# Punching Square Holes



## PHPaul (Jan 28, 2019)

I have a Whitney punch for punching small round holes in sheet metal.  Handier than a pocket on a shirt.

I build toys and models out of brass and occasionally need a small square hole, say 1/16 or 1/8 up to perhaps 3/8. 

Punching it round and making it square with a file works but is sort of tedious.  Being able to punch it square to begin with would be wicked handy.  I'm aware of the Greenlee style square punches/knock-outs, but they're too big and WAY too expensive.

Does anybody make a square Whitney-style punch?


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## RJSakowski (Jan 28, 2019)

An interesting question.  I used to use a Roper Whitney style punch on a regular basis and they re handy.  I have modified spare punches to create a custom diameter by turning down an oversized punch and boring out an undersized die.  
Offhand, I see a problem with using the Roper Whitney punch.  The punch is free to rotate so alignment with the die would be problematic. For that matter, the die can rotate as well.
If you are only looking at one or two sizes, you could make your own punch and die.  A small arbor press would be a good candidate for the press.  Make an adapter to hold the punch on the ram.  For the die, I have made it by arranging four pieces of rectangular stock, pinwheel fashion and pinning bolting to a back plate with socket head cap screws in a counterbore.  In my case, I had 6t. kick press and was punching 1/2" x 3/4" openings in 16 g. aluminum but it worked well for me until the time that I decommisioned it.  If you use this approach , you will want to machine to grind a slight relief on the underside of the die surface to prevent sticking of the slugs in the die.  I used O2 for the punch and die, hardened and tempered after machining.  Using this approach, any sized rectangular die may be fabricated.


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## PHPaul (Jan 28, 2019)

Interesting approach.  Lot of work and skills I don't currently have for a tool I'd use 2-3 times a year, if that.

I'll file it away tho.  Thanks!


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## RJSakowski (Jan 28, 2019)

I use a file for a two or three times a year part as well.  As with any labor saving alternative, you have to consider the cost of the alternative vs. the value in time savings.


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## john.k (Jan 29, 2019)

One method of making square holes is to first punch round,then use a square punch that has a keyed extension into the die thru the hole to keep the die aligned.


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## Holescreek (Jan 29, 2019)

I have a Heinrich Deep throat bench punch #6 with a lot of odd shaped punches and dies, I think the 1/8" square punch is a standard size.  http://www.heinrichco.com/metalwork.htm

I picked up a first model Roper hand punch at the flea market last summer for $3 that was missing a couple sizes and made my own punch and die sets.  I think an 1/8" square punch set would be pretty simple but the die would need to me made longer to accept a nut to keep it from rotating out of alignment. If you were careful you might get by without the nut.


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## RJSakowski (Jan 29, 2019)

Holescreek said:


> I have a Heinrich Deep throat bench punch #6 with a lot of odd shaped punches and dies, I think the 1/8" square punch is a standard size.  http://www.heinrichco.com/metalwork.htm
> 
> I picked up a first model Roper hand punch at the flea market last summer for $3 that was missing a couple sizes and made my own punch and die sets.  I think an 1/8" square punch set would be pretty simple but the die would need to me made longer to accept a nut to keep it from rotating out of alignment. If you were careful you might get by without the nut.


The square punch could be easily made but the die would be a challenge with limited tooling.  On my Roper clone, the punch is free to rotate.  It always seemed to require three hands to use the punch with the round tooling. Adding angular alignment with the work and between the punch and die would seem to me to be highly frustrating.  

Personally, I would use the file for two holes.


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## Holescreek (Jan 29, 2019)

But then you wouldn't have the satisfaction of making another tool.  You just drill a round hole in the die and file it square one time and you have a tool that will punch square holes.


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## Latinrascalrg1 (Jan 29, 2019)

What about something like this?  From what i can tell it is a normal drill press using a special square cutting bit!

https://gizmodo.com/how-the-hell-can-this-magical-square-hole-drilling-mach-5849810


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## hman (Jan 29, 2019)

Must have some kind of weird (planetary?) gearing inside the head, to oscillate/orbit the cutter.  Wish they'd show that detail!!!!


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## RJSakowski (Jan 29, 2019)

This shows the process with a little more clarity.


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## BGHansen (Jan 30, 2019)

I've got a Roper Whitney #218 punch press and do lots of square holes.  You'd have to do some heavy modifying of a #5 Junior style punch to do square holes as neither the die or the punch are rotationally constrained.  My #218 locks the punch and die from rotating so once aligned, they don't turn and scrub the sides.

Another square hole option is a nibbler.  Couple of photos of ones I use are below.  The top photo is of a popular one that runs around $12-$15.  Think you need a slightly over 1/4" hole to fit the punch through, the nibble the corners.  Lots quicker than filing.  The lower photo is of an Adel nibbler which is a heavier duty punch.

Do a Google search for "sheet metal nibbler" and you see plenty of sources for the upper one.  I bought my Adel off eBay (NOS) and replacement punches/return spring though I'm still on the original.

Bruce


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