Making A Square Hole In Stainless Steel

You can get a square punch set (male, female) that are used in iron workers. You then set them up in a inexpensive hydraulic press. You will need to make alignment carefully so the male die comes through into the female or you will bugger up the dies.

A square die set of that size should be available from most metal worker supply dealer. I would guess, maybe 30 bucks or so but it would last a long time, with care.

It doesn't seem like that would work well for material that may go over an inch thick. And since I may need to make a lot of accurate 1/4" holes in the 1/16" stainless for my present project, this would seem to be very tedious.

But I guess that I have no choice and will have to go the drilling and filing route for now, unless someone can recommend a small punch/die/press combo that would make those 1/4" round holes square. Anyone?

After that I'd just have to worry about getting more equipment for the bigger, deeper holes in the future.

Thanks.

Darren Harris Staten Island, New York.

******************************************************************************************************** JR North wrote:

You have not said how far from an edge you are needing the holes. These folks are among the best at punching holes:

look at their choices under punching. The cost goes up with thickness, size of hole, and distance from edge.

(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

Nothing can be outsourced, and I'd need the tools and know-how for future projects anyway.

These particular squared holes will be about 1/8" from the edges(corners) of the stainless steel.

The square holes are necessary because I'm creating a hinge set-up where I'll need put squared Delrin bushings with round holes through them into the square holes created in the 1/16" thick stainless steel. The holes need to be square so that only the rod that will go through the bushing will turn and not the bushing itself.

BTW. Can anyone tell me if there were logistical reasons why square hole bits were not made for a tool like the Rotabroach?

Thanks a lot.

Darren Harris Staten Island, New York.

then go to their site. They make tools so that you can do you own punching, they would not do it for you if you wanted them to. I'm sorry if I worded my first post poorly, I thought it was quite clear that they manufacture tools. If you are close to the edge, you can probably get by with their lightest weight tools.

(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

Darren,

Dumb question: do the holes need to be square, or merely have flat sides? If the corners could be rounded, you could mill windows using a small-diameter endmill. Cutting SS will make it more fun than simply milling a window w/o undercutting (which is a good challenge in itself), but I suspect you could do it. If there is an SS-related problem I am missing, others will correct the record.

I am a little confused about the rotation constraint. Is there only one hinge on each plate? If so, it seems very likely to bind??? If there are two or more, it should not be able to rotate even with round holes.

Sorry if I am completely missing your point, which seems likely :)

Bill

Darren,

Funny how things make sense only after pusing the send button - it sounds as though you are trying to get something to turn, and to hold the bushing in place. If that's the case, then scratch the two-point comment, but it seems that a window would work if you are willing to round the corners of the bushings, or if you deliberately undercut the corners to make room for the corners of the bushings. The bottom line is that you might consider doing something simple with the SS that gives you the same effect as a square hole in it.

Bill

Thanks. I e-mailed Roper Whitney in hopes of finding the smallest tool I'll need to get done what I want. I just can't seem to find out if they have square die/punches on their site.

Darren Harris Staten Island, New York.

******************************************************************************************************** DanG wrote:

Here's a clarification.

Imagine a 4" X 4", 1/16" thick stainless steel plate layed flat with four stainless steel rods sticking out from each corner.

To accomplish this, I'll have to cut a 1/16" slot in the end of the rods so that each rod can slide over it's corner of the plate. Now there will also have to be holes drilled down into each rod *and* through the plate so I can drop a Delrin cylinder through each of them.

Concentrating on one corner, since the plate which is only 1/16" thick will over a relatively short time cut into the Delrin cylinder because of it's turning motion, I have to place a Delrin bushing in the plate hole first, and the bushing has to be square so that it does not turn. And if the bushing doesn't turn the plate will not cut into it.

Thanks a lot.

Darren Harris Staten Island, New York.

