Comments on: Free Metalworking Project Plans: A Fly Cutter

By: Jaakko Fagerlund

Jaakko Fagerlund — Wed, 25 Mar 2009 18:28:59 +0000

Good example of the tool slots position: http://www.aoou85.dsl.pipex.com/horizontal%20fly%20cutter1.jpg

I think that is the authors main problem.

By: Jaakko Fagerlund

Jaakko Fagerlund — Wed, 25 Mar 2009 18:25:58 +0000

And still one, quite important detail: The fly cutters tool slot should be positioned so that when you insert a tool, the tools cutting edge is in line with the center of the fly cutter.

Otherwise the cutting angles are changed dramatically (think of a boring bar too low or too high) and it will produce bad quality or will not cut at all.

By: Jaakko Fagerlund

Jaakko Fagerlund — Wed, 25 Mar 2009 15:53:35 +0000

Oh and forgot one thing: That number 6000 is for HSS tool bits. For carbide you can multiply by 6, so the constant is 36.000.

By: admin

admin — Tue, 24 Mar 2009 22:11:37 +0000

Thanks for the tips Jaakko!

By: Jaakko Fagerlund

Jaakko Fagerlund — Tue, 24 Mar 2009 17:50:27 +0000

I think problems are these (most common first):

1. Mill has not enough power (decrease cutting radius and depth of cut)
2. Tool bit is not shaped correctly (use a regular left handed lathe tool bit with a rounded nose)
3. Too much rpm’s (tip: 6000 / diameter_mm = RPM)
4. Too much feed (tip: 0.1 x 1 x RPM = feedrate mm/min)
5. Too small tool bit shank (deflects because of cutting forces)