Need to punch a 1" Hex hole in 1/2" metal

Suggest you post this in alt.crafts.blacksmithing - the best punches are made by Grant Sarver of Off Center Forge. Most guys just use the pritchel hole in the anvil as the die.

Or, if you want to do it cold, you buy a custom punch & die for your ironworker from Cleveland Steel Tool. Better be a beefy ironworker.

Neither of these gets you a precision hex. If you need that, you're talking wire EDM or a custom made broach.

The other option is laser cutting. Maybe cheaper than buying the tooling to do it yourself, although you'll have to find your local vendor.

GWE

Yeah, what he said- For one off, or small quantities, If precise dimensions are not essential, you could make your own hex punch from drill rod from Mcmaster Carr, either machine it or forge it, with a slight taper. Get the metal cherry red, use a hammer. No die is needed.

For many of them, a punch and die for an ironworker. My ironworker is a 50 ton, it will easily do this. That is an average size for a steel fab shop. Hex dies are pretty rare, however, most guys just have round, and maybe a square or two. My guess is tooling, from cleveland, would run between a hundred bucks and two hundred, for a 1" hex. But it would last for thousands of holes.

Laser, or waterjet, for single holes that need to be accurate.

For only one, of course, there is the old Armstrong method- drill a hole, then file the hex faces in. Might take a couple of hours, but its cheap, and it works.

Greenlee also has hex punches

Gunner

"Deep in her heart, every moslem woman yearns to show us her t*ts" John Griffin

Whooops.never mind... 1/2" metal..aint gonna punch it with a Greenlee. I read to fast.

Gunner

"Deep in her heart, every moslem woman yearns to show us her t*ts" John Griffin

McMaster sells a 1" hex broach, thing costs about $500 but if you have enough to cut, or a big enough budget...

it would be more helpful if you tell what kind of metal, and how many holes you need

If I needed one hole, I'd drill most of the stock out, taper a 12 inch long piece of 1" hex rod slightly (mild steel will work for a one-off), heat the work to 2000 degrees or so and drive the hex rod through, using the hardy hole in the anvil as a bolster. This will swell the hole a little on the backside, so the angle grinder comes next. Depending on how well you can hit the hammer, be prepared to do the following: Have a pail of cool water handy. When you drive the hex into the stock, hit it HARD 3 times, drive the hex out backwards and cool the hot end in the water, hit 3 times, cool, etc. If you need many holes, the hex will need to be better steel. I'd use S1, S7 or H13.

If all this blacksmith talk interests you at all, the Arizona Artist Blacksmith Association might be a place to investigate. Go to ABANA.org to locate them. A great bunch of folks.

Pete Stanaitis

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Bob AZ wrote:

An appropriate method depends a lot on how accurate the hole needs to be, and how much distortion can be tolerated at the edges of the hole.

One approach would be to lay out and drill six small holes in the areas of the points of the hex. A single large hole could be drilled in the center to remove most of the material, then milling or grinding/filing the final shape. The location of the six small holes can be within the hex shape, if you need sharp hex points. The holes can also be outside the points by a percent of the drill diameter, if the clearance can be tolerated.

Another method could be to drill a hole about 1" in diameter, then force a tapered punch (round taper on a hex punch) through the plate when the plate has been heated to red in the location of the hole.

WB metalworking projects

If a 1" hex key is within your budget(about $20), you can certainly use it as your punch. I would choose Bondhus or Allen or some other good name. Eklind will probably work but they're not great. I've found that good hex keys are of excellent steel quality and heat treatment which makes them good for use as punches (at least for driving). They don't mushroom very much at all, and they basically won't shatter.

Sharpen the end flat with an angle grinder. Nicer keys have a slight round-over at the ends which is undesirable for this application.

I would drill a hole very close to 1" before punching. You could probably do it on a beefy arbour press with the part red-hot.

Regards,

Robin

According to Gunner :

For 1/2" thick? Look in the "Subject: " header.

I went to MSC's on-line catalog, and couldn't find hex broaches any bigger than 5/8" -- but I'll bet that they could supply them anyway, since they would know who to call.

Enjoy, DoN.

Bore hole, put in 1" hex socket, weld to material, trim to length, done.

Stan

Tool steel Not sure which strain or etc.

Bob AZ