Largest realistic drill size when drilling metal??

[wrdavis]

Depends some on the thickness of the metal. If sheet metal or steel under about 1/8" thick, try a unibit step drill--up to 1" in diameter. But be sure to clamp the metal. Hard to hold by hand from spinning. Harbor Freight sells a set of three for a good price.

[Hobbyman2]

As ya` know here is a lot of heat build up when drilling a hole in metal,,,Remember heat makes things expand and contract,,,,,,,,,bits can get hot and swell ,,,,then they get tight start smoking,,squealing ,binding and even break,,,how would you keep the hole and bit flushed out and cooled ?

In the metal shop ,,,,,,, there was a constant bath of oil cooling the bit flushing out the hole,, same with the pipe thread cutter,,needs a lot of oil,,, its a oily mess ,, not sure why you would want that on the table surface of a wood shop table unless it is a last resort?



I would be sure to clean the table really well and add a new coat of wax when done.



as far as bit size ,,,how big are yo wanting to drill?