The Sheet Metal Shop .Com

Sheet Metal Basics - Die Punching...??

toofazt - Apr 09, 2007 - 07:22 PM
Post subject: Die Punching...??

Hi. Bear with me, this is my first post here!

What would be the least expensive way to punch a clean hole 1.5"dia - 2"dia in 20ga Stainless Steel? Thanks a lot for any help! Smile

LeadHead - Apr 10, 2007 - 10:58 AM
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Greenlee Slug Buster(knock-out)maybe? It might put two small dings in the metal where it starts the hole though.
http://www.foxelectricsupply.com/conten ... =721-11/2P

Bud - Apr 10, 2007 - 12:20 PM
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I might have this unit at the shop? I'll look and if so I do have some stainless to try it on:)

rothalion - Apr 10, 2007 - 11:48 PM
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Its not cheap but depending on the amount of holes I might try something like an Edwards Ironworker. Ours does a clean .375" hole in .125" stainless steel bar stock. Its a 55 ton unit. I have to work with some 18 Ga. SS here shortly so we will see how it behaves. The best test I can do now is 22 ga. I will try that tomorrow.

Geesh! I hate Stainless steel!

toofazt - Apr 12, 2007 - 09:01 PM
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Has anyone tried what they were talking about yet? Thanks!

toofazt - Apr 12, 2007 - 09:04 PM
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For that knock out punch is it used with a hydraulic punch or what? Thanks

LeadHead - Apr 13, 2007 - 02:27 AM
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For the knock out in the link that I gave, you drill a hole the size of the bolt in the center, insert the bolt with the cup attached through the hole then thread the punch onto the bolt on the other side and tighten untill it cuts through. We have a hydraulic one with a hand pump in our tool room.

toofazt - Apr 13, 2007 - 04:19 AM
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Do you think that it would punch through 20ga stainless? Is there something like that you could use with a press? Thanks for your help Smile

toofazt - Apr 13, 2007 - 04:36 AM
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I'm looking at a GREENLEE HYDRAULIC HAND PUMP #767 on Ebay. Could someone explain how it works? Thanks for your help Smile

toofazt - Apr 13, 2007 - 04:45 AM
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And is there something like this that isn't portable? Seems like it would add to the price because of the portability...?

marky - Apr 13, 2007 - 11:02 AM
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You could use a fly press and two short pieces of pipe to protect the bolt, you should be able to punch the 20 swg using these punches using the vice and an allen key i regularly cut holes in 16 swg up to 2"dia by hand . aw ra best Marky

toofazt - Apr 13, 2007 - 07:24 PM
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Looks like I'm going to get either a Roper Whitney No. 118 or a Greenlee Slugbuster Knockout #767. What one would be better for punching 1.5" & 2" holes in 20ga stainless? Looks like they both cost about the same... I think the dies for Greenlee are conduit size. Is there a chart that shows what size hole they will actually punch? THANKS! -Steve

Stickman - Apr 13, 2007 - 10:48 PM
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The roper 118 or 218 (which I have) will do a very nice job. The punch of that size will be a split cut punch....this will make the cut much easier. I have not punched 20 ga. stainless but have done several 24 ga. I have also punched 2" holes in 16 ga. cold roll with ease....so I think it will do the stainless 20 ga. I would give Roper a call and ask. You can find the 118 & 218 on Ebay quite often....but I would buy the punches new from Roper. Current price is 83.00 for the 2" punch & die. Hope this helps.

toofazt - Apr 13, 2007 - 11:01 PM
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So would you recommend the Roper 118 over the Hydraulic Greenlee Knockout? Thanks

Stickman - Apr 13, 2007 - 11:34 PM
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Can't say....I have never used a Greenlee punch.

toofazt - Apr 14, 2007 - 05:22 AM
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Anyone here use a Greenlee punch?

rothalion - Apr 14, 2007 - 06:31 AM
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Sorry my hard drive died. I did punch a 1.0625" in 22 Ga. SS. It was very clean. The backside might, depending on your usage, need to be smoothed out I had a slight bur.. My machine only goes to that dia. and I can't break into my 18 Ga just yet for a better test, sorry.