What kind and brand of hole saw is best for cutting a 3 inch diameter hole in a 1/8 inch thick hollow steel post?
Thanks in advance
One hole in 1/8 inch steel should not be a problem for any hole saw. I would go with a bi-metal saw such as Lenox. A carbide tipped hole saw will last much longer, but for occasional use the bi-metal will be fine.
I have some other questions. Do I need to use a cutting oil or lubricant? Where do I buy it and how do I use it?
Lubrication will keep the cutting tool cooler and help clear the chips, which will allow you to cut faster and make the saw last longer. There are special lubricants that you can purchase from sources such as MSC and ENCO. You can also just use any oil you have around. The best approach is to continuously flood the work with lubricating fluid. HOWEVER, for one hole in 1/8 inch steel I would not worry about lubricating the saw. Just don't run the saw too fast or feed it too fast.
Carbide tipped...and YES!!...the lube is a must
Cuts faster, cleaner and cooler...Rapid tap is a common brand
A variable speed drill would help, you want to cut SLOW
Drilling or cutting works best a slower speeds
We got the holes cut today and your suggestions helped a lot!