Had to drill some 1" holes in 1/2" plate today,....several of them... punched them and moved to the drill press.
started with a 3/8 bit then up to 3/4 then up to 1". Lots of oil and slow speed and it worked fine... just took a while

While I was bored (pun intended) I was wondering if there was a recognized increment you should use when stepping up through bit sizes..?? every 1/4" ? every 1/8"? none of my stuff is exotic or hardened just plain old cold rolled or hot rolled plate usually ... or angle iron... The step drill you can buy do great on thin stuff but when you get to a 1/2 or above it really isn't the thing to use.... ideas ??

john

 

On a 1" hole I usually go, 1/4, 1/2, 3/4, than 1" final, but most any combination will work. Just bored a couple plates for my tow truck. 1" holes in 1 1/2' plate. Fun..........lol

 

I do like Don does
Step bits work well on sheet metal, not so much for plate

 

1" holes in 1/2" plate?
Plasma torch, 5 seconds a piece...............I know it's cheating.

 

Drilling in wood is so much easier...lol

 

Depending on material. Broach bits. Shorttend a freightliner a few years ago. Rented a magnetic drill press. Worked great! Bits were about a hundred dollars though. .....

 

Don't think there's any set "step" you're suppose to use. Just keep going bigger. High quality drill bits and plenty of oil.

I agree in using a torch or plasma cutter when you can get away with it!

 

john... please send broach bits or a hundred dollars ... thanks
john

 

we have "hole jigs" at the plant, made in a sheet of UHMW plastic that are much bigger than the actual size hole you need but fit the end of the plasma torch so you have a guide and make perfect holes everytime using the hand-held plasma................It really is cheating.

 

I've got a plasma cutter... it's an OLDER model and 1/4-3/8 is it's limit on 'clean' cut... 1/2 is a rough cut, like a bad torch cut...these needed to be clean and round for a smooth fit for a pin... so I drilled... it was quicker than plasma and die grinder to smooth.

 

I know it's a lot easier on a hand drill if you do work your way up in size, and easier on you as well...lol

 

it's still a bone breaker when you get up around 3/4. I've got a Milwaukee 1/2 corded... was drilling some 3/4 in a frame rail and that devil hung. nearly broke my wrist. Also many drill makers put the trigger lock on the left side so you can set it with a finger on your right hand... We left handed folks can get messed up as we tend to push it down gripping the drill...then you can't let go when the drill hangs and starts trying to slam you around the room like a wrestler in a cartoon.

 

I try not to push on the drill but let ease its way through if I can..

 

You could tape a nut over the lock button John so it don't get depressed..

 

Sorry, cheating again.................we have a brand new ESAB state of the art hand plasma, it will make "drill" smooth holes in 1" plate if you use a jig for the holes.
Only thing that's dicey is holding it perfectly still during the volcano that erupts when it pierces the plate.