Thread: Need advice on drilling thick metal.

Andy,
More info will be needed
All you mentioned will do the job in one way or the other. Not having dealt with any shipping containers I ,for one do not how thick the metal is.

• Thickness of the metal will best determine the process used to cut your hole.
  
• Secondly the finish desired after the hole is put there,will play a part in that decision too.You will need a smooth finish to avoid cutting the lead insulation and creating an obvious electrical hazard.
  
• Thirdly the hole size ,will it have to be a minimum size needed to limit water ingress-around 40 mm for a plug.
  
• I would estimate it would be somewhere around 6mm, but I reckon Ashore will know exactly how thick a shipping container is.
  
• You also might consider a holesaw which will leave a circular hole of selected diameter yet allow the sharp cut edges to be radiused fairly easily.

Could you drill a hole to suit cable diameter and then remove the plug ,pass cable through and re attach plug ? - under direction of a certified electrical contractor of course- as none of us here would ever dream of making unauthorized electrical connections-would we fellas ?

Cheers
Grahame

I don't think the side of a container would be any more than 3mm thick so a holesaw at slow speed should do the job. Containers get their strength from the corrugated profile.

Is there special hole-saws for metal?

Yep - no unauthorized connections around here officer! LOL!

andycapp

Originally Posted by andycapp

Is there special hole-saws for metal?

Yep - no unauthorized connections around here officer! LOL!

andycapp

Yes there are, usually fairly expensive compared to the average ones for timber. Well worth the price though, as they'll cut stainless steel or timber.
If you opt for just a hole to fit the cord (not the plug) and refit the plug later, your average twist drill bit will go through the steel. Maybe put in a smaller pilot hole first. A larger hole as you planned will allow vermin in as well!

Cheers,

Whatever size hole you drill make sure you protect the cable by using a gland. The edge of the metal might cut through the cable and give you a tickle one day.

Hi Andy
If you go the hole saw route be aware that hole saws can be purchased individually but will need the arbor to able their use in a drill chuck.

Arbors come in various sizes to accommodate the range of various diameters of holesaws available.

The photos indicate the style of hole saw you would be looking for plus the arbor.

Grahame

how much would one of those be Graham? arounf 100bucks/?

Not that much

I think the last time I bought one it was about under $40 for mandrel and bi metal hole saw 35mm Pferd brand at, you guessed it -United fasteners. less than a year ago.

Grahame

Price depends on size and quality.
Try Engineering Tools - the link is to their basic hole saws. they do work well.

Originally Posted by Andy Mac

Yes there are, usually fairly expensive compared to the average ones for timber. Well worth the price though, as they'll cut stainless steel or timber.
If you opt for just a hole to fit the cord (not the plug) and refit the plug later, your average twist drill bit will go through the steel. Maybe put in a smaller pilot hole first. A larger hole as you planned will allow vermin in as well!

Cheers,

Listen to Andy, Andy. It's a bit crazy to drill such a big hole in a container when you can take a plug off in five minutes and refit it after pushing the cord through. The only further advice I'd give would be to slip some sort of strong insulation over the cord where it goes through the hole. A small length of garden hose maybe. You should be able to drill a 12mm hole with an ordinary twist bit that would accomodate this hose.

It just so happens that yesterday my Seatainer was delivered. I'm turning mine into a drying shed for timber slabs. The first thing I did was to cut a number of holes for vents etc.

The containers are indeed 3mm thick mold steel so normal steel drills go thru them very easily.

I used an 1mm kerf 115 mm diameter cutting wheel to cut 6, 150 x 200 mm vents and 2 x 300 mm diameter whirly bird exhausts. Cutting the circles with the grinder was done by cutting about a 20 sided cut.

I haven't done the power connection yet but my plan is to drill a 1" hole and use a piece of threaded black poly plumbing pipe with a poly nut on both sides as a gland for the power cable.

I'm also thinking of installing some simple fire suppression, Temp sensitive sprinklers connected to an external tap.

Originally Posted by BobL

I haven't done the power connection yet but my plan is to drill a 1" hole and use a piece of threaded black poly plumbing pipe with a poly nut on both sides as a gland for the power cable.

You might as well do it properly, Bob, and use flexible conduit with saddles and self-tappers. I like the sprinkler idea,

Originally Posted by Rossluck

You might as well do it properly, Bob, and use flexible conduit with saddles and self-tappers. I like the sprinkler idea,

Now that you have prodded me I remember where I put a couple of metres of flexi conduit! Thanks Rossl.

If you want to do it properly, why not use one of the external sockets that are used on caravans?. You don't have to worry about cutting off ends of extension cords, waterproofing and all that stuff - looks all good and proper, too.

Easy to replace the extension lead when it gets old and tired, and if you trip or run the mower over the cord, it will tend to yank out of the socket rather than transfer the stress to the cord.