Free Metalworking Project Plans: A Fly Cutter
Material: Steel
Units (mm)
Here’s another great weekend project from Ken, a Fly Cutter.
Here’s what Ken has to say about his Fly Cutter plans:
“No, it’s not for cutting up flies, it’s for skimming metal up to say 50mm wide.
This was also designed to screw straight onto my Unimat 3 mill spindle, so again, the rear end was drilled and tapped M14×1 to suit. Make any changes to thread size, to suit your mini mill.
Made of 30mm brt ms x 40mm long, it consists of only three parts, the body and three M6×10 grub screws – couldn’t be simpler. Just add your cutting tool, up to 8mm sq. shank.
Clamping is via two grub screws, and a jacking screw is positioned inside the slot to adjust the angle of the cutting tool.
To be honest, I have not had a lot of success with this cutter, I don’t think my mini mill is strong enough, or I have got something else wrong.
Attached are a couple of pictures, and a pdf drawing. Coming up next is a scissor action knurling tool, and there’s more after that, so stay tuned, the best is yet to come.”
- Ken
Ken originally posted these plans back in 2007 (along with 4 others) on the Metalworking section of Woodworking Australia’s Woodwork Forums. Here’s a link to Ken’s original Fly Cutter post in the Metalworking section of the forum. Check back next Thursday for Ken’s next project, a Scissor Action Knurling Tool.
Thanks for contributing Ken! If anyone has advise for Ken on why he’s not having the best of luck with his Fly Cutter, please leave a comment.
FLYCUTTER.pdf (41.6 KiB, 1,492 hits)
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Tags: Intermediate, Lathe, Units (mm)
March 24th, 2009 at 10:50 AM
Hi
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)
March 24th, 2009 at 3:11 PM
Thanks for the tips Jaakko!
March 25th, 2009 at 8:53 AM
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.
March 25th, 2009 at 11:25 AM
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.
March 25th, 2009 at 11:28 AM
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.