# Knockout Punches



## Southeast Power (Jan 18, 2009)

core300 said:


> Hey,
> I'm wondering about knockout punches. I specifally need one with a 4.5" actual hole size so that's a 4" punch.
> 
> What I don't know is what I specifically need. If I were to buy the punches and dies used from eBay, are the actual punches and dies the same for manual and hydraulic setups? And I guess you need a bearing that costs about $140 for a 4" knockout punch, do you need that for both a hydraulic and manual setup?
> ...


The $75 hydraulic knock out set at Harbor Freight works just fine with Greelee and generic knock outs including the 3-1/2" and 4" size. The adapter fits over the draw stud perfectly.

The manual and hydraulic punches and dies are completely interchangable


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## core300 (Feb 21, 2011)

jrannis said:


> The $75 hydraulic knock out set at Harbor Freight works just fine with Greelee and generic knock outs including the 3-1/2" and 4" size. The adapter fits over the draw stud perfectly.
> 
> The manual and hydraulic punches and dies are completely interchangable


I'm not sure what you mean by adapter.

But, so if I get just the Greenlee 4" punch and die (used) with nothing else and the HF set, is that everything I need to make a hole? Or do I need anything additional for it to work?

I just don't know if I need to ask the seller to include the draw stud or anything like that with the punch and die.

Thanks,
I appreciate it


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## Southeast Power (Jan 18, 2009)

The larger two sizes have a larger hole and require a larger draw stud that screws over the regular draw stud.


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## core300 (Feb 21, 2011)

"But, so if I get just the Greenlee 4" punch and die (used) with nothing else and the HF set, is that everything I need to make a hole? Or do I need anything additional for it to work?"

Sorry to ask the question again, but I just want to clarify. There's a guy who will give me a good deal and I don't know how long he'll have the punch for.


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## Southeast Power (Jan 18, 2009)

If you buy the 4" KO, be aware that you will need the draw stud (Greenlee 1557AA Greenlee Punch Sleeve) that goes with it. It threads onto and over the standard draw stud that comes with the typical Greenlee 757 type hand pump head.

http://www.blackbookoftools.com/productimages/GRE1557AA.jpg








http://www.blackbookoftools.com/productimages/GRE1557AA.jpg


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## core300 (Feb 21, 2011)

Thanks,
That means I need the regular greenlee draw stud too, right? That one in the picture I'm assuming won't go over the Harbor Freight stud.


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## bill39 (Sep 4, 2009)

If you don't already have a KO set you might check out this Maxis unit.
It looks pretty nice and you don't need a hydraulic pump that tends to get messy and hard to deal with.

http://www.maxis-tools.com/product/maxpunch/

I haven't used this but it their other stuff seems to work well.


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## core300 (Feb 21, 2011)

bill39 said:


> If you don't already have a KO set you might check out this Maxis unit.
> It looks pretty nice and you don't need a hydraulic pump that tends to get messy and hard to deal with.
> 
> http://www.maxis-tools.com/product/maxpunch/
> ...


I'd love to have that but I don't have the money. That's something I would want in the future though.

And, I'm still little confused as to whether I need "Ball Bearing 3036AVBB" for the hydraulic setup or if that's just for ratcheting.


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## bill39 (Sep 4, 2009)

The ball bearing unit is only for smaller pipe sizes.
For the KO sizes that require the adapter sleeve you can't use the ball-bearing unit.


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## core300 (Feb 21, 2011)

bill39 said:


> The ball bearing unit is only for smaller pipe sizes.
> For the KO sizes that require the adapter sleeve you can't use the ball-bearing unit.


http://www.toolup.com/greenlee_742bb_4-conduit-size-knockout-punch.aspx

But the 4" punch comes with a bearing of some sort, a $140 bearing. I'm so confused right now as to what I need :001_huh:


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## bill39 (Sep 4, 2009)

If you're planning on using that thing then you'd better get a 48" Crescent wrench because you'll need that much leverage to turn it.

Also, based on experience, I'll bet you'll bend the sh*T out of your enclosure trying to use that.
Get a hydraulic punch.


