Infinity Tools 1/2"シャンク ホゾ穴・ホゾ用ルータービット

Finally, a bit that leaves tenon shoulders crisp enough that I hardly need any sanding before glue-up. The downshear geometry really does keep the cut fray-free, even in plywood where I usually fight tear-out.

Took a solid chunk of white oak through the bit and the tenon shoulders came out dead flat—no chipping on the edges at all. The downshear cut left a surface so smooth I barely needed to sand before glue-up. Exactly what I hoped for in a mortise bit.

Finally got clean tenon shoulders on some hard maple without any chip-out—the downshear geometry really does what it promises. These bits also leave a surprisingly flat bottom, which saves me cleanup time on every joint.