--Soluble oil is great stuff but you might want to set it up in a spray mist unit if you're able to do the job on a mill or drillpress so you've always got coverage. Hot rolled is nasty stuff at least until you break thru the 'crust' so go slow when you start the holes. One brand you might want to try is Westlube. I use it straight for stainless and titanium but you could probably thin it a bit on hot rolled to make it go a little further.