DIY square hole punch press

[wb8nbs]

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.

[Frank S]

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.

[Ralphxyz]

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

Ralph

[Paul Alciatore]

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.

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.

[Toolmaker51]

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

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.

[Jon]

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:

Bead Roller Modification by bobs409

tags: bead roller, drill, modification

Square Hole Punch Press by bobs409

tags: press, square, punch

[ChrisB257]

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

[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!

[bobs409]

Great idea.

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

Thank you!

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

[pkuphaldt]

Slick !! great idea. Paul