Harbor Freight chassis punch kit

[MakerDP]

I think I saw in a thread somewhere that someone uses this. Was it Tubenit?

Anyways, if whoever uses this reads this... I was thinking about using this but I wasn't sure the four sizes it comes with would work for our purposes. Just what are you able to punch out with it? Are you able to use it for noval & octal sockets, pots, Cliff jacks, switches, etc?

Sure would make life easier! Now that I don't twist heater wires anymore, drilling the chassis has become my least-favorite part of the build.

[sluckey]

That set of punches is for 1/2", 3/4", 1", and 1 1/4" conduit sizes. The actual hole diameters are larger! My set of conduit punches (not HarborFreight, but should be same sizes) will make 7/8", 1-3/32", 1-11/32", and 1-11/16" actual diameter holes.

I think I've seen some 9-pin sockets that need a 7/8" hole. All my Cinch 9-pins need a 3/4" hole, so I can't use the punch for them. The only size from that set that I do use on amp chassis is the 1" conduit (1-11/32" actual size). This is perfect for mounting those 1 3/8" diameter dual cap cans that Doug sells.

I have two Greenlee step bits that I use for all other holes. The steps on the Greenlees are 1/8" so they are fine for any chassis thickness you are likely to use. BEWARE OF SOME OF THE CHEAP STEP BITS! The step shoulders are more like 1/16". They work fine on thin chassis but not so good on thicker ones.

EDIT...Just to be clear about "steps on the Greenlees are 1/8", I'm referring to the shoulder depth of cut. The diameter of each step actually increases in 1/16" increments.

[Willabe]

I have two Greenlee step bits that I use for all other holes. The steps on the Greenlees are 1/8" so they are fine for any chassis thickness you are likely to use. BEWARE OF SOME OF THE CHEAP STEP BITS! The step shoulders are more like 1/16". They work fine on thin chassis but not so good on thicker ones.

Yep, learned the hard way on that.     

I need to buy a couple of good Greenlee step bits. I did buy a # of Greenlee punches 5, 6 years back and they cost $$ but they work great. I figured they'd just go up in price so I bought them and am glad I did now.


                 Brad     

[PRR]

I'd say for most of us, punches became obsolete when step-bits arrived. Punches are a heavy investment per size, and we need several/many sizes. Step-bits cover all likely sizes in 2 or 3 bits. Punches have to be sharp and hard or the job becomes a mess. Step-bits can be/get a bit blunt and still wear-out a hole in sheetmetal. Step-bits have a limit how thick a material they will cut a clean hole, but manual punches have even lower limits before you run out of grunt or strip the pilot.

All the big-name brands offer several types of step-bits. Some are equal-steps, some give you the specific steps needed for a specific trade (conduit fittings). It can be hard to know what is being offered.

Punches are of course the thing to lust for when you want a non-round hole. And non-round punches are super expensive. The nibbler (1961) is a tiresome but inexpensive friend.

[John]

I'm waiting on a 5/8" square Greenlee punch to arrive. I got it for doing the IEC cutouts. I like the ones with the fuse incorporated. My thought is that I can make 2 punches side by side with 1 on top of those, centered. Then use the nibbler to finish off the little bits left. I'll let you all know how that works.

[terminalgs]

the HF knock-out kit is good for a few uses per punch. they begin to dull and gall eventually (like most HF stuff deteriorates).   I ended up getting some greenlee's individually off ebay.  one was new, two others used but in excellent shape.  The greenlees are (as you'd expect) much more durable.  the HF's are made with low quality steel, the Greenlees with high quality steel.


I use step-bits for everything but octal holes and holes for cap cans.  For the octals, I use a 1-3/16" greenlee (bought used, but like new...)  I use these with cinch snap-ring sockets.  Once I realized I was low on my set of NOC cinch sockets, in fear of have to buy a different sized KO, I scrambled around and found an online supplier who let me clean out is remaining stock of 30 or so. That should be a lifetime supply for me!

[sluckey]

These two step bits from Lowes (or elsewhere) will handle any round hole you are likely to ever put in an amp chassis. Not talking about screw holes.

[terminalgs]

also, drilling with a lubricant, either cutting oil, or even motor oil, will extend the life of those step-bits 2X.

[MakerDP]

Thanks for the replies everyone.

I am currently using step bits. I guess my frustration with drilling the chassis stems more from my drill press than anything else. It's an old Craftsman hand-me-down I got from my Dad and it has two shortcomings. I saw the punches mentioned elsewhere and thought maybe that would be a good solution.

First, the drill press is a smaller one. Sometimes it would be handy if I had a few more inches of depth to work with.

Second, and most frustratingly, the adjustable base plate will not fit a standard drill press vise. Clamping things securely can be a challenge especially when trying to clamp down an aluminum box and so sometimes slip happens. I could try and figure out some sort of intermediate base to line up mounting holes but then I'd be losing some more depth.

So many tools... so little money...

[John]

I'm waiting on a 5/8" square Greenlee punch to arrive. I got it for doing the IEC cutouts. I like the ones with the fuse incorporated. My thought is that I can make 2 punches side by side with 1 on top of those, centered. Then use the nibbler to finish off the little bits left. I'll let you all know how that works.

This did not work like I thought, because the pilot hole needed is actually 1/2" not 3/8". Otherwise I do think it would have worked fine. I was able to stack 1 cutout on top of the other, because top to bottom  the pilot holes needed to be 5/8" apart, so that left a bit of metal in between them.


I got the punch for $28 total, so not a big loss. And I think I'll try it on my next cutout anyway. It will just leave me the sides to nibble out.

[drgonzonm]

For those cheapo's like me, get used step drill bits from a local electrical contractor. (I got relatives who are electrical contractors) then sharpen the worn bit using a dremel.  Use 600 grit or finer paper.  It doesn't take much.     You might find a person who sharpens carbide blades for a living a source to sharpen the step drills.  (If you are paid to use step drills, then it is cheaper get a new one, than to sharpen).