on most track saws, the quality of cut is not. Short of a bigger fixed machine its the best solution I have found for occasional use.

If I were doing it on the TS with the crosscut sled, I would clamp both pieces together, use an adjustable height saw horse with a good coat of wax as an out rigger either left or right depending on your set up, and cut to a pencil mark. 7' is a fairly random number and should be irrelevant as long as you are close and both pieces are the SAME length. You might even be able to pop a few screws in the two pieces depending on the cabinets design to help hold them together during cutting regardless of the method.

All that being said my RAS has a fine plywood blade on it, a big table and a 24" cross cut, so just bring them over to my house and I'll cut them for you in a jiffy.:rolleyes: