Well, I've been keeping my eyes peeled for a 120mm round knockout punch tool. In my research, I've found that Greenlee makes many nice punches.


http://www.greenlee.textron.com/download/archive/45-49.pdf

For those of you who don't know what a knockout punch is, it's a tool that pucnhes a circle in metal. Generally, you drill a hole in the center, insert the draw stud, punch and die, then use a ratchet to crank it down. They make a perfect circle in minutes, nice edges, and leaves no mess to clean up.

They aren't cheap. We talking $200+. Greenlee has one that creates a 115.4mm (4.5") hole that I'm considering.

It is expensive, but I wouldn't have to rely on someone else to punch the holes, plus I've got a nice full tower SuperMicro case that is useless to me since it has eight 80mm fan mounts, which I could easily turn into three 120mm holes.

I've read the nice post on using tin snips, but to me, a punch sounds so much better. I've emailed Greenlee to see if they have a 120mm punch instead of the 115mm punch. I'll keep you posted with their reply. Has anyone seen any other punch options out there?

Greenlee is pretty standard in industry I think, as far as what I've used. You'll need some good amount of leverage for that large a hole. I've done stuff around 1-2" and need a decent wrench. Check ebay or other similar places since you don't really need a new one and maybe you'll get a deal. Or just use the money and get a case with 120mm holes.

I'm not sure of any other options, maybe a jigsaw? Actually there is this sheet metal nibbler tool, but I think it's quite expensive. It's power driven and you just push it through the metal like a power scissor.

Here

http://www.ew.trumpf.com/132.index.html

They have hand shears and nibblers, but again probably expensive.

Then there's the "rotozip" kind of tool like below. I know they're good for wood, maybe metal too? Some have the circle attachment where you make the center hole then it rotates around that hole with an arm for a round cutout.

http://shop.store.yahoo.com/boschpowert ... h1638.html

Would using a large punch require putting too much torque on the case? Do hydraulic punches eliminate the torque issue?

The speed of the punching and the die clearance are the issues. If the metal is thin, like most commerical chassis then you might get some deformation if the punch and die are not sharp and the clearance is loose. Right at the point of the tool shearing it makes a poping noise as it breaks into a large portion of the metal. You'd want to be able to keep the part still and crank the tool at this point. Some of the holes I did were a little deformed, especially if the part moves any. It takes some practice.

A power tool like hydralic is going to punch through it pretty easy.

I'd considering looking at the "rotozip" tool, or at least seeing if anyone uses that.

I looked over the rotozip info, and there is nothing in the owner's manual that says metal

I used a powered jigsaw, much like http://www.blackanddecker.com/productguide/productdetail.asp?PRODUCT_ID=2354&CRUMBS/ITEM/@ID=722_Web&CRUMBS/ITEM/NAME=Saws%20-%20Jig&CRUMBS/ITEM/LINK=../ProductGuide/ProductListSumType.asp?CATALOGID=722_Web to punch out the grills on the SLK3700. Just make sure to use it at high speed, at low speed the entire case vibrated and jumped around. Granted the edges is not perfect. With a little more care than I used you will get a better result.

A jigsaw may not be suitable for a display case, but fine for your everyday home case. The holes I cut are behind the front bezel for the intake fan and on the back, none of them directly in the line of sight.

Once I got the hang of it (second cut) the punch only took a minute to do. Plus file down some small edge gradients.

This page says steel, with some extra attachment

http://www.rotozip.com/uses/index.phtml

Oh that's with the cutting wheel.

How about putting a circular bit on a drill. I know a drill doesnt have as much torc as a dremmel, but if you push down hard enough then it should go through eventually. Plus they have circular bits that have a drill bit in the center to hold it in the hole

Actually it's possible to try a hole drill, the kind that lets you drill holes in wood for door knobs. I don't have a link, I do know someone did it for the Chilly case which is thick aluminum, course took like an hour.

Yeah. I just used one that I bought from Ace Hardware. But it is maide for doors, I don't know the size, and will cut through steel insulated doors, too. My door is steel insulated.

