DIY square hole punch press

I recently bought a cheap (very cheap! $22 shipped) hole puncher shown in the first pic and was amazed at how nice it works. It punches round holes in light sheetmetal easily. I started to think this would be nice if they had one for square holes but a search quickly showed me there really isn't anything like that available. You can buy dies for large machines but they are very expensive.

I decided to try and make a square hole punch myself just to see if it could be done and how hard/easy it would actually work. Taking the easy approach, I opted to use sockets and socket adapters as they are already the right shape and most importantly, they are already hardened.

The male part of these extensions have a rounded edge so I ground it flat to get more of a sharp edge. The female part of the socket has a chamfered opening so I ground them down a bit to remove some of that. I used a grinder and a belt sander to do all of these.

Since I already had a nice jig made up as a finger brake press for my shop press, I simply made parts to fit it. The top piece is made so it gets sandwiched in and the bottom plate has a set screw to lock it in the correct position so the two parts meet up correctly to punch the hole. The bottom dies (sockets) have been modified with a collar either in or around them so they all fit the same recessed hole in the base plate.

I've tried 22 gauge, 18 gauge and 16 gauge sheet steel and each worked very well. I have no plans of trying anything thicker but wouldn't be surprised if it didn't work on that too.

The nicely shaped square waste pieces could be useful for filling/welding holes shut or ?? so I'm saving them being the pack rat that I am. :)

This is really in the "prototype stage" so many more improvements will be done but it is very functional as it is shown. One improvement I would do next is to add what is called a "stripper bar". NO, not that kind of stripper bar! An adjustable bar made to sit on top of the sheet metal to hold it down when the punch die is lifted back up.

To get a cleaner punched hole, I plan on removing all of the the chamfer from the sockets. As it is now, it does slightly dimple around the hole (that might even be desirable in some cases)

Attachment 19428Attachment 19429Attachment 19430Attachment 19431Attachment 19432Attachment 19433Attachment 19434

Brilliant bobs409!

I've got a ton of old sockets and extensions and this would be an excellent repurpose of them.

I wonder how hard regular sockets are? I would use impact sockets I am sure they are hardened.

Thanks for posting, got me thinking!

Ralph

Cool results, and rather surprising as well. Removing the chamfer on sockets [die] will clean up results more than same effort on extensions [punch].
The hand punch copies the Roper-Whitney Jr.; in every HVAC and duct workers box. The reason 'shaped' dies aren't made for it is twofold.
One is that neither punch or die can be fit in a tool-free change over for critical alignment. Those gauges of material matching punch capabilities are down in range of .005" and less per side, which relate to second impasse.
You'll notice, screwing in the die can position itself any height allowed by it's thread length. At extremes that prevent enough travel or such a large gap of the handles no grip could span. Limits on round sets are far less.

And to RalphXYZ: Ratchet and regular sockets are close in hardness, quality impacts are far tougher by use of shock resistant steels. Both are through hardened, thin walls and case hardening will be a brittle combination, especially in the various corners.

Please Refer to Page 2, Post #14:
Paul Alciatore makes even a more valid point on ability to punch relates to available pressure, tool strength, thickness and grade of material and punch size.....[in that] size is not diameter but measurement of circumference regardless of shape. ie a 1" hole is 3.14 circumference, 1" square = 4". That extra .86 even same thickness will require extra tonnage, tax a marginal setup, or break something already marginal.

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Thanks bobs409! We've added your Square Hole Punch Press to our Metalworking category,
as well as to your builder page: bobs409's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="http://www.homemadetools.net/homemade-square-hole-punch-press"> <img src="/uploads/204353/homemade-square-hole-punch-press.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="http://www.homemadetools.net/homemade-square-hole-punch-press">Square Hole Punch Press</a> <span> by <a href="http://www.homemadetools.net/builder/bobs409">bobs409</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/press'>press</a>, <a href='http://www.homemadetools.net/tag/square'>square</a>, <a href='http://www.homemadetools.net/tag/punch'>punch</a> </div> </div> </div> </div>
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good morning, your idea with the sockets is fantastic. you are a true yankee. (meaning a person of ingenuity and purpose) here in N.H.

