Milling a radius

[mfarris]

Very much a newb here, and was wondering how you go about milling a smooth radius, such as the front bearing housing on the Whittle V8 in the second post of this thread:

http://www.homemodelenginemachinist.com/f31/whittle-aero-v8-wip-4583/index45.html

Looks like he's using a rotary table and perhaps a ball endmill, but was just looking for a few more details on how the poster milled this circurlar nose to such a smooth finish.

 

[Jasonb]

The trumpet shape has been formed in the lathe with the part held off centre in a 4-jaw chuck. The curve can be freehanded or done with a ball cutter set to cut convex like this

The set up shown on the mill is to shape the bolting flange to shape, no to do the trumpet shape and is just done with a straight cutter.

J

 

[Bovine]

I needed to make a 1/4" radius on a flycutter for a class project and I decided to grind the radius on a 1/2" piece of HSS. To prevent chatter, I used the compound set at a steep angle to advance the cutter. Shaving were thin and chatter minimal.