Making holes in metal...

[Fuzzguitar]

Nearly finished my cab and want to add arcade pushbuttons (maybe illuminated) for EXIT GAME and POWER admin features. Problem is, how do I cut a 1 1/8 inch hole through steel approx 3mm thick? I know it can be done because I'm converting a real cab that already has those exact same size holes nearby for P1/P2 Starts.

The bit I used for the CP is only for wood, a friend was saying something about having to get an arbour that would cost around $50 AUD...

If I can't do it I'll just get small switches that can be mounted in a 10mm hole or something, what do you think?

[Tailgunner]

See if you can find a Unibit step drill bit.  Should be cheaper than a holesaw and it'll make cleaner holes in a metal panel.

[OSCAR]

Greenlee knockouts, example here, make popping holes in sheet metal very easy.  For anyone that is going to do a couple metal panels, this is a good investment.

If you are only going to do a couple holes, though, you might consider using the largest drill bit you have, and then open it up with a rotary tool and a grinder bit until the button fits.

[Apollo]

What you need to do is make a little pile of iron filings exactly 28mm in diameter where you want the hole. Then on top of that pour a little aluminium powder to form a little cone. In the top of the cone stick a small length of magnesium tape then just light the tape and stand back. Should give you a nice hole no problem. You should probably do this outside    

[Fuzzguitar]

Wow! Such speedy, helpful replies. I'll be sure to let you know it turns out.

[Tailgunner]

What you need to do is make a little pile of iron filings exactly 28mm in diameter where you want the hole. Then on top of that pour a little aluminium powder to form a little cone. In the top of the cone stick a small length of magnesium tape then just light the tape and stand back. Should give you a nice hole no problem. You should probably do this outside    

This works better if you use iron oxide (rust particles), the trapped oxygen in the rust will make it burn hotter.  

[Apollo]

He he nice tip, I'll remember that for my next metal control panel, lol.

[telengard]

Nearly finished my cab and want to add arcade pushbuttons (maybe illuminated) for EXIT GAME and POWER admin features. Problem is, how do I cut a 1 1/8 inch hole through steel approx 3mm thick? I know it can be done because I'm converting a real cab that already has those exact same size holes nearby for P1/P2 Starts.

The bit I used for the CP is only for wood, a friend was saying something about having to get an arbour that would cost around $50 AUD...

If I can't do it I'll just get small switches that can be mounted in a 10mm hole or something, what do you think?

I've cut a ton of holes in both plate steel and aluminum with a 1 1/8" bi-metal hole saw.  I've made a *lot* of panels and have only gone through 2 so far.

[menace]

I used the bi-metal hole saw as well--makes a satifying screech as it went through but it went through easy as pie--helps if you have a drill press handy.

[Radical]

Does anyone have some suggestions as to where to get sheet metal for CP usage?

Last I looked my local Lowes or Home Depot only carried small pieces (like 5x6").  But I admit that I didn't look very hard.  I'll do a better check next time I'm in the store.

I've used scrap yards to get sheet metal in the past but I'd rather have a more reliable and consistant source.

Thanks

[telengard]

Does anyone have some suggestions as to where to get sheet metal for CP usage?

Last I looked my local Lowes or Home Depot only carried small pieces (like 5x6").  But I admit that I didn't look very hard.  I'll do a better check next time I'm in the store.

I've used scrap yards to get sheet metal in the past but I'd rather have a more reliable and consistant source.

Thanks

I got mine from some steel company local to where I work.  I got 16ga steel plates made IIRC.  That's about all they would do is cut the plates though, no holes, etc.

[Setabs]

I would look back at home depot or lowes again. I found all sizes of metal up to about 2' x 4'.  What is really cool is the diamond plated sheet metal. I don't know if the prices are reasonable or not, don't buy sheet metal everyday, but its worth a shot.

[Minwah]

Greenlee knockouts, example here, make popping holes in sheet metal very easy.  For anyone that is going to do a couple metal panels, this is a good investment.

Forgive my dumb-ness, but how do you use these things?

[OSCAR]

Forgive my dumb-ness, but how do you use these things?

You can see the draw stud in the center of the punch in the photos.  What you do is use a standard drill bit to drill a hole large enough for the stud to go through in the center of  your hole.  Then you put the side with the draw stud through the hole and screw the cutter head on the backside.  Using a ratchet or box end wrench, just tighten the nut and that pulls the cutter head right through the sheet metal.  They make nice, clean holes and are actually pretty simple to use.

[Minwah]

You can see the draw stud in the center of the punch in the photos.  What you do is use a standard drill bit to drill a hole large enough for the stud to go through in the center of  your hole.  Then you put the side with the draw stud through the hole and screw the cutter head on the backside.  Using a ratchet or box end wrench, just tighten the nut and that pulls the cutter head right through the sheet metal.  They make nice, clean holes and are actually pretty simple to use.

Thanks, I think I'll give one a try...

