Cutting Plywood

[jaco]

This is a tip from the latest E-news letter by PlansNOW
(apologies for the loss of the illustrations!)

Cleaner Plywood Cuts
The height of your saw blade can make a big difference in how much splintering you'll run into while cutting plywood. If the blade is set too high (see top illustration), the teeth are cutting almost perpendicular to the veneer layers in the wood. This might give you a clean cut on top, but you'll likely see some chipout on the underside of the panel.

One way to avoid this kind of splintering with plywood is to lower the height of your blade. Set your adjustment so the blade height is only 1/8" above the plywood (bottom image). This changes the angle at which the cutting teeth bite into the plywood, and significantly reduces the amount of chipout you'll see on the underside of your plywood panel.

[Scrit]

There is also something to be said for moving to a blade specifically designed to cut plywood, i.e. an ATB (alternative top bevel) blade with a rake angle of 10° to 15° (e.g Freud LU2A and LU2B types), but don't go for too many teeth - on a 10in saw a 60 tooth blade is enough whilst for 12in saws a 72 tooth blade is often chosen. I've also had good results with slightly negative rake blades akin to those used in mitre and radial arm saws, but beware the incrteased tendency to catch and kickback when using this type of blade on a table saw. For plywood I, too, normally set the blade to be no more than gullet height above the material although it can take a bit of fiddling with test cuts to find the "sweet spot" at which the cut is best.

Scrit