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## core300 (Feb 21, 2011)

bill39 said:


> If you're planning on using that thing then you'd better get a 48" Crescent wrench because you'll need that much leverage to turn it.
> 
> Also, based on experience, I'll bet you'll bend the sh*T out of your enclosure trying to use that.
> Get a hydraulic punch.


http://www.harborfreight.com/hydraulic-punch-driver-kit-96718.html
That's what I'm planning on using to drive the 4" Greenlee punch. I just don't know what I need for it to work with the hydraulic driver. Because I can get the punch die and draw stud alone for cheap from a guy but I don't know if I need anything else.


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## bill39 (Sep 4, 2009)

core300 said:


> http://www.harborfreight.com/hydraulic-punch-driver-kit-96718.html
> That's what I'm planning on using to drive the 4" Greenlee punch. I just don't know what I need for it to work with the hydraulic driver. Because I can get the punch die and draw stud alone for cheap from a guy but I don't know if I need anything else.


The ball-bearing unit won't be needed if using a hydraulic punch.


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## electricalperson (Jan 11, 2008)

in my experience its not a good idea to use a hydraulic tool with the 4 inch punch. sometimes it blows the seals on the tool. i used to use a big ball bearing draw stud. it had a smaller bolt that you held with a wrench and a larger bolt that you turned and pulled the cutter into the cup


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## oldtimer (Jun 10, 2010)

Anyone know if crown cutters can be sharpened successfully? :001_huh:


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## rexowner (Apr 12, 2008)

bill39 said:


> If you're planning on using that thing then you'd better get a 48" Crescent wrench because you'll need that much leverage to turn it.
> 
> Also, based on experience, I'll bet you'll bend the sh*T out of your enclosure trying to use that.
> Get a hydraulic punch.


WTF? I have made plenty of pefect 4" holes with a greenlee punch with a
hand wrench 12-15 inches long. It is no big deal.


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## core300 (Feb 21, 2011)

electricalperson said:


> in my experience its not a good idea to use a hydraulic tool with the 4 inch punch. sometimes it blows the seals on the tool. i used to use a big ball bearing draw stud. it had a smaller bolt that you held with a wrench and a larger bolt that you turned and pulled the cutter into the cup


I think I'll be okay with it because I need it for the thinner steel.


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## varmit (Apr 19, 2009)

Long ago Greenlee made, in the larger sizes, actual knockout CUTTERS instead of knockout PUNCHES. They were size specific tools that each one only cut one size hole. They had a frame with a cutting wheel, similar to the cutting wheel of a pipe cutter, on each end of the frame. You turned a large nut on the frame and the cutter wheels revolved around the center drive bolt cutting the knockout. There was a die/ guide on the other side, of the enclosure that the drive bolt screwed into. i do not remember the Greenlee number, nor do I have a picture. I have not seen one of these tools since I was just a kid. I do remember that as long as the cutting wheels were sharp, these tools would cut a KO easier than a KO punch. I suppose that hydraulic punch sets made these obsolete.


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## core300 (Feb 21, 2011)

varmit said:


> Long ago Greenlee made, in the larger sizes, actual knockout CUTTERS instead of knockout PUNCHES. They were size specific tools that each one only cut one size hole. They had a frame with a cutting wheel, similar to the cutting wheel of a pipe cutter, on each end of the frame. You turned a large nut on the frame and the cutter wheels revolved around the center drive bolt cutting the knockout. There was a die/ guide on the other side, of the enclosure that the drive bolt screwed into. i do not remember the Greenlee number, nor do I have a picture. I have not seen one of these tools since I was just a kid. I do remember that as long as the cutting wheels were sharp, these tools would cut a KO easier than a KO punch. I suppose that hydraulic punch sets made these obsolete.


Sounds interesting.


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## core300 (Feb 21, 2011)

Guys,
Just want to say thanks for your help. I just purchased a 4" knockout Punch with the draw stud and sleeve for $150 shipped in very good condition. And i came along with a 3.5" punch and die too. So how did I do? :thumbup:


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## electricalperson (Jan 11, 2008)

to sharpen the die you need to sharpen the cup and not the other part.


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