Drilling a big hole in small steel plate

For my rotary phase converter, I want to install an electrical box to take in incoming electrical wire and to install two pushbutton switches on it.

Just a little more detail. The electrical box from home depot will be mounted on outside. I will punch out a hole in the side for incoming electcical cable that will then go into the back of the box iinto the inside of my RPC.

The electrical box will be covered by a solid, "blind" standard cover. I will drill two 1/2" holes in the cover to accommodate my pushbutton switches that I salvaged from some equipment earlier. One switch (NO) will be the start switch and the NC switch will be the stop switch.

The issue is, how do I drill big holes in small plate. I cannot simply fixate it in my vise, because it would bend. I cannot drill 1/2" holes and hold the plate with pliers, I know that it is unsafe. Help me resolve this quandary. I have a regular floor drill press.

Maybe I will drill a small hole with my DP, holding the cover with pliers, and then would mount the plate in my bench vise and use a hand drill.

i
Reply to
Ignoramus27279
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It's actually possible in the vise (I did it the other day) but it does take some feel.

Two other options. Mount the cover on the box and then clamp the box in the vise. Or get a piece of wood and use a C-clamp to clamp the cover to the table of the drill press with the wood between the table and the cover.

Reply to
Wayne Cook

I would probably put a piece of scrap wood in the vise that is slightly larger than the plate and low enough in the vise so the plate will not turn when placed on top of the wood. Some chance that the plate will be sucked up the drill when it breaks through so watch the fingers.

Dan

Ignoramus27279 wrote:

Reply to
dcaster

Use a c big c clamp and clamp it to the drill prtess table. Then use a "Bullet" drill to put in the hole. Run the drill slowly. Or, step on the thing while it's on the floor and use the "bullet" drill to drill the hole. I just checked on the web. Black and Decker still make Bullet drills and they can be purchased at ACE Hardware. You will not need a pilot drill hole when using a bullet drill. ERS

Reply to
Eric R Snow

This is typically done with greenlee chassis punches.

Jim

Reply to
jim rozen

thanks, I will use wood and some clamps also...

i

Reply to
Ignoramus27279

simply

Like someone suggested, mount the plate on a steel handybox and clamp the box in the vise

And check the OD on those switches-a lot of them are 15/32"...

Reply to
Rick

that's right, that's what the OD is... but I do not have a 15/32 drill bit... Although, I must say, I just won a shitload of drill bits and end mills in a liquidation auction, maybe I will wait until Monday when I pick them up...

i
Reply to
Ignoramus27279

GREENLEE punch

Reply to
Eat at Sloppy Joes

Or, lacking those, a small drill bit + a hand nibbler or hacksaw.

Reply to
Tim Shoppa

There's been a wood theme to the answers. My variation is two pieces of wood, with the plate sandwiched in between. If you need to see the plate to line up the hole, pre-drill the top piece of wood. Clamp or screw the pieces of wood together, and stick the mess in your vise. That avoids bending the metal and keeps the drill from pulling it out of your clamp setup. Or, if you have some time to kill, just punch the hole with a nail and file it out to a larger size. (:

Reply to
B.B.

Greenlee punches are really good for making holes in sheet metal that's too small, flexible, fragile or inaccessible to drill, but they are fairly expensive. Otherwise use a less-grabby step drill (Unibit, etc) or drill a small hole and enlarge it by hand with a tapered reamer like this one:

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Jim Wilkins

Reply to
jim.wilkins

.50 cal BMG and file off the little burr. (Somebody HAD to say it!)

Reply to
Tom Gardner

that's the best one so far...

o

Reply to
Ignoramus27279

Reply to
carl mciver

Reply to
Tom Gardner

I used to use a plumber's tapered reamer to make holes for tube sockets. The reamer had a tapered rectangular tang that fit in a hand brace -- as in brace 'n bit. Drill a 1/4" hole and ream as needed up to about 1.5" dia.

Yow, I see that a basic Stanley brace now goes for $79, but they're on Ebay for less, and might be found cheap at garage sales or estate sales.

Uni-bits are available up to 1" dia, work very well in a drillpress (low speed, please) for making nice holes in sheetmetal.

Reply to
Don Foreman

Greenlee punches are pretty inexpensive:

Buy 'em once, use forever.

Jim

Reply to
jim rozen

Ig's concept of a "big hole' is a little different than ours : )

By the time you drill the pilot for a Greenlee, you're almost 1/2"!

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incoming

Reply to
Rick

Hole saw

Reply to
Stephen Young

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