Cutting vs Tearing Plywood

[James M]

I recently cut about 3 sheets of cabinet grade plywood. I noticed that the cuts did not appear to be clean. By that I mean I ran my finger along the cut part and it appeared that some of the layers "dislodged" and provided a bumpy surface.

With a cabinet grade plywood do botters run a final pass to get a cleaner cut?


James

[Ajcoholic]

I recently cut about 3 sheets of cabinet grade plywood. I noticed that the cuts did not appear to be clean. By that I mean I ran my finger along the cut part and it appeared that some of the layers "dislodged" and provided a bumpy surface.

With a cabinet grade plywood do botters run a final pass to get a cleaner cut?


James

I have always cut two passes (whether for plywood, or other cores) with the first being nearly full depth climb cutting, and a final pass fully through conventionally cutting.

For example, if I'm cutting 3/4"plywood I will climb cut the first pass at .68", then cut through at .755" conventionally.

Some very hard plywoods (like Baltic Birch) can feel a bit rough if you cut too fast - I think the alternate grains get pressed down a bit and compress and spring back so the end grain layer feels proud of the layers with grain parallel to the cut edge.

Sharp bit and find the feed speed that leaves the best cut. I find for me, 360 inch per minute to 420 ( 3 to 4 inches per second) seems to give a good cut edge with rpm depending upon what diameter cutter Im using.

[dlcw]

Also, if you are using a plywood with voids (most plywoods) you will get those little chunks of veneer that bust out. It has to do with the quality of the material you are cutting (which is getting worse and worse). One type that will tend to chip a little less is Armorcore plywood. This has 1/8" thick MDF right under the outer veneer, on both sides of the plywood. The MDF tends to make the veneer surface smoother and more uniform in thickness throughout because they sand the MDF before putting the outside veneer on. For my 3/4" plywood, I use Armorcore exclusively. More expensive, but much higher quality than veneer core.

[James M]

Thank you all for your suggestions. I'll try some of Andrew's techniques before bucking up for more expensive material.

James