Rigidity is your friend,make sure your set-up is solid as it can be.
I have had good luck drilling harden tool steel (52-54 rc) with these. They fairly cheaper than solid carbide.
http://www.mcmaster.com/#carbide-tipped-drill-bits/=zz7mvt
Zmotor........Nice,I'm stealing that one. I have been using indicols for 20years now. I use different length rods to get out on bigger mold bases. It gets a little shaky on that .250 rod.
I have one....its a great grill/mediocre smoker. It has to many air leaks in the firebox/damper. they can be modded to work much better. Its no BGE,but for the money I am happy with it.
I like it.......I was thinking those fake stamped tin celling tiles would look cool,but I need to finish the backslash in my kitchen with them 1st before think about doing the shop.