Knockout punch advice

Well my harbor freight set bit the dust, I made quite a few holes but it seized up and I'm unable to separate it. I've decided to just get a Greenlee, but have a question that hopefully someone with some experience can answer. I'm already over budget so why the hell not right?

While looking on ebay, I've found several sets that appear to be built so that you could use a wrench on both the die and the punch. It appears these are mostly older versions of Greenlee knockout's.

Here would be an example. Notice that the punch is not perfectly round but has flat sections to grip.

I've also noticed that the brand new versions of these punches do not have this feature and are perfectly round. I would think this would help get leverage when trying to punch a hole through a smaller piece such as a control panel. The harbor freight punches did not have this, thus you could only apply force to one side.

Are the Greenlee punches just that awesome that you don't need this? I'd much rather just get a new punch, but am hesitant on getting something that I might ultimately struggle with as much as I did the harbor freight ones.
I have 12 holes to punch so I really don't want something that is going to seize up after four or five uses. I realized I'm probably just jaded by the harbor freight punches but I have zero knowledge of these tools outside of this forum.

Thanks,
Ty

Greenlee punches work fine without the flat surfaces on the inside piece. The die is sharp enough to bite into whatever you are punching a hole into and hold.

not sure what the flat parts are for, but I've never used a wrench on them (my set is like that). the back part isn't meant to turn anyway; its meant to stay put and just pull through the metal. If I were you though, I'd see if I could find one with a larger bolt head for the same price. That one would probably work just fine, but that little bolt makes me uneasy. Especially if you're punching stainless or something.

Were you using any anti seize on the thread? Best look into getting some paste when you get your new punch.

strantor said:

not sure what the flat parts are for, but I've never used a wrench on them (my set is like that). the back part isn't meant to turn anyway; its meant to stay put and just pull through the metal. If I were you though, I'd see if I could find one with a larger bolt head for the same price. That one would probably work just fine, but that little bolt makes me uneasy. Especially if you're punching stainless or something.

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I agree with this completely.

If you were punching a piece that you could not hold onto with a vice or some other means, a wrench on the die would be helpful. That is not a very common situation though. Most of my kits are quite old but I always replace punches and dies with slugbusters now. These cut the slug into 4 pieces and and will not bind up like your punch did.

Thanks guys. I was thinking of the wrench on the die more more for holding instead of holding the piece of metal I was punching. I realize it wouldn't actually turn. I think I'm going to chalk this up to my lack of knowledge on the tools and the apparent inferiority of the Harbor Freight Punches.

Now just to find a good price on a Greenlee.

Any suggestions on what type of lubricant for the threads, it sounds like this would also help.

Stay away from the HF brand. If you cant swing the Greenlee go with the one from automationdirect.com. Get the one with the ball bearings. Always make sure you drill the right size pilot hole. Even if the draw stud will fit the hole the cut blank can bend and seize on the draw stud. I usually go one size larger than listed just to be safe.

MagooBrew said:

Always make sure you drill the right size pilot hole. Even if the draw stud will fit the hole the cut blank can bend and seize on the draw stud. I usually go one size larger than listed just to be safe.

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What brand are you using? I've never had this happen. I just select my drill bit size at random, as long as it's bigger than the bolt and smaller than the knockout, it always works for me. I'm using greenlee.

strantor said:

What brand are you using? I've never had this happen. I just select my drill bit size at random, as long as it's bigger than the bolt and smaller than the knockout, it always works for me. I'm using greenlee.

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I only use Greenlee. I have work as an electrician and Electrical Engineer for over 25 years and have seen many just starting out in the trade do this. They grab a bit just a hair larger than the stud and then end up galling the threads. Just trying to help.

MagooBrew said:

I only use Greenlee. I have work as an electrician and Electrical Engineer for over 25 years and have seen many just starting out in the trade do this. They grab a bit just a hair larger than the stud and then end up galling the threads. Just trying to help.

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That is good advice. I actually rarely use the 7/8 punch and just drill those holes with a step bit. If you move up to the larger draw stud for 3/4 (conduit size) and larger punches, you will notice that there is some play with the 7/8 hole. That is necessary to keep things from binding up.

MagooBrew said:

I only use Greenlee. I have work as an electrician and Electrical Engineer for over 25 years and have seen many just starting out in the trade do this. They grab a bit just a hair larger than the stud and then end up galling the threads. Just trying to help.

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I wasn't trying to discredit your experience or your advice, and I (and OP I'm sure) appreciate it. I was just stating my own experience. I don't have a whole lot of it though; I've knocked out probably <100 holes, and done it the way I described. Never had a problem. I almost exclusively use the 22mm and 30mm knockouts in mild steel control panels for pushbuttons & such. Do you think maybe that's why I've never had a problem? Is there something different about conduit boxes (or stock pots) that might introduce the problems you describe?

It is more prevelant on stainless enclosures. Also there is a big difference in knockout sets from Greenlee. They make a basic set that leaves the cut blank in one piece and some that splits the blank into two pieces. The basic set will cause problems if the pilot for the draw stud is not large enough. During the process of extraction the blank will bend slightly and get stuck on the stud. Another tip is to use a good oil on the threads of the draw stud before every use.