Tapered Reamer, Hole Saw, Metal Punch?

[Krakit]

I need to bore out some quarter inch holes in a Raxxess plate designed for installing quarter inch phono jacks.

I'm going to be putting in six MIDI 5 pin DIN sockets into this and the DINS are about 1/2" in diameter.

Since I need to add another quarter inch to the exiting hole, what should I use? I'm sure that others have successfully faced this dilema before, what did you do?

I'd like to get this done in a fast efficient manner and leave a clean surface when I'm done. However, I don't want to spend a fortune on tools.

Thanks,
Carl

 

[frederic]

Use the appropriately larger drill bit, in a drill press, and clamp the panel down to a piece of wood on the press tray, using either a plastic clamp or a metal clamp with a small piece of cardboard under the foot, to avoid scratches.

Reamers make beveled holes, so one side of the panel will have a slightly larger opening than the other. Also, reaming by hand in steel generally results in star shaped holes rather than round. This happens with aluminum also, depending on the grade. The biggest mistake people making reaming holes is applying too much pressure. Like with all cutting tools let the cutting surface do the work.

If you do not own a drill press (table top $99 model is fine), see if one of your friends have access to one. You can enlarge holes with a hand drill, but enlarging holes in metal affords you the risk of the larger bit "biting" and you can seriously injure your wrists this way. Also, the bit *will* walk a little bit.

My floor-standing Delta drill press is probably my most used machine, but for this purpose you really don't need anything that big and massive. You just need the stability of holding the bit at true vertical. You probably can even rent one for what it would cost to buy a reamer, the reamer grip, and make nice round holes!

You asked about punching... there are three types. The cheap type you just hold where you want to make the hole, and beat it with a hammer. It only works on thin material (like your panel), but the drawback is it will warp the panel around the hole.

The right way to do it is the bolt-through punch, which has a bottom piece, and a top piece, and a hardened bolt that goes through the center of the two pieces, and the panel. Then with a breaker bar or an impact gun, you tighten it and it pierces the panel. That's how I make panels that contain oddly shaped openings, for RS232, RS422, VGA type connectors, the d-sub connectors. I have a set of punches for those. And they weren't cheap.

The only real way to punch without damaging a thin panel is a hydraulic punch, and for 4-6 holes, forget it. Drilling is by far easier and less costly.

 

[RICK FITZPATRICK]

and clamp the panel down to a piece of wood on the press tray, using either a plastic clamp or a metal clamp with a small piece of cardboard under the foot, to avoid scratches.

ABSOLUTELY DO NOT ENLARGE holes in sheetmetal WITHOUT a clamp, especially with a hand drill. Been there, done that with no clamp. Just about tore the end of my finger off when the drill bit engaged and caught the metal, yanked it out of my hand, made one rotation and caught my finger which it now twisted into the 1/2" drill bit and proceeded to "demeat" the bone.

AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH!!!!!

How do you spell M O R O N? (I D I O T)

There is no such thing as "simple looking operations" involving tools. Even hammers are dangerous. Been there done that too The end of my middle finger on my left hand is now wider than my right one

BTW, on holes like this, you may end up with a warped panel, as the bit has to shear in a twisting motion. To prevent this, drill SLOWLY. Do NOT push. When it exits the other side is when it usually grabs, as the last shread of metal wants to climb the void in the bit, but can't. You can de burr with large countersink so the plugs and nuts draw up flat. If the panel "twist warps, use a small heavy piece of piece of metal as a backer mass, to flatten with a hammer.

fitZ

 

[Krakit]

Of course all of this advice is coming to me after I've already purchased a knockout punch. (A Greenlee Slugsplitter, good brand)

I have high hopes for this tool and suspect that it will work nicely.

I'll let you know if it doesn't.

Carl

 

[frederic]

Punches work fine, make really nice clean holes in thin steel and aluminum.

its also more expensive than a drill bit. My advice was based on you not having any tools

 

[dragonworks]

there are drill bits designed just for sheet metel. If you use a regular drill, just as she is about to break through, ease off of pressure, the plate will have a tendency to pull the bit through. Also if the plate is thin enough, a drill will probably not give you a round hole either, thats what sheet metal bits are for. You should not use a reamer for a hole unless you have drilled it out to a sixty fourth of an inch or less than the size desired. If the hole is not round the reamer will have a hard time following the hole. If the hole is round, the reamer will work fine.