To cut a 9" x 8" ply piece diagonally

[radhak]

I was trying to cut a piece of plywood sized 9 by 8 inches diagonally into 2, and realized that i did not know how to do it on the TS. The stock miter guage does not allow me the appropriate angle, and the fence does not help.

Tried with the circular saw, but could not get to clamp a straight-edge-guide to the workpiece : the clamps got in the way of the CS (it being a small piece of wood). Ended up using the Jigsaw freehand, and did not like the end results : not sharp enough, not straight enough.

So what is the best way to cut this?

[greencat]

Far from an expert but I have seen jigs that would ride against the rip fence. The jig would be a piece that has a triangle cutout for your piece to ride in. You could also make a jig for the cs to allow you to clamp down. Depends how important the piece is.

[LCHIEN]

A simple way to do this would be to have a simple jig, 6-10" wide x 2' long piece of plywood, squared up.
Place the 2' edge along the rip fence. Place the rip fence so the opposite edge rides right up to the blade (call this the cut-edge).
Screw, glue or double-stick tape the 8"x9" piece to the jig so that two opposite corners of the workpiece lie along the cut-edge of the jig.
Now with the 2' edge along the rip fence, push the jig forward and the workpiece will be cut along the diagonal less the kerf. If you want the two pieces identical, you will need to hang the workpiece out from the jig by an additional half a kerf.

[bigsteel15]

The stock miter guage does not allow me the appropriate angle

The angle required is ~42.6 degrees so you could safely set it at 42-1/2 and get it to work.

[dkhoward]

I use my radial arm saw . . . .

[wardprobst]

Some good replies, especially Mr. Chien. I would use a Ryoba (Japanese pull saw) personally. Scribe the line, the hardest part will be to start the cut- use a sharp knife blade to cut the point for a place to start.
DP

[Tequila]

Some good replies, especially Mr. Chien. I would use a Ryoba (Japanese pull saw) personally. Scribe the line, the hardest part will be to start the cut- use a sharp knife blade to cut the point for a place to start.
DP

Crazy suggestion, but that's exactly what I'd do. Some jobs are just easier and safer with hand tools.

[cabinetman]

I use the same type of jig Loring suggested. Mine was cut from a 10' sheet of plywood that I also use in the same manner as described, but also use it for straightedging. The difference in straightedging is that you don't consider the "cut" edge of the jig, only that you have a straight edge piece following the fence. For long lumber, I just use finish nails to hold the jig. Works great.



"I'M NEVER WRONG - BUT I'M NOT ALWAYS RIGHT"

[radhak]

thanks everybody.
Brian, i went back and checked - the angle is possible, but holding the miter-guage steady extended in front of the saw before starting the cut, and holding the piece at that angle without fear of it slipping, is all too much for me. I am guessing a sliding-crosscut-sled might be the answer?

And the various jigs suggested seem interesting enough for me to ponder over.

With about a dozen such pieces to be cut, handsawing them is not something i'd look forward to - past attempts have resulted in steady-as-jelly line-of-cut

[spratone]

I have used the SMT on my BT3. Just adjust the angle, clamp a stop block and cut the angle. Worked well. Only problem I had was the size of the board (16" square). I had to remove a few parts from the miter fence to allow it to go back far enough on the SMT, then tightened the heck out of the knob. I would like to mod the SMT for larger pieces.

[LCHIEN]

thanks everybody.
Brian, i went back and checked - the angle is possible, but holding the miter-guage steady extended in front of the saw before starting the cut, and holding the piece at that angle without fear of it slipping, is all too much for me. I am guessing a sliding-crosscut-sled might be the answer?

And the various jigs suggested seem interesting enough for me to ponder over.

With about a dozen such pieces to be cut, handsawing them is not something i'd look forward to - past attempts have resulted in steady-as-jelly line-of-cut

If I had a dozen to cut, I would do my jig I described above, adding this:

Use two pieces of 1x2 to outline the edge or act as stops on the jig for the position of the workpiece so I wouldn't have to carefully position it each time. I would also use a pair of toggle clamps mounted to the 1x2 to hold it in place while sawing rather than use tape or temporary nails. I might add a simple vertical handle to the jig to use to help me push it forward and keep it against the fence safely. Just a 6" piece of 1" dowel mounted near the intersection of the two 1x2s.

Jig toggle clamp:


http://www.rockler.com/product.cfm?O...Select=Details

like #20731. available lots of other places. I keep a few on hand for temporary jigs.

It'll save time and make your work accurate.
After you're done reclaim the clamps and toss the jig.