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How to cut a hole in sheet metal. Tip of the day 12-30-13

8.3K views 27 replies 13 participants last post by  gearheadslife  
#1 ·
Just a little tip on cutting a nice hole in sheet metal. I needed to cut open a hole in the door shell of my truck so I could relocate the window channel and it's welded in from the factory. The doors on these trucks had no hole as the whole inside of the door was painted and it only had a very small trim panel at the top. My passenger door had a bunch of holes drilled in it from some speaker installation years ago by a previous owner.



So I thought that was the perfect place to place my holes. I marked the corners of the hole using the punch it'self as a template. Then drilled holes at the center of all the locations.



Using a hole punch I made nice round corners for the hole.







Using a nibbler tin snip to cut away the majority of the metal leaving a quarter inch or so to trim with offset tin snips. Supercoup NR1 Nibbler Shears









Using Plug weld pliers I welded up the holes along the edge of the hole I cut. Plugweld Pliers



And a little clean up with a ROLOC disc, my door looks a lot better and I have my hole to correct the window channel angle.



I picked up the hole punches I have at a garage sale years ago. It was at an estate sale of an elderly man who had fallen ill and his things were being sold off. Every time I use something I bought that day (a number of nice hand sheet metal tools) I think of that man and wonder about the projects he must have made. I am honored to be using his tools I'll tell you that.

Brian
 
#4 ·
... I picked up the hole punches I have at a garage sale years ago. It was at an estate sale of an elderly man who had fallen ill and his things were being sold off. Every time I use something I bought that day (a number of nice hand sheet metal tools) I think of that man and wonder about the projects he must have made. I am honored to be using his tools I'll tell you that.

Brian
I have a Dewalt radial arm saw from my maternal Grandfather. He died in the early '60's when I was quite young so I never really got to know him well. Everytime I use the saw it's like a connection from the past...;)

Thanks for posting, nice job on the hole.
 
#7 ·
I have some old body hammers with carvings in the handles and one even has "JOE" stamped into the head. I always feel a connection with the previous owners when I use them.

Brian
 
#5 ·
Very nice, Brian. I use a hole saw instead of the punch (it's what I have) along with the nibblers, especially where I can't access the back side.

As a note, those niblers are most likely Jilson's rebranded for Eastwood - yes, I dislike Eastwood products and their often Harbor Freight quality at a higher price!!Jilson

Dave W
 
#6 ·
Mine were bought off the SnapOn truck, but you are likely right on the money being they are "Blue Point". :rolleyes: Dave, you should get some of these punches, they are very useful. I never owned a set until I fell upon these at the garage sale but they are very useful.

Brian
 
#8 ·
But wouldn't they be limited to the few sizes used in electrical conduit? Because this set has about 6 or 8 different ones from about half inch to an inch and a quarter or so.

Brian
 
#12 ·
They used to call these chassis punches because they were used to cut holes in sheet metal for vacuum tubes back in the early radio days.

I inherited a set from my dad that are in 1/16 inch increments. I don't have every size but I do have about 20 of them from 1/2 inch to 2 inches. They are indeed really nice.

I suspect the electricians sizes are still pretty common but the odd sizes may have gone out with the vacuum tubes.

John
 
#9 ·
Boy, they aren't cheap! The second one is hole saw kit and not the same thing at all. I didn't know what they went for, now I am even more pleased with mine. :thumbup:

Brian
 
#11 ·
It's hard to say Dan, my first choice is offset tin snips, nothing is cleaner than that. But you need the room, hints the need to cut away the center of the one I did with the less forgiving nibbler. You could do something similar, or you need to cut it with a die grinder and cut off wheel. Remember to protect windows as the sparks will damage them.

You could use the nibbler after drilling a small hole at each corner. The nibbler only needs about a 3/8" hole to start, you can even get away with a 1/4" but it distorts the metal some. Use the nibbler to within about a 1/16" of your final edge and finish it off with a hand file to perfection.

Brian
 
#15 ·
Thanks Denny. I already have it marked out where I need to cut it, I have lots of cutting tools, I just needed to know if there is anything out there that will make the cutting part as easy as possible, and more importantly, as accurate as possible.
 
#20 ·
You have put a barrier between you and your dreams. Somehow these common tools are keeping you from building your ride. You need to find ways to make it happen on your budget.

Brian
 
#21 ·
;) The redeeming factor is that if you're young enough, you have your whole life (however long that may be) to gather tools and work on your projects; but the icing on the cake is that when your on in years , you have everything that you need to build another and another and another. Wishful thinking, n'est pas?
 
#23 ·
I inherited a set of the Greenlee Punches from my Dad. I used them all the time until I picked up a set of Rota-Broaches. Now those are the tool of choice for cutting holes in sheet metal.
You can see a previously cut hole in this pic. They are very fast and can be used with a cutting jig.
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They make for very clean edges because these holes were getting the dimple die treatment.
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This is the lower rad mount for the Astro van I am building.
Image
 
#25 ·
My personal choice for cutting precision openings in sheet metal is a Dremel tool with cutting wheels. Slow and tends to use a lot of wheels but if you want a super clean and straight cut...
You can drill (or hole punch) corners if you like but with a Dremel it isn't necessary. You can carefully cut right to the the corner and have a perfect angle if you like. No worries of trying to trim that last bit you can't quite get at with tin snips. NO ragged edges, unless you get off your line and then go back and correct.
Hard to beat. Downs are that it's a bit slow. You use a lot of wheels. Do this a lot and you tend to use up a Dremel (I'm on my third). And the wheels tend to fragment sometimes, wear eye protection. There are little ceramic looking cutting wheels which are cheap but they don't last long and tend to explode. Sort of. Spend a bit more for the fiberglass type wheels which more resemble the full sized cutting wheels like you'd use on a side grinder. Not good for curved cuts.