For sale is 1 pc of this USA Made 5/8" Solid Carbide End Mill, 1 5/8 flute length, center cutting, 3.5" OAL, TICN Coated 45 DEG HELIX NIAGARA # 61475 # W80842-1 MSC sells similar ones BUT with A 42 DEGREE helix, but ONLY 1.25" flute length, but made in Korea, for 176.00 ea,! and this is MUCH better,  and USA made!
 
Use the MSC# 81691990 one below JUST to compare; Mine that is for sale here has a 45 degree helix, and has 1.625" flute length, and USA MADE!  NOT like the comparison below, please see the pics as to what you get for lengths. 

Square End Mill: 2 Flute, Solid Carbide