"Those bits are at least 8-10 years old. I’m sure they are just fine. Our etching has been highly upgraded since those were produced.
I’ve attached our catalog which has the 1300 series down cuts on page 20. I think these are part #1320, or 1325. I hope this is helpful."
Communication from Vortex
Dimensions match 1325
Series 1300
TWO FLUTE DOWNCUT FINISHING SPIRALS
Downcut tools are used when the down shearing effect of the tool is preferred. This tool will produce a clean top edge of a dado type or groove type cut or simply a thru cut where the bottom edge quality is
not important. These tools will direct chip flow downward while helping hold parts onto the table or pod. When nest cutting the tool path remains packed with chips which helps preserve maximum vacuum. Never plunge straight down with downcut tooling as this may cause fire or breakage.