Well it does say it is for plastic and wood,but if you take it easy i bet you can do soft aluminum without a hitch.Last night i was milling a Ryobi case on my drill press,had a round stone in it.Was holding the case with a deathgrip...KERPWOIE KIDS!!The case got flung ten feet accross the room.Hurried up to see if i still had all my fingers,LMAO!Yeppers,still all there,went right back to milling,hehe!! I will post some pictures of these engines when i get some done.Going the 'EXTREME' route on them all if i can afford it.I am doing some DEAD SERIOUS GRINDING!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!hehe!