Straighten plywood edges

[mike]

I am a beginner woodworker and I am looking to make a rip jig for circular saw. I have a scrap piece of ply with both long edges crooked. Any ideas to get straight edges? I was thinking of attaching straight 1x3 to ply edges, with 1x3 running along Tablesaw arm. Hopefully this would create new straight edges.

Any other suggestions?

[Ken Kortch]

Or buy one of these systems and be done with it. I've used it for quite a few years. They are fantastic for cutting down plywood.

http://www.amazon.com/Tracksaw-System-108-SMARTBASE-eurekazone/dp/B...

[Ken Darga]

This is one system I use, that is very handy, and incorporates many useful features.

http://www.rockler.com/product.cfm?page=25384

52-104'' low prfile straight edge

  

sections join together with bars

t-square

acrylic base and track guide for router or circular saw

  

Makes for effective shop use and on the job site.

Works for me.

[John Porter]

1x3s are seldom straight. As has already been noted, being wider helps and ply or composite is more stable. Take a look at the 1x12 ply in a box store and you will see how badly timber can distort.

Metal is more reliable, a 4' straight edge. HD SKU 395870 is less than $10 and you can drill holes to screw it into the ply, or if you want to protect the ply, use clamps

For twice that you can get SKU # 714910 to cut 8', same technique.

You can a 4' clamp straight edge which is very useful for cutting sheet goods for <$40 - does not have a SKU, it is HD #540950.

If you want to square the ply use the Pythagorus 345 principle to align your cuts off the first one. 4x along straight edge, 3x along the right angle and when the distance between the far points is 5x, you have a square edge on the 3x side.