Interesting idea! Now you've got me wondering, to get more assortment in hole sizes, if using the head of a grade 8 bolt, properly dressed on a grinder, pressed into a six point impact socket, could punch a hex shaped hole in the same sheet metal? If so, I think there are sockets made for square head bolts, too. That could provide an assortment of square hole punch sizes. With reference to how the punch for a rotary broach is ground, would grinding a concave in the socket-extension punch (or bolt head bunch, if that gets proven to work) help the punching operation? It would extend the 4 or 6 points of the tool out into piercing points to start the punch penetration.

As long as the material is softer than the punch and die this will work the correct profile of the punch would resemble the picture below
Attachment 19480
thick wall impact sockets would be best even if they were Chineseium and the material was not too thick

Quote:

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Originally Posted by Metalmuncher

Interesting idea! Now you've got me wondering, to get more assortment in hole sizes, if using the head of a grade 8 bolt, properly dressed on a grinder, pressed into a six point impact socket, could punch a hex shaped hole in the same sheet metal? If so, I think there are sockets made for square head bolts, too. That could provide an assortment of square hole punch sizes. With reference to how the punch for a rotary broach is ground, would grinding a concave in the socket-extension punch (or bolt head bunch, if that gets proven to work) help the punching operation? It would extend the 4 or 6 points of the tool out into piercing points to start the punch penetration.

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Function-wise and incidental usage yes. From a practical viewpoint, almost. I haven't much time this morning but offering a few details.
1. The hollow grind [punch] will cut, though suspect a short service life. More common shape is a shallow 'rooftop', or angular punch and stripper.
2. Top of socket [die] will need a shearing edge as well. Condition of die has more to do with result than punch.
3. Actual dies are tapered some what under shear-edge to release the slug. Parallel area is termed die life, to sustain repeated sharpening.
4. Without taper, the slug will stick in the effectively blind die. An undersize slug atop a stout spring may eject it. A lot like the plug retained in a hole-saw.
5. Decent cut and limited burr achieved with correct clearance; difference between punch and die, usually described 'per side'.
6. Means to secure orientation of both hexagons will be needed; rounds aren't so particular.
Following charts instruct the how and why punches function. Remainder of site equally informative. I receive no compensation for posting their information; they provided aid to me in the past, in 'My' list of honorable companies, and have a tremendous volume of equipment on the used market.
Determine Tonnage, Round or Shaped Holes: https://www.roperwhitney.com/tonnage/
Die & Punch Clearance: Allowances and Interpreting Results: https://www.roperwhitney.com/die-clearance/
Shears, as Applied to Punch Entering Die: https://www.roperwhitney.com/shears/

Quote:

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Originally Posted by Frank S

As long as the material is softer than the punch and die this will work the correct profile of the punch would resemble the picture below
Attachment 19480
thick wall impact sockets would be best even if they were Chineseium and the material was not too thick

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What advantage comes from raising the center of the bolt head, as you are showing?

I use Altoids tins for small electronic projects. For buttons I use standard 1/4" square PCB mount tactile switches. Just punch a quarter inch square hole in the Altoids lid with a hollow chisel mortise bit sans auger. It works OK but is pretty hard on the bit. Put a block of soft pine underneath the lid so the bit and punchout has a place to go.

The center is not raised the head would be hollow ground while rotating this would leave a center punch like protrusion for locating the desired hole to be punched.

Thank you Metalmuncher, I wondered the same thing about the raised center.

Ralph

I am afraid I have to disagree about the reason for no other shapes than round. The Roper-Whitney tools cost a fortune and could easily be modified to allow both the needed angular alignment with a tool free change-over and the precision needed for them to work properly. I think the real reason for this is that these hand punch tools, the R-W and the many copies of it, have a limiting diameter of about 1/4". These punches work by shearing the entire circumference at one time. So larger diameters, larger sizes would require that a longer edge would have to be sheared at once and that would take a proportionally larger amount of force. The length of the circumference of a 1/4" circle is a bit over 3/4" and that is about what these tools are capable of shearing. The fact is, that there is very little call for holes other than round that are smaller than 1/4". I have cut many, many holes in sheet metal for switches, lights, and other components and have never needed a 1/4" or smaller "D" or square or any other shape than round hole. So the reason why these hand tools do not have shapes other than round is that there is no need for small ones and the tool is not capable of the force needed for larger ones.

