3 flute end mill 3 flute end mill for aluminum 3 flute carbide end mill gemeinhardt 3sb flute gemeinhardt flute 3shb 3/8-16 spiral flute tap 1/2 carbide end mill 3 flute 3/4 carbide end mill 4 flute 3/8 4 flute carbide end mill gemeinhardt solid silver flute m3s