The first thing you need to know is how many tons of force you need to punch a

1/4" square hole in 1/16" stainless sheet. The second thing you need is the smallest and cheapest tool which can yield that tonnage. I had a Whitney Jensen Model 91 10-ton bench punch which would have worked perfectly for you, but I suspect you may be able to get away with 5 tons, in which case you can use a No. 8 hand punch like you can order a 1/4" square punch/die set from a lot of people. If you get lucky when you buy the punch, you may be able to solve your problem for under $100. Punching is *always* the way to go for sheet metal.

By the way, when the time comes to actually punch, lay out the centers of your holes, and carefully centerpunch them. Then after the part is all centerpunched, put the part in the punching tool and feel with the tit on the tip of the punch until it picks up your centerpunch mark, then keeping it firmly located in the punchmark, punch the hole. That's how to put holes right where you want them.

GWE

snipped-for-privacy@mail.c> Bill Schwab wrote:

Funny you should point to that Ebay auction. I had sent the seller an e-mail asking for more info on that.

Can you tell me what a normal price is for one of those?

Thanks.

P.S: I'm still waiting for Hougen and Watts Brothers to get back to me concerning bits that make square holes.

Darren Harris Staten Island, New York.

Go to any one of their pages under the "Punching" heading. Scroll to the bottom of the page. There is a picture and sizes of the punches that fit each particular punch. The very first page I sent you told how to calculate the number of tons you would need to accomplish your task.

Put your mouse on the word PUNCHING in the black band under their logo. Go to any one of their punches listed. Scroll to the bottom of that page to see available punches and sizes.

Put your mouse on the words PUNCHES & DIES in the black band. Go to the "determining tonnages" page.

(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

********************************************************************************************************

Thanks.

The problem with all that is that mild steel is assumed, and I can only assume that the charts at the bottom of those pages are showing numbers like "1/8 - 17/64" to mean thickness - hole size, even though this isn't clear.

Also, can anyone tell me what gauge("Ga") is equal to 1/16"?

Thanks.

Darren Harris Staten Island, New York.

I didn't see anything on their site which showed punching force in tons for stainless steel, only for mild steel.

GWE

Darren,

How about a square broach and arbor press? If you have some kinda of a press in your shop, a broach will do it fast & inexpensive.

Tony

These tables assume mild steel at 50kpsi. Add perhaps 30% for stainless.

A couple more things from your other posts: you will get edge effects where the metal pulls in if you try to punch within about 1x to 2x metal thickness of the edge. Your 1/8" from the edge on 1/16th material is fine. Thicker will give you trouble.

Also: punching is pretty much limited to cases where the diameter is greater than the thickness of the material. Get even close to that point and the the edges are terrible as well as lousy punch life.

The way to do the deeper holes as well as the cheap route through your early units is to drill suitable 1/4" holes, broach them us> DanG wrote:

As for interpreting the size chart for the shapes: they make square punches from 1/8"x1/8" through 9/16" x 9/16" for the No. 24 punch on this page:

Other punches do other size ranges.

Please read the last line.

It is all right where I told you to look. Here is a quotation from the page referenced

: For Irregular Shape Holes For punching irregular shaped holes (square, rectangular, obround, triangular, etc.) multiply the length of metal to be cut by the multiplier given for a 1" length in chart #4.

Example: The shear length (or total distance around a 1" x 2" rectangular hole) is 6". To punch such a hole in 20 gauge mild steel multiply 6" x 1.01 (from chart #4) = 6.06 tons. For stainless steel this would be 6 x 1.50 = 9.0 tons.

Please read the last line. They use a simple multiplier to calculate tonnages for stainless steel.

(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens) snipped-for-privacy@7cox.net

If indeed your future needs will be through one inch thick material, might I suggest broching.

For a one inch through broach of 1/4 square, I'd guess a pretty serious hydraulic setup....which of course requires the correct sized hole to start with. A 1/4 square broach is a pretty flimsy tool and breaks real easy.

Good luck!

********************************************************************************************************