A drill has plenty of torque provided your blade is rated to cut through steel (harder metal, and shallower teeth).

Guys,

I think you're way off course.
Wouldn't this be a much more versatile and cheaper tool ?

http://www.directron.com/nibbletool.html

Finish it off with a Dremel or a rotating sander and your done.

edit:

and here another:
http://www.sell.com/2CTV2
and this
http://www.robotstoreuk.com/HOBBY-TOOLS/HTools-3.htm

Here's the conclusion I've come to. The best solution is the greenlee punch with hydraulics. But this is way too expensive.

So, you might be on to something with nibblers. Check out these as well:

This one may not be strong enough, as it's only rated for 20 gauge. I'm not sure how that rates compared to a normal steel computer case.



This one goes up to the usual 18 gauge.
http://www.builderdepot.com/browse.ihtml?pid=16732&step=5&prodstoreid=244#

Standard gauge for most cases is 18 GA, some cheaper ones are thinner 20 GA, and sturdier ones would be 16 GA.

This is a strange ad.
I can't think of a nibbler cutting wood.
Isn't it just a cheap saw?

IMHO:
Get good (or very good) tools, and if anyone asks to borrow them, just say NO.

Hello:

Here's something that'll make you a happy case modder:

Edit -- for some reason this pasted in weird the first and second times -- thanks Katana: http://www.dremel.com/productdisplay/att_template.asp?SKU=960-01&Color=99CCFF

It'll cut circles from 1" to 19" or 4-48cm! Cool beans.

Here is a better link:
http://www.dremel.com/productdisplay/di ... sku=960-01

Unfortunately, I know how slow dremels cut through steel. A 120mm hole would probably take 3 hours and a few blades. Too bad you couldn't turn the dremel 90 degrees and use cuttoff wheels. Those are much faster, but they don't turn well at all.

Can't beat that price though! I'm finding places to buy it for $13.

Looks like Rotozip has the same thing. I wonder how they do on metal. Probably not much different.

If you plan on doing enough holes get an hydraulic set of these greenlee punches. I have used them and they work nice. It is basically a grease gun connected to the punch.

Punching 120mm by hand will be a bitch and the onpening will definitly not be true after.

Yeah, I really want one, but they are so expensive. They never replied to my email either. Probably because I was only interested in buying 1. It says alot about a company who doesn't have the time to sell to end users. Pretty sad if you ask me.

I wouldn't say they spend a lot of time marketing these products to people like us. Go down to a good wholesale electical store or a construction store. Like where contractors buy all of their equipment, pretend like you have your own business and get them to tell you all about the products.

Are you referring to using a ratchet with a greenlee punch? Can you explain further on what would happen using a ratchet vs. hydraulic?

It is pretty hard to explain but when you really have to put a lot of force on the ratchet liter materials can start to bend outside of the radius you will be cutting.

As you apply radial force to the ratchet you will also in turn put some downward force on itwhich will deform the surrounding parts of the case.

This doesn't happen every time and may not happen to you but it sucks if you completely ruin your case.

From my experience we rarely use the ratchet punch on anything larger than a 3" diameter but even that is too large sometimes.

OK, I couldn't resist this one

Go out and buy Wiss tin snips, red + green. And a fine file, the one that is flat one side, round on the other, like this> |). And about 4sq.ft. of 22 or 24 guage sheet steel. Follow these instructions. Cut the extra sheet metal into little peices starting with many holes - practice makes perfect. When you're done, do your computer case job. File and hammer the results to remove any last imperfections.

You won't be sorry, and you will be fearless when faced in the future with any other sheet metal work. It's worth the learning.

The nibblers-saws-punches-and-all are interesting, but good old snips rule. Not trying to be staunchy here, I'm just passing on what I learned in the sheet metal shop. It will take nearly as much time just to drill the center hole for those punches as it would take to cut & file the hole thing with snips.


