WTF.. harbor freight hole punch set???

cueball

Active member

Donor 2011
Joined
Mar 4, 2007
Messages
3,313
Reaction score
24
Location
Coatesville, Pennsylvania
so I read the thread on here about the knockout punch sets and I decided to pick me up one. missed out on a greenlee set on CL for $30, but got the Harbor Freight one. Frankly, I think it is more work than just a hole saw since you have to drill a 3/4" pilot hole then punch the rest of the hole. with the hole saw, I would be done after drilling.

anyway, for those with the HF set, what size hole do you use? i played around with it and the 1" is too big for buttons (they fall right through) and the 3/4" is too small for buttons (microswitch buttons anyway)..

i am spending too much time on this damn control panel.. grrr.:mad:
 
Knock out punch will give you a far cleaner hole than a hole saw will. As far as the size, I cant tell you since its been a while since I did one for a button hole.
 
Standard buttons (Leaf and switch) are 1-1/8 (26mm actually), so if your buttons are falling through...they aren't standard sized buttons.
 
Last edited:
Knock out punch will give you a far cleaner hole than a hole saw will.

No disagreement there, but when you have to drill 9 holes in a cp and THEN use the punch, all for holes that are encapsulated between the head of the button and the retaining nut.

Standard buttons (Leaf and switch) are 1-1/8 (26mm actually), so if your buttons are falling through...they aren't standard sized buttons.

ahh.. i was ready to disagree with ya, but then i tried one of the new buttons that i got from Bob Roberts (instead of the old ones from the cp).. it wiggles in nicely. at least i didnt waste money on my punch set..
 
Last edited:
so I read the thread on here about the knockout punch sets and I decided to pick me up one. missed out on a greenlee set on CL for $30, but got the Harbor Freight one. Frankly, I think it is more work than just a hole saw since you have to drill a 3/4" pilot hole then punch the rest of the hole. with the hole saw, I would be done after drilling.

anyway, for those with the HF set, what size hole do you use? i played around with it and the 1" is too big for buttons (they fall right through) and the 3/4" is too small for buttons (microswitch buttons anyway)..

i am spending too much time on this damn control panel.. grrr.:mad:

I think the problem is that the label on the punch is (most likely) for electrical conduit.
Which is not the actual size listed. A 3/4" punch for conduit (EMT) is just under 1-1/8" or 28 MM a 1" is just under 1-3/8" or 34.66 MM
if I were you I'd go with the 3/4" and use a rat tail file and some sand paper to slightly enlarge the hole. Often times the hole will be warped or deformed after using a punch. Try cleaning up the hole a bit with a half round file.
 
Last edited:
Frankly, I think it is more work than just a hole saw since you have to drill a 3/4" pilot hole then punch the rest of the hole.

That's one hell of a pilot hole....I can understand your frustration. I honestly don't know what size of pilot hole I have to drill for mine.....but I know it's nowhere near that large...that's crazy.

Edward
 
Does anybody use the step drills? I bought one and haven't used it yet.
I have some step drill bits I bought from Harbor Freight a while back and those things drill very fast and easily through CP's. Unforunately I haven't found a cheap one that comes in the 1-1/8" size you need for buttons.

As for the 3/4" pilot hole, DAMN that's a big pilot hole. I have a Greenlee hole punch and it only requires a 1/4" pilot hole I believe.
 
Got mine at HF. Good to know they work well.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96275

Find a coupon (online printable) and you're good to go!

I have some step drill bits I bought from Harbor Freight a while back and those things drill very fast and easily through CP's. Unforunately I haven't found a cheap one that comes in the 1-1/8" size you need for buttons.

As for the 3/4" pilot hole, DAMN that's a big pilot hole. I have a Greenlee hole punch and it only requires a 1/4" pilot hole I believe.
 
He probably means 1/8" pilot hole...

If you gotta drill a 3/4" pilot hole, what is the point? Just drill the bloomin' 1.125" hole. I use a hole saw. Works perfectly fine... wood... metal... plexi...
 
He probably means 1/8" pilot hole...

If you gotta drill a 3/4" pilot hole, what is the point? Just drill the bloomin' 1.125" hole. I use a hole saw. Works perfectly fine... wood... metal... plexi...

