Making A Square Hole In Stainless Steel

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: http://roperwhitney.com/punching/2-13.cfm . 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 (http://roperwhitney.com/tech/tech2.cfm ) : 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

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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
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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
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Bill Schwab 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.
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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 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&itemu76272205 and 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.con.com wrote:

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Grant Erwin 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.
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Someone here posted this link a while back for square hole drills. I don't know if these people are still about in the UK I think. Maybe this is what you are refering to about Hougen and Watts brothers.
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Someone here posted this link a while back for square hole drills. I don't know if these people are still about in the UK I think. Maybe this is what you are refering to about Hougen and Watts brothers.
http://www.integerspin.co.uk/polygon.htm
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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

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snipped-for-privacy@mail.con.com wrote:

I got a rotary turret punch that is in the way in my shop. The model is a Weiderman RA-41P. It's rated at 15 tons and can punch a sheet 28x 40in. The bad part is that it weighs 6000 lbs. Im about 1.45 hours away from you in NE PA. right up rt 80. I got a bunch of punches to go with it, not sure if i got a 1/4 in sq but they easy to make. The thing runs on 120/240 vac,single phase. I want $350.00 for it and will load it on your flatbed, or if no-one wants it its going to the scrapyard for .06 per pound. I have the manual for it.
I also got a 7 ton whitney jensen manual punch press that would do the job for 300.00. The whitney jenson weighs about 250 lbs. estimated.
John
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Thanks.
It seems that some here are implying that a portable hand punch/press wouldn't work for me. :-)
I'd be thinking about saving up for that, but I don't drive and I have very little room. :-(
If they made wobble bits for Rotabroaches I'd be set, since I recently won one on eBay.(http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&itemu73625865 )
Darren Harris Staten Island, New York.
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snipped-for-privacy@mail.con.com wrote:

Its not a hand punch,

I could probably get someone to deliver it.

The Whitney Jensen press is a arm crank press with a throat of about 24 inches. It really isn't portable in that the thing weighs about 250 lbs. It sits on a stand which elevates it to a good working height.
The footprint of this press is about 1.5 feet by 3.5 feet and stands about 4 feet high with the crank handle removed. The crank handle inserts into a slott on the side of the press.
The formula for the tonnage you need to punch the part is : (thickness of the metal, in inches) x (total length of the cut of the punch in inches) x (the shear modulus of the metal you are punching)
stainless steel shear will run between 90,000 and 100,000 depending on the alloy.
.062 thickness x (.25 x 4 sides) x 100,000 = 6200 lbs. or about 3.1 tons.
IF you want a picture of it send me an email.
This is the exact same press as listed on the roper whitney site. I guess they have upped the tonnage to 8 tons.
http://roperwhitney.com/punching/1-25.cfm
I have most of the die shoes and die adapters shown in this site.
John
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