DIY square hole punch press

[bobs409]

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)

[C-Bag]

Brilliant bobs409!

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

[Ralphxyz]

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

[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.

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.

[DIYer]

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:

Square Hole Punch Press by bobs409

tags: press, square, punch

[hilerioal@outlook.com]

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.

[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.

[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

thick wall impact sockets would be best even if they were Chineseium and the material was not too thick

[Toolmaker51]

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.

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/

[Metalmuncher]

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

thick wall impact sockets would be best even if they were Chineseium and the material was not too thick

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