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  View original topic: Sheet metal hole punch recommendation
ncpi Sat Dec 05, 2020 9:27 am

Getting ready to do floor pans. I either want to pick up a cheap pneumatic punch or possibly a hand punch if I need to. My compressor is FL is a small 0.6 CFM.

Pneumatic punches seem to take about 4CFM. Hey, I only have about 30-40 holes per floor. Any idea what kind of cycle time I would have to deal with if I used my 0.6 CFM compressor. I'm not looking to buy a bigger compressor, but if I can punch a hole every 2 minutes it would only take an hour per floor pan :-)

Alternatively, I could buy a hand operated hole punch.

Bulli Klinik Sat Dec 05, 2020 9:39 am

I've been using a Roper-Whitney hand punch for years. There is a generic version available for about half the price on Amazon.

As a side-note, I've extended the handles on mine so that I can place it in a vice and have a bit more leverage while punching holes.

https://www.amazon.com/Capri-Tools-CP21050-21050-P...KNKR23V1X6

ncpi Sat Dec 05, 2020 9:45 am

Bulli Klinik wrote: I've been using a Roper-Whitney hand punch for years. There is a generic version available for about half the price on Amazon.

As a side-note, I've extended the handles on mine so that I can place it in a vice and have a bit more leverage while punching holes.

https://www.amazon.com/Capri-Tools-CP21050-21050-P...KNKR23V1X6

That one on Amazon is exactly the one I was looking at. Good to hear the positive feedback. how much hand force does it take to punch thru floor pans (probably 20 Ga.)?

Hand punch and cheap pneumatic are about the same price.

67ctbug Sat Dec 05, 2020 11:47 am

I use a Whitney hand punch at work, doesn't hardly take any force at least for the one I use. I'd say about the same as cutting a piece of 20 or 18 gauge with aviation snips. It may be annoying to do floor pans with, but less annoying than waiting for a compressor to catch up.

infiniteLoop Sat Dec 05, 2020 5:47 pm

A dual point drill bit (Pilot Point) or a step bit works really good on sheet metal.

ncpi Sun Dec 06, 2020 5:54 am

Thanks guys, looks like the hand punch will work. I probably won't drill even though its the cheapest route as I would rather not clean up all the holes.

I still wonder if the pneumatic punch would work well enough on my tiny compressor. Anyone tried it?

infiniteLoop Sun Dec 06, 2020 6:11 pm

The air hammers I have do not exhaust my compressor much. I would think a 3.5 and up Hp would work. I believe a air punch;that is hand held anyways , would mostly be dependent on psi and not air flow because you do not do them very fast.

Bulli Klinik Tue Dec 08, 2020 9:41 am

ncpi wrote: Thanks guys, looks like the hand punch will work. I probably won't drill even though its the cheapest route as I would rather not clean up all the holes.

I still wonder if the pneumatic punch would work well enough on my tiny compressor. Anyone tried it?

If your options are a cheapo air punch, I wouldn't bother. The quality units work well but the manual punch will always work. It also gives you the option of different sized holes. I use a couple pieces of pipe to extend the handle for additional leverage on my hand punch. My HF flanger/punch lives in the least opened drawer of my tool box for a reason. Next stop will be the garbage can.

Infinite, if you're still drilling panels for rosette welds, treat yourself to a punch. You'll see that it will be well worth the money, save you time and give you a better final product with no burrs to file.

infiniteLoop Tue Dec 08, 2020 3:00 pm

I thought I would post the other two methods because I found that they worked well. They get a perfectly round hole unlike a regular drill bit. I have a pre "Chinese flood the market' Chinese Whitney punch that works perfect.

ncpi Tue Dec 08, 2020 3:14 pm

Thanks guys...appreciate your input and the ability to learn from your experiences. I think I'll go with the hand punch.

misterh Thu Dec 10, 2020 6:40 am

ncpi wrote: Thanks guys, looks like the hand punch will work. I probably won't drill even though its the cheapest route as I would rather not clean up all the holes.

I still wonder if the pneumatic punch would work well enough on my tiny compressor. Anyone tried it?

The Harbor Freight flange/punch works for me. It only consumes air for a fraction of a second for each hole.

ncpi Thu Dec 10, 2020 7:12 am

misterh wrote: ncpi wrote: Thanks guys, looks like the hand punch will work. I probably won't drill even though its the cheapest route as I would rather not clean up all the holes.

I still wonder if the pneumatic punch would work well enough on my tiny compressor. Anyone tried it?

The Harbor Freight flange/punch works for me. It only consumes air for a fraction of a second for each hole.

Thanks! That's exactly what I wanted to know...but....I just pulled the trigger on ordering the hand punch, literally 5 minutes before your post :-( :cry:

Bulli Klinik Thu Dec 10, 2020 10:04 am

Here's the handle extension I use on my punch. You can make quick work of punching holes with the punch in a vice. I welded a flange on the lower handle in order to mount it.


In addition to punching holes for rosette welds, I use mine with an 1/8" punch to make these little tabs used to trial fit and align panels prior to welding. Benefit is that you can align the panels with no gap as opposed to the wingnut style panel clamps. Always shoot for no gaps.

ncpi Thu Dec 10, 2020 5:52 pm

Bulli Klinik wrote: Here's the handle extension I use on my punch. You can make quick work of punching holes with the punch in a vice. I welded a flange on the lower handle in order to mount it.

In addition to punching holes for rosette welds, I use mine with an 1/8" punch to make these little tabs used to trial fit and align panels prior to welding. Benefit is that you can align the panels with no gap as opposed to the wingnut style panel clamps. Always shoot for no gaps.

Nice welds! I hope I don't need handle extensions that long :o I bet the cheap chinese hand punch's die cast handles would snap :lol:

ncpi Fri Mar 19, 2021 6:58 am

Just a follow-up. I bought the capri hand punch from Amazon. It's actually pretty nice. Then when I was getting ready to punch holes I decided to get the cheap, on sale, air punch at HF.

The air punch works great on the pans I have, even with the cheap under $40 air compressor from HF. They are 20 GA. I can do a whole pan with the Air compressor only repumping once.

I ended up using the hand punch to make holes in the rubber heater channel to pan gasket. That works great too.

misterh Fri Mar 19, 2021 11:54 am

I have the HF punch/flange tool and it works great. It perfect for punching holes for plug welding.

I also have a "long reach" hand punch that I bought somewhere 30 years ago. It's good for larger holes like for the pan's body bolts.



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