Here.Here. I'm drilling a CP with like eleventy-million holes on it right now, and I find the standard, multi-use holesaw from Lowe's works just fine. Any burrs just get sanded off anyways. Now, the catch is having a good drill, not my parents POS cordless drill.
 
Actually, I use TWO Greenlee knockout punches to do metal panels. The first one requires only a 3/8" pilot hole and punches a 3/4" (19.0 mm) diameter hole. The second one punches a 28.2 mm (for 3/4" electrical conduit fittings, actual diameter 1-1/8" ) and requires a 3/4" pilot hole.

I've done so many metal control panels over the years that I wore out one punch.

Tip:

To make the punch and die last longer and cut like butter, spray the hell out of them with WD-40. This is one of the rare instances where WD-40 is actually good for something.
 
The old greenlee punches that are actually made for 1 1/8" holes (not conduit) only require a 3/8" pilot. I assume the conduit punches use a 3/4" pilot to keep the pilot size the same for large and small conduit.
 
They are also designed with a 3/4 pilot so that an electrician can enlarge a pre-existing 3/4" holes in boxes/panels and such.
 
so I read the thread on here about the knockout punch sets and I decided to pick me up one. missed out on a greenlee set on CL for $30, but got the Harbor Freight one. Frankly, I think it is more work than just a hole saw since you have to drill a 3/4" pilot hole then punch the rest of the hole. with the hole saw, I would be done after drilling.

anyway, for those with the HF set, what size hole do you use? i played around with it and the 1" is too big for buttons (they fall right through) and the 3/4" is too small for buttons (microswitch buttons anyway)..

i am spending too much time on this damn control panel.. grrr.:mad:

I, too, picked up the set of 4 punches from HF for another project that needed different sized holes, and those sizes aren't suited for buttons (one too large, one too small).

Greelee punches (1 1/8") are the best, requires 3/8" pilot hole.

Nice thing about the punches vs hole saws is that is that no matter how much you screw up the location of your pilot hole, you can adjust the position of the hole punch to be just perfect before tightening down on it. Which means you can trace your overlay holes on the metal and match them up perfectly with the punch.

I've never used a metal hole saw (used wood ones before), but would imagine anything spinning at fast speeds would be difficult to adjust positioning if your pilot hole wasn't dead-on perfect.
 
I don't know what the nominal sizes are, but I use the HFT set. The smallest punch uses a 3/8" pilot hole, so do that one first. Then take the next larger one that uses the 3/4" bolt and it goes in the hole left by the first punch. Then about 30 seconds worth of grinding with a Dremel tool and the hole is big enough for the button.

The head on the bolt takes a 1" wrench. I have one from Ace that is about 14" long which gives plenty of leverage to punch right through the CP metal.

I took some pictures the other day when I was punching the homes in the Galaga CP. If I remember tonight, I will post them.

ken
 
I'm a Greenlee dealer. Greenlee makes 3/4" pipe entrance size (smidge under 1-1/8 OD) punch and dies in both 3/8 and 3/4 draw stud sizes. Most commercial electricians use a hydraulic KO setup and the 3/4" draw stud. This same draw stud (with various spacers) can then be used all the way up to 5" pipe entrance size. The 3/8 draw stud has a short lifespan with hydraulics.

In the manual form, either is OK. Might be hard to find a Greenlee one with the 3/8 size, though. Use a step drill, aka Unibit or Varibit, to drill your pilot hole. Buy one that goes up to 7/8 max so you don't have to worry about stopping at a certain size.

They also make 3 different types of punch and die sets.
Standard -- good for mild steel up to 10ga (best value for CP's) in sizes up to 5 pipe"
Slug-Buster -- good for mild steel up to 10ga in sizes up to 2 pipe" - splits the slug for easier removal

Slug Splitter -- good for stainless steel up to 10ga (no good for CP's) in sizes up to 2" pipe

You can mix the first 2 but not the third.

Why not just use a holesaw or step bit? Certainly you can, but the punch gives you a clean hole and more importantly very accurate control of the placement of the hole.



The old greenlee punches that are actually made for 1 1/8" holes (not conduit) only require a 3/8" pilot. I assume the conduit punches use a 3/4" pilot to keep the pilot size the same for large and small conduit.
 
Back
Top Bottom