02-16-2015, 08:31 PM
There's a big difference between a face mill and a shoulder mill. I know, it's semantics to some of you but a night & day difference to someone like me.
I have both. A lead angle face mill can mill flat surfaces but cannot mill to a square shoulder. A 90º shoulder mill can also mill flat surfaces, but can also mill shoulders.
And a fly cutter can be either depending upon how the cutting edge is presented to the workpiece. Do you need one when you have a V555? No, but they can be nice to have when you need one consistent finish across a wide surface. Also, when a fly cutter is used, the larger the sweep is the more variation you get in actual surface finish value. For instance if you have a 5" cutting diameter of the cutter going across a 4.75" wide surface, the measured surface finish at the edges will be 1/2 or less of the reading you would get at the center of the work. And the edges would be "shinier."
The same effect happens with smaller diameter face and shoulder mills, but it seems to be less noticeable. I really noticed it when I was fly-cutting the 6" wide aluminum for my dad's burial urn. The edges polished up with little effort, the center of the plates took 10x longer.
![[Image: IMG_2517-r_zpsb21d2a83.jpg]](http://img.photobucket.com/albums/v466/kenm10759/Dads%20shop/IMG_2517-r_zpsb21d2a83.jpg)
There you have from left to right a face mill, a shoulder mill, a face mill and a face mill.
I have both. A lead angle face mill can mill flat surfaces but cannot mill to a square shoulder. A 90º shoulder mill can also mill flat surfaces, but can also mill shoulders.
And a fly cutter can be either depending upon how the cutting edge is presented to the workpiece. Do you need one when you have a V555? No, but they can be nice to have when you need one consistent finish across a wide surface. Also, when a fly cutter is used, the larger the sweep is the more variation you get in actual surface finish value. For instance if you have a 5" cutting diameter of the cutter going across a 4.75" wide surface, the measured surface finish at the edges will be 1/2 or less of the reading you would get at the center of the work. And the edges would be "shinier."
The same effect happens with smaller diameter face and shoulder mills, but it seems to be less noticeable. I really noticed it when I was fly-cutting the 6" wide aluminum for my dad's burial urn. The edges polished up with little effort, the center of the plates took 10x longer.
There you have from left to right a face mill, a shoulder mill, a face mill and a face mill.