# Hole cutting



## MIGNAL (25 Jan 2014)

Not knowing much about all things metal: Is a tank cutter suitable for cutting a hole (140 mm's) in mild steel sheet? I think the sheet is about 1 mm thick, whatever gauge that is. I guess the only other alternative, with my limited tooling, is to stitch it and file.


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## porker (25 Jan 2014)

Yes a tank cutter should do the trick. What are you using as the drill? It really needs to go quite slow (around 40 rpm). Have you got anything that will go that slow?


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## Spindle (25 Jan 2014)

Hi

A tank cutter will work but will grab as it penetrates the sheet, really needs to be used in a pillar drill. A hole saw would be better as the tendency to grab will be less. Best of all would be a hole cutter







but this option is quite expensive if you only have a few holes to form.

Stitch drilling is tedious and the subsequent filing in something this thin will be a pain to support, I'd use a burr in a die grinder.

Regards Mick


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## MIGNAL (25 Jan 2014)

I only have a very small Pillar drill. I suspect that the throat depth is too small. I have various power drills with speed control. 40 RPM could be done with a hand brace! 
It's only the one hole, so spending a lot on specialist tooling is out of the question really.


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## Spindle (25 Jan 2014)

Hi

In that case I'd go for the tank cutter in a hand brace - as it penetrates and grabs back off and start a little further around - you'll end up with a series of curved slots and some 'spokes' attaching the core to the parent metal, cut these to release the core and tidy up with a file.

Regards Mick


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## CHJ (25 Jan 2014)

For a one off in sheet as thin as that I personally would go the stitch drill and file or a Jigsaw if you have one with fine metal blade rather than buy anything new, fly cutter is not easy in mild steel..

If it's a free sheet and using JigSaw, consider some scrap wood or MDF on the top of it to stop it flapping around and cut the noise down.




Even done this with thin tanks in the past by using double sided tape to hold stiffening panel in place.


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## woodfarmer (25 Jan 2014)

+1 for the jigsaw. note use very fine tooth blade and set the pendulum movement for small to nothing.


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## Inspector (25 Jan 2014)

For one hole I would look for someone that does body work on cars. Their plasma cutter would make a hole nice and quick or they may have a nibbler that would work too. What do the tool rental shops in your area have? They or an electrical contractor should have a chassis punch, what we call the hole cutter that Mick referred to.

Pete


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## Metal_Gazza (29 Jan 2014)

I would also add that it would help if you added some cutting compound/oil, etc. This will make the job a bit easier and prolong the life of your cutter.
Good luck!! :wink:


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## MIGNAL (29 Jan 2014)

Thanks for the replies. I have a Bosch metal jigsaw blade on it's way, one designed for curve cutting.
I did try a fretsaw blade, as in a jewellers piercing saw. It cut pretty fast and it's easy to cut to the line. I managed to get a quarter of the circle cut before the throat depth stopped me.


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## Eric The Viking (30 Jan 2014)

Axminster had this nibbler on offer recently. It's gone back up again, but not by much. I bought one, and although I haven't used it, it looks very good and has good reviews.

It would do your job.

On hole punches (AKA "Q-Max punches"): I've used them for many years. 

They're best in white metal cast boxes, where they leave a very good hole (I used to use them for connectors). they do work in sheet, but need to be clean and well lubricated or else they bend rather than cut (they do this when they wear out, too). The big ones need a *huge* amount of torque applied, and a thrust bearing (I've even broken bearings in the past!). You won't get one anywhere close to big enough for 140mm. 

I think your jigsaw is probably best, or a nibbler. You'll get better results if you sandwich the cut with plywood or MDF, to minimise the vibration.

E.


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