I need to do some remodeling in a commercial kitchen that involves drilling a lot of holes in stainless steel. I never realized the stuff is so hard to drill or so tough on drills. What drill speed should I be using and how much feed pressure is best? TIA Clint
Speed should be relatively slow. What size of drill? What thickness of metal? Pressure should be high. The worst thing you can do with stainless is to let the bit skid, without cutting. This work-hardens the stainless, and makes it almost impossible to cut. A coolant, such as vegetable oil is a good idea.
Mostly clearance and pilot holes for sheet metal screws in ,yep, sheet metal.
Don't center punch the location. This work hardens the exact point you want to drill. Use a center drill to start the hole. Unibits are great for sheet metal, they make a nice round hole not the 3 lobed hole that is often made in sheet metal. Use coolant.
Buy a bunch of cobalt drill bits the right diameter. Cobalt bits that small only cost about a $1 each >
I buy bags of 10.
If the bits have ground spit tips then center punching is unnecessary.
Stay under 50 surface feet per minute and use very high drill pressure and you will have complete succcess. Leigh@MarMachine
And get some MolyDee. If you can clamp a piece of mild steel behind the work you'll not chip the drills as readily.
michael
Odds are some or most of the holes will be near the edge of the sheetmetal. In this case I've found using a punch (I use a whitney style) will give some good results aswell. No distortion from the high drill pressure, no scratches from the chips, easy to line up the hole (no walking drill bits), plus the die's last quite a while even in stainless. Just a lil advice, but some cases a drill is your only option.
If you need to centre punch to get good hole location grind your punch to a three sided pyramid tip. The triangular indent gives the drilltip something to bite on to cut through the work hardened layer.
Sorta off topic to the OP's question but one demo I did quite amazed me. I wanted to demo burning out a bit with too much speed. Bought some standard 1/4" jobber bits from MSC, set the Bridgport at 2000 (!!) rpm, plunged it hard into a 1" block of
303 sta> I need to do some remodeling in a commercial kitchen that involves drilling a
I will have to try this. Not being able to locate with scribed lines and a center punch is a PITA. No problems with the three lobed hole? Kent
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