Spindle speed Bridgeport

[Mutt]

Hey y'all. Here's the situation. I have a gray iron casting tube that is about 1¼" diameter , 4" long, about 3/16"wall thickness. On one side of it, running along the length of it, is a 3/8" slot about 2" long. I to bevel/radius this slot from end to end.
I bought a new 1/2" 4 flute solid carbide end mill that is nice and sharp.
from this This one is just black pipe for the reference

to this



I need to know what spindle speed (on my step pulley Bridgeport), to run, to make the best looking cut. I don't understand how anyone can figure out SFM with these new power feed units ??? so I'll have to wing that.
Thanks

Mutt

 

[4ssss]

That bevel could be done easier on the cast iron with a ball mill. I'd run the BP fairly slow, but not in back gear. The other bevel is done while the tubing is being pierced on a press

 

[Mutt]

Thanks.I used the ball mill I spoke of in the OP. Came out fine at 660rpm