flycutters

[Chuck in E. TN]

Hi Folks,
I’m requesting a little guidance/discussion on my next project for my mill tooling. I want to make a fly cutter. I have a nice set of plans printed from the web. The designer made his just under 1” in diameter at the head, with a 3/8” dia. shank. The head was angled at 20°, and was milled to accept a ¼” tool bit.
Aside from the obvious, bigger may be better, what are the advantages/disadvantages/recommendations for diameter of the head, angle of the head, and size of tool bit.it can hold? Any guidance for relating the dimentions of the flycutter to the size of the workpiece that can be handled? I have no formal training in running a mill or designing tooling.  I have a feeling I’m going to be making several sizes.
The general plan I’m going by is here:
http://www.deansphotographica.com/machining/projects/mill/flycutter/flycutter.html
Thanks for any and all input.

Chuck in E. TN

[kvom]

I think it will depend on the size of your mill and lathe and what material you have.  I made mine for a Bridgeport mill with a 3/4" shank and 3/8" tool from 2" diameter steel.  It can machine up to a 5" wide workpiece.

[Chuck in E. TN]

I have an X2 from Harbor Freight. I work in aluminum and steel.

Chuck in E. TN

[Dean W]

Hi Chuck;
I think your milling machine is a bit bigger than mine.  The one I made, (in the link) is for a machine that only weighs about 75 pounds.  If I'm looking at the right mini mill, it looks like yours weighs quite a bit more than that, so you might up the size a bit.  Seems 1 1/2" dia would be reasonable.

Probably the best thing I can suggest is to use the fly cutter in a proper collet or end mill holder.  It would be hard on a drill chuck, and might shake things loose.  The largest practical shank diameter is what I would go for, and the shank short enough that it doesn't stick out of the spindle very far.

Dean