Rack involute fly cutter - video

**Jon** · Mar 24, 2022, 03:00 PM

Rack involute fly cutter. By Clickspring. 3:12 video:

**tonyfoale** · Mar 24, 2022, 06:01 PM

A rack like any other gear or pinion should have an involute shape but that shape is straight sided for a rack. So the video title is misleading. The fly cutter was sharpened to have flat sides and of course it cut flat sides on the rack.

**Hans Pearson** · Mar 25, 2022, 09:34 AM

The title is misleading, but a rack does have straight teeth. The way a gear exits a rack is slightly different to the way two gears part. I unwittlingly cut a rack with an involute cutter, and I promise you, it does not work well.

**tonyfoale** · Mar 25, 2022, 01:27 PM

Originally Posted by Hans Pearson

The title is misleading, but a rack does have straight teeth. The way a gear exits a rack is slightly different to the way two gears part. I unwittlingly cut a rack with an involute cutter, and I promise you, it does not work well.

A rack is just a gear with infinite radius. The same rules apply. It requires an involute shape like any gear, it is just that the involute surface is straight in this case.