I don't have my horizontal mill online as of yet but find myself in need of making a slot in some tubing. Not wanting to cut the slot in with a torch or plasma and I am allergic to doing it with a right-angle grinder next option was to pair up to saws on an arbor and mill them in with my bench mill only I didn't have a suitable arbor to make 2 parallel cuts a the same time.
Enter a sacrificial 1 inch T50 arbor
cut by a chop saw
Click image for larger version. 

Name:	IMG_20220301_155439ab.jpg 
Views:	106 
Size:	226.7 KB 
ID:	42084
cleaned the end in a lathe
Click image for larger version. 

Name:	IMG_20220301_155926ab.jpg 
Views:	89 
Size:	288.9 KB 
ID:	42085
mounted in a 1" R8 collet
Click image for larger version. 

Name:	IMG_20220301_160657ab.jpg 
Views:	117 
Size:	260.9 KB 
ID:	42086