vhf Burs

Burs break often

I have VHF E4 milling machine for milling GC Lisi only. The burs mill the crowns great when they do work. However, they need to be replaced often and sometimes way before it says it needs to be replaced (I know it is GC Lisi, but way quicker than I though). Sometimes the burs break at the first time using them. It’s gut wrenching when the burs are at least $40 each to replace.