Cutting plywood - nice sharp edges?

Evening all...
Anyone got any hints on cutting plywood with nice clean, sharp, straight edges on both sides? The best I've managed so far is to cut it to within a few mm of the line with a jigsaw, then use the router against a clamped straightedge. Good results, but very time-consuming!
TIA Andrew
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On Sun, 02 Nov 2003 19:28:47 +0000, Andrew J Instone-Cowie

A very fine plywood blade (lots of teeth) and scoring the surfaces, or a table saw with scoring blade.
.andy
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On Sun, 02 Nov 2003 19:28:47 +0000, Andrew J Instone-Cowie

Get a sharp knife, like a marking knife (Axminster's Japanese ones, for around a fiver) and score along the edges of the saw kerf before cutting. Maybe score a little wider than this, if you can't guarantee accuracy.
Use the right sawblade. Circular saws are supplied with combi blades that are intended to crosscut 2x4s and even do some light ripping. If all you ever use your handheld saw for are the initial cuts on a big sheet of plywood or MDF, then it's worth getting a more appropriate blade. It's especially useful on a Lucky Golden Hedgehog brand saw from Happy Shopper.
Use birch plywood. Doesn't solve it, but the fibres are a lot less brittle than rainforest plywood. You'll still have tears, but they're less than 1/4" long. Give it a try, whenever you need some "nice" plywood. http://codesmiths.com/shed/furniture/gothic_chair.htm
Do it on a table saw with a scoring blade.
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Andy Dingley wrote:

Another trick not mentioned is to cut oversize and run a router along the edge against a straight edge.
With a sharp curtter this can priduce a very clean edge indeed.
Its quite a faff tho getting the straight edge in place, and supporting the router (or workpiece if you use a table router).
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On Mon, 03 Nov 2003 08:57:28 +0000, The Natural Philosopher wrote:

Except it was mentioned by the OP.....
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Make up one of these...
http://members.aol.com/woodmiser1/sawbd.htm
Clamp it into position, then run down the straight edge with a sharp, sturdy knife to sever the surface fibres.
Then cut with the circular saw.
Has been working with me when slicing up veneered MDF this summer.
cheers Richard
-- Richard Sampson
email me at richard at olifant d-ot co do-t uk
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With a jigsaw it's best to use the special blades made for the job. These have teeth like a miniature pruning saw - the teeth are not set but are all internal to the blade and are shaped with a sharp edge for both the pull and push cut. They are sold under a variety of names "cabinet", "extra fine cut" and a couple of others I can't recall at present. You can tell which they are by looking at the blade itself. If the teeth do not protrude left/right from the blade then you have the right one.
Another approach is to clamp the edge to be cut with scrap ply top and bottom and cut through the lot. Nice edge, but very wasteful on wood.
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Try scoring the ply with a modelling knife first then cut with a good hard point hand saw. I personally only use a fine toothed wood or hacksaw jigsaw blade to cut shapes in plywood and any straight cuts are done with a hand saw.
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