If it is only for very occasional use (cutting ally) Just take it very steady and go for it. I sometimes cut ally with my converted pcb machine and I can only use 1/8" shank cutters. I use 1/8" 2flute carbide spiral down cutters as they are the largest cutters I have.
I limit the DOC to 0.5mm, spindle speed about 18k rpm and feed speed about 400mm/min. I use WD40 as cutting fluid applied in small doses so as not to make much mess. After a couple of passes the fluid tends to just stay in the "trench". I do not produce chips as such, more like ally filings which just swim about in the trench. I know that the afficionados will frown upon this method, but it does allow me to cut ally if I wish. G.