Welding Tips and Tricks

I need to put a 1.5" diameter hole in some 3/16th" sheet steel. I don't have access to a plasma or acetylene torch. I've been told that a bimetal hole saw with lots of oil is my best option. Any other great suggestions here?

Since it's fairly thin, clamp to a sheet of plywood for support when it cuts thru.

A step bit will give you a clean hole. However, at 1-1/2", it will be hard to find and expensive. 1-3/8" is easier to find if you can reduce the diameter a little bit. Buy Milwaukee, Klein or Dewalt. The non-name brands are fairly useless.

You can rent a mag drill and use an annular cutter. Same principle as a hole saw, but it's a beefier setup. Or just take it to a welding shop that has oxy-acetylene, and have them cut the hole for you.

Oscar wrote:You can rent a mag drill and use an annular cutter. Same principle as a hole saw, but it's a beefier setup. Or just take it to a welding shop that has oxy-acetylene, and have them cut the hole for you.

The steel shop thought acetylene might warp it as it's on a relatively narrow piece. That's why they suggested plasma. I'm not sure where I would rent a mag drill and annular cutter. Any suggestions?

A Lenox bi-metal hole saw is the easiest. Drill the 1/4" pilot hole first and then replace the drill in the mandrel with a piece of 1/4 steel rod. Run the drill motor in reverse to score the metal and then forward to drill the hole. By using the rod as the guide instead of the drill, the pilot hold wont get out of round and you'll get a good clean and round hole.

sschefer wrote:A Lenox bi-metal hole saw is the easiest. Drill the 1/4" pilot hole first and then replace the drill in the mandrel with a piece of 1/4 steel rod. Run the drill motor in reverse to score the metal and then forward to drill the hole. By using the rod as the guide instead of the drill, the pilot hold wont get out of round and you'll get a good clean and round hole.

That sounds like a pretty easy option to make work at home without having to go too far out of my way for specialty equipment rental or purchase.

Thanks

Are you hand drilling or drill press. I’ve done a 2” hole in 1/4 plate and the trick is to go slow! Never knew the 1/4 rod as a mandrel but that is sound advice. I’ve had my large holes get up to 1/8 in out of round or more cause it will walk slightly. Oil helps but slow and steady wins the race. I use a Milwaukee super hole hawg. I believe 1st gear is around 400 rpm. With a variable speed trigger and 15amp motor I can do even slower and not stall the motor.

use a hole saw.
other ways is drill a hole big enough to get a jigsaw blade in.
or drill a lot of little holes around the outside and clean up with a file.
all depends on how accurate you need to the hole.

Absolutely, agree with a hole saw. All the better if you have a drill press, but still can do it by hand. I've done a 50mm or bigger one by using CDT cutting fluid spray and a pistol drill.

I hole saw pipe tie ins up to 3inch. After that I get the torch or plasma out. With the hole saw keep the rpm on the drill very slow. You can use water to cool and lube as well.

All solid advice - I often have used hole saws up to 4" on site where I had nothing else - my 2 cents is I do the solid mandrel thing & it works well - if you are free hand drilling rather than pillar drill I would clamp the piece down on something solid like 2" so the mandrel has a good amount of support & add a top piece of ply clamped down -does'nt need to be that thick - hole saw through this first then remove the wooden disc & carry on through the metal using the plywood as radial support so the hole saw does'nt " walk around " - use the lowest speed available & stop often to clear the swarf & apply oil - if you have a pillar drill you can use a " rotabroach " cutter in that as opposed to a mag drill - just needs the morse taper adapter.

Update:
I used a Lenox hole saw. Drilled an 1/8th pilot, then a 1/4" pilot. Given that it was on a large piece and I only have a table top drill press I stuck with my handheld drill. I was trying to fit in a faucet into the hole so a slightly bored out hole that was a little bigger and not totally true was okay. A little extra space would help make sure the threads of the faucet didn't get damaged fitting it into the hole. And the oversized flange hid my sketchy edges with plenty of room to spare.

I went very slow and cleared swarf (love that word) and oiled liberally. 8-10 min later I had the perfect 'imperfect' hole. Thanks for all of the suggestions. And all I had to buy was a $14 hole saw. It probably isn't good for another use, but still cheaper than buying a plasma cutter.

Not that I was close to talking the wife into letting me buy one.

Glad it worked out for you - sometimes less than perfect is good enough using only what you have by & the next time round will seem easier - besides by then you'll have had time to make an excuse to buy a plasma cutter !

I was doing a job recently repairing an outdoor wood stove.
Had to install a new purge air tube on the door. This required a 2 1/2" dia hole in the tube. All I had at the job was my portable welder, 5" angle grinder and my die grinder. I marked my hole with a soap stone, grabbed a 1/8" 6010 electrode, cranked the welder up to 200+ amps and burned the hole out with that. I cleaned up the hole with my die grinder and all was good.
Moral of the story is you use what you have.

Glad it worked out for you - I never tried cutting with 6010 though have often used gouging rods in similar circumstances - as Burt Gummer once said " just doing the best I can with what I got " ( or something like that ! ) - naturally if it was Burt & he only needed a 2-1/2" hole he probably had something that caliber in his truck !

You really smoked his ass.... Doing what I can, with what I got. Tremors 2 is a good movie. Not as good as the first one, but still good.

Thanks Mike - been a while since I watched it - could'nt remember exact quote- now I'm hoping for a thread where we can work in the Dyatlov " 3.6 Roentgens not great - not terrible " quote from Chernobyl ! it's my new favorite !

I haven't been able to watch chernobyl yet.... I'm hearing it's not terrible.

A bit late, but perhaps it will be useful for someone in the future. These hole cutters make clean, straight holes and will cut all but the hardest steel without much problem. I've used them for years, money well spent. Looks like they go up to 1.5"

https://www.blairequipment.com/rotabroach-cutters

They go up to 10-12" plus. All depends on how bug your drill is.

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Dish soap & water in spray bottle makes a good drilling lubricant also. Soap helps lube & the water keeps it cool & it is a HOLE lot easier to clean up! Pun intended.