[OSCAR]

I took a scrap mounting plate to demonstrate how nice and easy these Greenlee punches work.  Note that you need a pilot hole for the draw stud, and in the case of a 1-1/8" punch, the pilot hole needs to be at a minimum of 7/16" for the 3/8" stud to fit through.


Mounting plate and punch.




Punch assembled through pilot hole.  I tighten the cutter head up against the plate by hand.




A few turns of a 1" box end wrench or socket, and the cutter pulls right through the plate.  These punches leave a clean hole, you don't need to go back over the hole with a file.  The other nice thing about these punches is that they don't distort the panel at all, it stays nice and flat.




Put a button in, and you are done.  You may be able to find cheaper punches, but the Greenlee's are probably the best well-known for their longevity and quality.  I know a guy who has been making custom metal control panels for years, and he only uses these punches.  If you opt for a different brand, make sure it has a ball bearing (can be seen in the above pic right under the stud hex head) because that makes using them by hand vs. a hydraulic drive very easy.  I've seen cheaper punches (Eastern-made copies) without the bearing, you probably want to stay away from those.

[NIVO]

I have to agree with oscar, punches work the best, see my example as well.

[Hammerbot]

Hole saws are just as good for this application. The punches would be best if you need to use these for more than one (dozen) control panels. the hole saws can leave a chattered hole in metal but with the overhand that the buttons have, it will be covered.

1-1/8" punch = 35$
1 kit of 8 hole saws ranging from 3/4"-2" = 27$

You make the call...

[OSCAR]

I've used hole saws, step bits, & punches to make button holes in metal panels.  I agree that all will make decent holes, but I don't agree that holes saws are just as good as punches.  Maybe I'm lazy, but I don't like to go back with a file or grinder to touch up the holes after I use a hole saw.  I don't leave a sharp edge anywhere, I have enough scars on my hands already...  

All I'm saying is that since I bought a 1-1/8" punch, my hole saw and step bit have been on a shelf collecting dust.

[Ted_Striker]

Hey Oscar, you an electrician or do you just drink beers with them

I'm actually suprised this hasn't been mentioned before on this board.  I've been using them for CP's forever.  Greenlee makes a knock-out (that's what electricians call them... punch''s... baaaahhh... damn machinists   that's called the "slug buster" and it actually breaks the hole in 2 pieces.  I actually like these much better than the style you (nice pics btw.. very newb friendly) demonstrated.  I suppose each his own,  'cause they all work.  

And I also have to take issue with the "holesaw is as good"... it isn't... not for sheet metal.  You haven't used a knockout if you say that.  No offense intended.  Hole saws are cheaper and more readily available and work good.  Knockout's are better and faster but you usually can't borrow them from your "neighbor that has all the tools."  

Here's a tip:  Find the electrician's union guild hall.  Go down there with your metal in one hand and a 12pack  in the other and you will have your control panel in about 20 min ... Beer's much cheaper than both a hole saw and knockout's and you just might make a friend.

[OSCAR]

Heh, I'm no electrician...  But I've spent my share of time with tradesmen during equipment installations in plants (and maybe a beer or two after hours).

Knock-outs... yep, the trade lingo.  Just like how Iron Workers call structural wrenches spuds, huh?  On one of my first stints as a field engineer, a Millwright foreman told me that their stingers were too short.  What???  I figured out later that he was talking about the stick welder leads...  

[Ken Layton]

I'm an expert at building metal control panels. I have done the hole saw routine and it SUCKS! For the past 15 years I only use GREENLEE knockout (a.k.a. chassis) punches. They're so easy to use, fast, and last a long time. With all the panels I've done over the years, I've only worn out one punch.

TIP: here's the secret to making the holes punch thru fast and extending the life of your punch---you spray WD-40 all over the punches and draw stud for each hole you punch. You'd be surprised at how it cuts like butter. Use a Craftsman 1/2" drive ratchet handle with a 1" socket on the punch and you'll have your hole punched in 10 seconds.

[neuromancer]

One easily overlooked source of sheet metal suitable for control panels is old computer cases that you find on the side of the road.

As for hole saws, they function, and they're the cheapest. Oil helps them cut better too. And they're the only way to put a hole through a refridgerator if you want to mount a beer tap in it ;-)

Bob

[Ken Layton]

If anyone wants to buy the Greenlee 1-1/8" punch online, you can get it at www.mouser.com as their part number 586-3811 (about $40).

[JackTucky]

I have the small sqaure buttons from this Happ site:

http://www.happcontrols.com/pushbuttons/igtreplacement.htm

How do I know for sure which punch to get?

I measured the round part of the button, it's just under 7/8".  The bezel is an inch, so I should just get the 7/8"?

It makes sense, just thought I'd double check because I don't want to cut up another PC Case.  

Thanks.

[Ken Layton]

Yeh, get the 7/8" hole punch for that button. Mouser's part number is 586-3807 for the 7/8" punch (around $32). Of course if you go to Home Depot you can buy the Greenlee punch for 1/2" electrical conduit as it punches a 7/8" hole.

[JackTucky]

I bought the 1.115 metal punch at HD.  I'm going to return it today probably.  Thanks.