Having experience in safe penetration, I can tell you that you will need a hammer drill, a 1/2" good quality hammer drill and a lot of drill bits. "Soft" hard plate can be penetrated with standard HSS bits but they need to be very sharp and with a shallow attack...You'll need to know how to sharpen them to achieve a hole. Safe bits are expensive and no better than re-shaped masonry drill bits. Again you need to know how to grind a proper rake angle and you need a special expensive stone to work tungsten carbide. A drill rig is almost necessary to drill "real" hard plate or chromium but a tie-down strap with a ratchet, wrapped around the safe and the drill will do...So will a chain and a 2x4... Drill speed AND torque are important here. I burned out many drills, even good ones will get uncomfortably hot in your hands...
Don't forget, you'll need a lot of drill bits...The average safe I work on uses 3-6 bits...On ONE hole...Some hard plate will need more...I have hit "ball bearing" packs that took more than 30 bits to get through...
You'll need a stool to sit on, magnifiying glass, various strong magnets, long punches, long wires, lubricants, protractor, graph paper,sometimes a calculator, pencil, ruler, large hammer, emergency dials, dial puller....A means to make "special" tools" ...
My bore scope needs a 17/32' hole for a strait entry, but I found that with the mirror or at an angle, weather it be to avoid hard plate or glass re-locker, a 3/8" hole allows enough room to wiggle and flex the camera wand into place...
Between the 4 of us at our shop, we have 140 years experience ...And records as far as the 1850...
...And still, we get some safes that none of has ever seen...Experience, common sense and intuition prevails...
That is not including the mal-functions...
M.