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Square holes in sheet metal

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Bempa

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Hi

What is the best technique to make square holes in sheet metal?
I need to make square holes that is 8,95mm x 8,95mm. Its for plastic grommets.
 
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Bempa

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I would rather not do that. To many holes and it wont look good enough.

I would like som sort of punch for it


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nine4gmc

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Sounds like you need to make something like this specifically for your size requirements.
$_35.JPG
 
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Bempa

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Yes something like that would be ideal. Do you think it would be possible to make one strong enough for such small holes?

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nine4gmc

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How thick is the sheet metal? The hole you need is rather small so it would take a small bolt for the cutter but I imagine it would work.
Also, I have used round hole punches like the square ones below on roofing tin before so these may work on your application but the only drawback is it will stretch the surrounding metal and can cause deformities.
50k5903s7.jpg
 
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AndyA

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A punch is the way to go.

Roper whitney makes good stuff. I have their 5 ton hand punch. It's round dies only, but it works great.
 
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TauntDevil

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x2 on the square drill bits. Works amazing. I have two of them for doing wiring clips on some of the cars I work on.
 
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Bempa

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I think 9mm would work also. Some are along edges and some are more in the middle. A hand punch like that would be ideal as long it can reach 120-130mm

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nine4gmc

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That's a nibbler. It cuts sheet metal by punching a die through a hole in the tool cutting a small, usually about 1/8"x1/8" or so hole in the metal. You can use it to nibble the corners out after drilling a round hole with a drill bit. You can also nibble other shapes out of sheet metal, for instance I used one in the car audio business to enlarge door speaker holes and cut filler panels etc.

It basically works like a paper hole punch but cuts smaller square cuts instead of round and is used for sheet metal instead of paper.
 
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kerrynzl

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Professur said:
And to save everyone's brain .. here's how the damn thing works.
Click to expand...

You shouldn't have let the "cat out of the bag"
It is much more lucrative when it is a "dark science" ;)

I saw these in action at a large engineering shop in China. Along with friction stir welders, 14m long lathes, and 9m swing floor mounted vertical CNC lathes.
They were all used to make Turbines and Alternators for Hydro-Electric Dams.
[they all a lasting impression on me]
This sort of technology made me realise I'm just a "Cowshed Engineer"
 
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bon3s

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Uniontown, OH
kerrynzl said:
You shouldn't have let the "cat out of the bag"
It is much more lucrative when it is a "dark science" ;)

I saw these in action at a large engineering shop in China. Along with friction stir welders, 14m long lathes, and 9m swing floor mounted vertical CNC lathes.
They were all used to make Turbines and Alternators for Hydro-Electric Dams.
[they all a lasting impression on me]
This sort of technology made me realise I'm just a "Cowshed Engineer"
Click to expand...

Company I work for has a contract to do machine guarding and safety guarding for a large company that used milling machines to the scale I didnt know existed...

There is a unit that has a table no less than 25ft across with a capacity of 200T... Total machine height is over 30ft tall... To watch these guys work on such large pieces to the .001 or smaller of precision is mind blowing !!!
 
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bimmer1980

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http://www.sterlingmachinery.com/manufacturer.php?brand=Wiedemann

These are hand operated punches that you can swap in all sorts of different shaped punches. They are the small version of turret punches that are used for CNC sheet metal fabrication. Browse ebay for replacement punch options....

Not sure, but you may be able to buy just the square punch and then set it up in an arbor press.

also look at the punches used in the electrical trades industries. I bought a small hydraulic punch set from ebay for about $125 for a variety of round dies. You may be able to get a square punch to work with this..... It made punching through sheet metal quite easy...

Of course, the other way is to get a sheet metal shop to punch it for you or to have it laser cut.....

can you post a picture of what you are trying to do? shape of the sheet metal and the array of holes?
 
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OccupantRJ

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Drill hole in A2 tool steel flat bar. File square. Mount in arbor press bed. Use round A2 tool steel rod to fit upper mount in arbor press. File to square shape. Fit into press to check fit and alignments to each other. Remove and heat each piece glowing red with flame torch. Let cool in air. Grind end of punch flat. Reinstall and use. Tools needed, drill, file, torch. Someone will tell that it has to be annealed, but I use this method regularly and see no need to anneal with the A2 and flame technique for low use tooling. In fact, I do this in a high use spline broach for both brass and steel. .040 may take a decent pull to penetrate using a smaller press. A slide hammer can be attached to the upper ram of the press to provide "persuasion" during punching. An arm can be mounted near the base plate to act as a stripper to get the punch out of the hole during retraction.
 
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Bempa

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Avesta, Dalarna, Sweden
Hi
Thanks for all the replys. A lot of good ideas. To make things clearer I have to say that what I´m doing is auto body work. I´m into late 80´s Toyotas. And it´s no secret that they rust, ALOT! And since it is becoming harder and pretty expensive to come buy OEM replacement panels I have to use aftermarket ones. Problem is that they dont have holes in them for the GTi´s , GT4´s version in dem.

Previously I have just took a selftapping screw and drilled it through the body panel. But I´m tired of that kind of repair. It´s just not a proper repair.

I want it to be square holes so I can use the right kind of plastic grommets
 
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James-W

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You can buy square drill bits for wood, they are a regular drill bit with a square frame around it that you use in a drill press. The drill bit takes out most of the material and then the square frame is very sharp and the downward force from the drill press cuts out the the corners to make the hole square. Maybe if the metal were thin enough and soft enough, one of those bits would work, at least for a few holes.
 
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