I use them to cut round holes in 3/8" Baltic Birch plywood with a Ridgid compact router and a Rockler circular die Surprisingly, I can cut a circle in one pass - at the full 3/8" depth and at the highest RPM - without the cutter getting stuck. When the cut is complete, the bit is still cold to the touch. The edge quality is great very good , little to no sharpening required - see photo In fact it gives me better quality than the Whiteside spiral chisel I also own: the up cut chisel gives someβ¦