Drilling a heap of 25mm / 1" holes in sheet metal

Wes, I'm not surprised that the 3/8" drive impact wrench worked to punch holes in sheet steel boxes, but I didn't have any first hand experience doing that.

It will still be noisy, but I think it's a better solution than an air ratchet.

The little 3/8" impact I have is USA Chicago Pneumatic from the 70s, and was a great tool for auto repair. I have a right-angle head accessory that is handy for reaching some obstructed fasteners, not quite as compact as an air ratchet, but really handy at times.

I was thinking that the 1/2" ratchet would have enough torque. The 3/8 impact or 3/8 butterfly impact will work just fine for sure. Small impacts have a purpose also.

I used my brothers 18v drill recently. Two screws later, I was out to my car to get my much nicer to use and hold 14.4 v drill.

Weight really matters if you have to do repetitive operations.

Wes

I would see if you can rent one of the hydraulic Greenley punch pullers. They are designed for the job, and I would think it might be the sort of thing one could rent someplace.

Doug White

If I have to do two or three, I use my wrench set. More than that I get the hydraulic tool from the tool crib.

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

The Greenlee ball screw puller is the fastest and easiset I've used for small punches. 2-3 turns with amazingly little effort for a 1/2" (7/8 dia) knockout. But a crescent wrench is quicker to take out and put away for just a couple holes.

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Ouch! Get the ball-bearing screw for it, which will reduce the required torque somewhat -- and use high pressure grease on the threads. It is still going to be a lot of work going through matierial that thick. (Hmm ... was it steel, or aluminum?) Steel will be stressing the Greenlee punch nearly 1mm thick material. Aluminum you can probably do.

Put the punch on the outside, and the die on the inside, and hold the punch in a heavy vise. (Or, I guess that you could get an open-end wrench to fit the distance between flats on the punch side of things.) Anyway -- the die goes on the inside because it will scuff the surface of the panel, so put it where it can't be seen.

The chuck itself would not be Morse taper anyway. It might have a female Jacobs taper in the back of the chuck to adapt it to a Morse taper arbor -- or directly to the spindle if it is a cheap or small drill press. Or -- the spindle might be threaded, and the chuck screwed onto that.

O.K. What about the diameter? You were mentioning either 1" or

25mm in the "Subject: " header, and they are not identical. 1" is 25.4mm, so is a difference of 0.4mm enough to be a problem for whatever is going in the holes?

I doubt it. Those are good for quick screwing and unscrewing of bolts before they tighten up, but they stall before you get to the torque you need for the Greenlee punch. (At least, the one which I have would.) You could use it for taking up the threads (those drive screws are *long*, and for backing the screw back out, but you'll have to shift to something manual for the serious part of the work. I would probably use a ratchet torque wrench (if it is within the range of the torque wrench's capacity) because it has a longer arm than the typical ratchet wrench.

This probably means that you will want two sockets to fit the Greenlee drive screw -- one for the air wrench, and one for the torque wrench.

What workpiece material? There is a wax designed to help cutting with a bandsaw (Castrol makes at least one version of it), and it might help with the aluminum if applied to the cutting edges of the punch -- but you want a good high pressure oil or grease on the threads of the drive screw.

At least with the punch side on the o8utside, you can grip the punch's flats with a good heavy bench vise (and you'll need a *heavy* bench too if you are doing steel of that thickness).

Good Luck, DoN.

The capacity of a 1" slug-buster punch is 14ga (2.0mm) in steel. A 1" slug-splitter is good up to 10ga (3.5mm) SS.

Good news. But he will still need a good solid vise to hold the punch end while he turns the screw in the die end. What is the needed torque for even 14 ga steel, let alone thicker stainless.

For that matter, how does it have greater capacity in stainless steel (3.5mm) than in plain steel (2mm). (I presume we are talking about mild steel.)

For that matter -- are those figures for turning the drive screw, or for using a hydraulic puller?

I've never had a slug-buster (slug-splitter the same?) -- they came out after I got my punches, but it would be nice to have that feature.

Enjoy, DoN.

Slug-busters and slug-splitters are different products. They both cut the punched out slug in half so it doesn't get jammed around the draw stud, and they look very similar. I'm not sure why the slug-splitters will handle heavier material. Perhaps it's the material they're made of. Slug-splitters are only for use with hydraulic or mechanical pullers, not a wrench on the draw stud.

Slug-busters have been around for at least 25 years, slug-splitters are a more recent introduction.

What's that Lassie? You say that K Ludger fell down the old rec.crafts.metalworking mine and will die if we don't mount a rescue by Sun, 21 Dec 2008 13:14:20 +0900:

Can you use a plasma cutter. Make a template to locate and size your hole. Very quick. You might need to protect the inside surfaces with a piece of scrap or something.

Dan

I may be a bit late to the party...

This 1' cube is more or less like an electrical pull box? One side removable cover and a flange on that side the cover screws onto? If so, consider the following:

1. Make an 18" square baseplate out of 3/4" plywood.

1. Screw down 1x3 hardwood cleats onto the plywood to form a 1' square opening that the enclosures will snugly seat in.

2. Attach one toggle clamp to the cleat on the open side of the enclosure and adjust it to solidly hold down the enclosure when clamped.

1. Attach this simple fixture to your drill press, positioned appropriately so that the hole location lines up with the spindle.

2. Drill the holes with a suitable step bit, hitting it with one of the dry lub sticks occasionally.

Refine this overall process as needed, upgrading the fixture to a three sided corner is needed if the enclosures tend to twist. I expect this method will let you do an enclosure every 60 seconds or so with minimal fuss, expense and cleanup.

There are some carbide hole cutters and carbide tipped hole saws at McMaster Carr page 2343.

Copied from their catalog: Carbide Hole Cutters

Great for cutting smooth, clean holes, these heavy duty hole cutters cut sheet metal, stainless steel, and plastics up to 1/4" thick. Carbide teeth are brazed into the cutter to leave smooth holes. Cutters have a spring-ejector system for easy slug removal. Shank is 1/2" dia. Pilot drill is 1/4" dia.

RogerN

Well ... I got my first chassis punch back around 1958 or so. By 25 years ago, I had all the sizes that I needed, and didn't have money to play the game of replacing them just for a new feature. :-)

Enjoy, DoN.

Seconded.