I am starting a new projected using 3/4" plywood and decided to give my 1/4" compression bit a try.
I was a little hesitant as the cut depth of the bit has to be deep enough to put the compression zone below the surface of the wood. In this case around 8mm. About double with what I normally do with a 1’4 bit.
But with my latest stiffening mods I decided to give it a try, cutting the feed speed in half.
It worked really well, cutting the wood in 3 passes. It really packed the sawdust in tight into the cut. So tight that I was able to not use tabs!
The cut was clean both top and bottom right off of the machine, no sanding
Some of the smaller detail cuts had a bit of chipping on the bottom, But no worse that I have with my downcut bit.
Is the goal to not use tabs, or for a smooth finish? I get great results with a straight 2 flute carbide router bit. I found one with the blades close enough to center that it can plunge.
It was a smooth finish so I didn’t have to do much post carve sanding. Which it did very well.
The discover that with the 3/4 ply I could forgo tables due to the tight packing of sawdust was a added bonus. So no power sanding at all! Just a quick sweep with a sanding sponge) and it is ready to assemble.
With this plywood / bit combination it appears to be consistently repeatable.
It only needs to hold the work piece steady during the very last bit if the final layer of the cut, the rest of the time the remaining material is taking the load. And in this case the sawdust was packed so tight in the cut that I have to pry it free. I could not lift it out by hand.
I have not seen any other bit pack sawdust in tight like that. I assume it is because of the way a compression bit works.