[kNucklBustr]

Besides Onsrud 1 flute bit, what is a second alternative end mill to use cutting UHMW ?

Using 1/16 - 5/16" dia end mill. (Onsrud 5/16 is $60, not going there)

Ive tried a HSS 3/8 2F CC end mill at F8, spindle at 1750 w/ decent results.
However, the walls of a 1/2" deep slot have these tiny vertical uniform lines.

Used UHMW on a lathe and know how this stuff can get real smooth.

Pic of mill cut