I haven't seen 16 or 18 guage steel cases since the IBM XT's (80's). Standard modern heavy cases are 1mm (Jap metric steel, approx. 20 guage), and lighter ones would be 22, 24, maybe with some internals parts in 26 or 28. Not too hard to cut with snips. Even 18 can be managed, but expect a good workout and some cleanup filing & hammering.

Happy modding

crisspy,
I've read your big post on tin snips many times. Thank You. I also took your advice and bought red and green Wiss tin snips. I've got a spare junked case that I'm going to practice on. If all goes well, I'm going to give it a go. I never would have if it wasn't for your post, thanks again.

Thanks Katana Man. I hope you have fun.

I do highly recommend buying a hunk of 28 or 30 guage plain galvanized (think furnace ducts) for practice. Heating/sheet metal shops have tons of smaller scraps (maybe even for free). It's nice to learn (especially the hole-spiral trick) under optimal, easy conditions, before you try on heavier/harder metal. In these lighter guages the metal just peels away like nobody's bussiness, and it gives you a good feel for the effect.

Things won't go as nicely in heavier metal, but you will know how the 'best case' is supposed to work, and can then compensate, to force the heavier metal to work in the same way. What gets harder in the heavier guages is keeping the 'cut away' metal bending up and away (it's stiffer), while the snips stay flat and square to the metal that stays. You can bend the 'cut away' up by hand or with pliers, and you can narrow your spirals down to ½" or less, so that they bend up & out easier. Remember that if you are having a hard time keeping the tin snips square and true, that it's the 'cut away' metal that is pushing on them: so force the 'cut away' to bend out of the way. Make your last spiral extra-extra narrow, like 1/8" (even 1/16"), so that it is really easy to cut cut exactly on the finish line.

Lastly, don't be afraid to make a bit of a mess. You can clean it up afterwards very easily with file and hammer+backing. I usually have to re-flatten smaller holes cut in heavy guages, but it's just a light tap-tap-tapping with a smooth-faced hammer and a heavy backing (think 1+ lbs. of steel, maybe like a small sledge hammer head). Cutting 80mm to 120mm holes barely falls in the small holes category, but other things like stamped shapes and limited space can complicate things a bit on computer cases. Sometimes you just let it make a mess crossing some little ridge or cutting close to a fold, then clean up afterwards; at least most of your hole will be tidy.

I just bought a US$1.5 tin snips to play with. But at the store they had a drill powered nibbler for US$50. Anyone used one of these? On the box it says it will cut through 1.5mm.

kogi

crisspy,
Once again, I've got to thank you for your tin snip post. I've cut my first 120mm hole, and it turned out great! I didn't even have to use a hammer to flatten anything. The hole lip is flat as a pancake

I've had this $220 Supermicro case sitting around for years:

The thing was loud because it had seven 80mm fan holes. But not for much longer I'll be putting two 120mm holes in front, and one 120mm in back. Well, my forearms are rested enough to cut another 120mm hole.

Happy to hear it worked out for you Katana Man. I'm glad it didn't get ugly, which things can sometimes do. I'm also glad that post came in usefull to somebody. I often can't help but be slightly amused at how daunting sheet metal work can be to the un-initiated. After 2 years in a sheet metal shop, most of the things that looked definitely impossible to me at first, now invoke a 'peice of cake' response. The 'how to cut a hole' dillemma is one of those frequent issues. You just have to see how it works, and try it out, to find out just how well it can be done. I guess that's why I wrote it.

I'm sure they sell to shop supply companies. You're better off contacting a local equiment company.

You may be better off still calling local sheetmetal fab shops and seeing if they'll punch the holes for you. Toolmakers love little projects. Easy for them; amazing to you.

I just finished cutting out the fan grills using some cheap tin snips (3-pack $10, red, green, yellow) and I have to say that I really miss my Dremel tool. Because they were so cheap, the edges were getting dull by the time I was finishing my second hole. The first hole looks pretty good with only a few bent edges. The second hole looks like I tried chewing through it with my teeth!

If you go this route, make sure you get QUALITY snips or you'll regret it.
Beefing up your forearms won't hurt either. Well....maybe.