Another flycutter build question holding & angle

[umahunter]

Ok I'm going to build a flycutter with a 3/4 shank and I'm trying to figure what's the best way to hold it in the mill to mill the angled slot. just stick it in the vise like anything else as low as possible only contacting to small surfaces or should I clamp it in a 5c collet block which would stick up higher but be held in a collet . question number 2 I'm building it to use a 1/4 inch left hand indexable bit the triangle style harborfreight sells for thier mini lathe. from what ive gathered I plan to cut the slot at at 20 degree angle does that seem right to those in the know thanks for your help

 

[T Bredehoft]

The angle of attack of the cutting edge is what is important. Imagine a lathe tool cutting a bar of steel, what does the cutting tool look like, Well, make your fly cutter the same relative to the uncut surface. It should cut first at the surface with the tip following behind at maybe 30 degrees.

 

[brino]

whenever I need to hold a round shank in the mill vise, I like to use a v-block on one side.
-brino