School me on knockout punches

Matt68061

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Ok...I am kind of confused on the correct sizes to buy...

I am wanting to punch holes for standard sized buttons 1 1/8 inch and 2 1/4 trackballs.

I had just presumed those were the sizes of the punches I needed to buy but on several sites and Amazon listings I see the verbage "Actual hole size is..."

Are there different sizes depending on if its electrical or something?

So basically...does a Greenlee 1 1/8 cut a 1 1/8 inch hole?

Thanks in advance for any advice...

Matt
 
I bought a Greenlee 72BB, which is the one for standard 1 1/8" CP holes. For whatever reason, they are advertised using the 'conduit size' they correspond to, not the actual hole size (which I assume is to cater to electrician-speaking folks, and not the general public). So you definitely want to pay attention to what the actual hole size is, if it's listed. The 72BB is listed as 3/4" conduit size, but the actual hole size is 1 1/8".

It works well, but I've found I still need to file the holes out a bit sometimes, as they tend to be a hair too small for some buttons. But that's easier than trying to use a drill and hole saw IMO, which I tried, and it was ratty as hell. Might be easier if you have a drill press, but you still need to keep the CP secure and stable, which can be tricky, due to the size.

Here's another thread mentioning the 72BB (see post #23), which I think I found when I was researching which one to get:

http://forums.arcade-museum.com/showthread.php?t=112573&highlight=72bb&page=3
 
As an electrical contractor, they are sized for connectors, not the actual conduit. It's really a necessity or everyone on a jobsite would be seriously confused and once you punch a wrong size hole in some metal, it's a problem...

With that said instead of a knockout punch I use ideal carbide metal hole saws. They are not cheap, but they are fast an sharp.
May be an option since punches usually aren't cheap either.


This style, they can be purchased separately.
http://www.testequipmentdepot.com/i...=1100200225040&utm_content=All Ideal Products
 
Disappointed.
 

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