Greenlee makes a line of chassis punches that come in sizes from 1/2" and up. I have a collection of round ones from 1/2" up to a bit over 2" in diameter as well as several square ones, a couple of rectangular ones, "D" shaped, double "D" shape, and some others that are specific to particular electronic connectors, like the sub-D series. These chassis punches use a central draw bolt with a nut. The non-round ones use some kind of key on that draw bolt to provide the needed alignment.

Oh, one other thing, these chassis punches do not attempt to shear the entire perimeter of the shape at one time. They incorporate an angled edge on the punch that starts at two opposite points and cut at only two places at at time. But it takes a longer stroke of about 3/8" to 5/8" for the full cut. In this way, the amount of cutting force is greatly reduced. In fact, I have measured the force they need and found that a 2" diameter hole can be cut with about the same amount of force as a 1/2" diameter. Both of those punches only cut at two places at a time. It would be impractical and expensive to modify the R-W style hand punch tools for such a long stroke so that approach could not be taken with them.

I obtained this collection of chassis punches by purchasing lots of used punches on E-Bay. I usually had to sharpen them, but that is easy once you know how. By purchasing several collections, sharpening them, and then selling any duplicate sizes that I wound up with, I was able to get the collection at a greatly reduced price, almost for free. I am sure that this could still be done today and it would be an excellent way to get a collection of punches.

Quote:

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Originally Posted by Toolmaker51

Cool results, and rather surprising as well. Removing the chamfer on sockets [die] will clean up results more than same effort on extensions [punch].
The hand punch copies the Roper-Whitney Jr.; in every HVAC and duct workers box. The reason 'shaped' dies aren't made for it is twofold.
One is that neither punch or die can be fit in a tool-free change over for critical alignment. Those gauges of material matching punch capabilities are down in range of .005" and less per side, which relate to second impasse.
You'll notice, screwing in the die can position itself any height allowed by it's thread length. At extremes that prevent enough travel or such a large gap of the handles no grip could span. Limits on round sets are far less.

And to RalphXYZ: Ratchet and regular sockets are close in hardness, quality impacts are far tougher by use of shock resistant steels. Both are through hardened, thin walls and case hardening will be a brittle combination, especially in the various corners.

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Quote:

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Originally Posted by Metalmuncher

What advantage comes from raising the center of the bolt head, as you are showing?

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That presents the cutting edge more directly to area being cut, to induce a bit of shearing action vs sheer pressure. A similar action can be seen in a common paper punch or scissors. I still have to post the charts promised above, but other forms are cross-cut [criss-cross] that have 2 inclines from side to side, where they face each other in the middle is a shallow elongated X profile, like crossing your arms. Another has a middle center point; useful to locate punch on layouts, and holding the sheet in place just before punch penetrates material. Very typical in hand operated and larger portable tools.

Congratulations bobs409 - your Square Hole Punch Press is the Homemade Tool of the Week!

Huge week! Some good picks: a Sine Plate by rossbotics, a Magnetic Cutting Guide by Frank S, a Camping Stove by Tuomas, a Solder Feeding Attachment by brianhw, Stand Off Blocks by Frank S, a Punch Guide by Frank S, a Drill Guide by Frank S, a Leather Creasing Tool by frugalolgeezer, a Leather Cutter by frugalolgeezer, a Collet Rack by mars-red, a Boring Bar by xynudu, a Cable Tie Tightener by rgsparber, and a Drill Press Elevator by rgsparber.

You'll be receiving a $25 online gift card, in your choice of Amazon, PayPal, Giftrocket, or bitcoin. Please PM me your current email address and gift card choice and I'll get it sent over right away. And, we've added your tool to our All Homemade Tool of the Week winners post.


This is your 2nd Homemade Tool of the Week win! Here are both of your winning tools:

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I like this lateral thinking!! I also am a great fan of re-purposing things too. May have to give this a try.

Great idea.

Also that red.. "..a nice jig made up as a finger brake press for my shop press.." is very usefull.

Thank you!

Quote:

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Originally Posted by Tuomas

Great idea.

Also that red.. "..a nice jig made up as a finger brake press for my shop press.." is very usefull.

Thank you!

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Thank you. Here is the thread for that build and more pictures of it: http://www.homemadetools.net/forum/f...1855#post94933

It really works well and was a lot of fun to build. :)


Bob

Slick !! great idea. Paul

You have great ideas ad solution
I have a homemade press that would go nicely with square punches.
Bob Braun