found a good bit for stainless drilling

[GranillaNutz]

one of my stops this morning at the local new orleans electrical supply houses, NuLite, i noticed these new drill bits they had in. retail for the set i think was 120, but they had a sale for 80 bux for the set.
IDEAL INDUSTRIES, INC. - TKO™ Carbide Tipped Hole Cutter Kit
it claims 1000 cuts thru stainless and 2000 thru sheetmetal. i tried it on my keg and it went thru a WHOLE lot better than my 80 dollar greenlee unibit. although i didn't have the size control of the hole that i get with my unibit, it really did the job well for my heating element hole. with my unibit, i was able to pretty much thread the element in there. with the hole saw, the element slid in, but with minimal play around the threads and still a snug fit.

 

[Aleforge]

Did you use cutting oil by chance? I am guessing you did, but some guys forget to do that and it makes cutting stainless a whole lot easier as well as extends the life of your cutters.

 

[GranillaNutz]

yes i did use cutting oil... with both bits. i have made the mistake of cutting stainless with a normal bimetal hole saw at the full rpm of my drill and no oil when i first started doing construction... it ended up looking like one of our local crackheads.. no teef

 

[AnOldUR]

yes i did use cutting oil... with both bits.

You don't always need cutting oils with carbide. Carbide is sensitive to thermal shock making chipping a greater risk than wear in this application. If you could keep a constant flow of fluid to the cutting surface you’d be OK, but that is not practical so I’d run it dry. The one thing to keep in mind is that the pilot drill is high speed steel which does need oil.

Note that in stainless, for a 7/8” hole your speed should be 500-600 rpm with carbide as compared to around 130 for the same size tool made of high speed steel.