Quote Originally Posted by cropwell View Post
For Ali I use half the cutter diameter as the DOC, but I use Open Architecture cutters like these https://www.sorotec.de/shop/Cutting-...s/2-Flute-ALU/ Spindle is 12000 rpm and feed is 5mm/sec. It seems slow, but maybe I am just cautious. Most of what I do is one off. Lots of air to clear chips, and my coolant is WD40 and this gives OK results on that soft sheet ali 1050 grade.

But it did take a few broken cutters to get there.
Your very brave man cutting 1050 with those settings as your doing a lot of rubbing rather than cutting.!
12K is far too slow for 1mm cutter, to be honest so is 24K, should be more like 40-50K. Also, the 50% Diameter rule doesn't often work out too well for sub 1mm cutters. For small cutters below 3mm, I wouldn't go much more than 30% and down to 10% for sub 1mm.