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rehabhell 02-15-2010 03:24 PM

Drilled into metal in wall, now drill bit is magnetized...
Joined the board b/c it seemed like there was a lot of helpful and informed folks on here, thanks in advance for the help.

This is a good one...

We've been rehabbing this hunk of junk house with moderate success. Previous owners put all sorts of crazy stuff in and around, electrical is insane and inconsistent, screws directly into wall vents, stuff like that.

Today, my wife and I were trying to install a shelving bracket into the wall. The place she was drilling was above holes we had previously drilled and found what appeared to be the stud behind the drywall (wood shavings on the bit when coming out). However, THIS time we pull the drill bit out and there are little metal shavings all over the tip. Furthermore, the bit is now magnetized- it attracts to other metal, and the other bits in the set are not magnetic. What the heck did we drill into? There shouldn't be any plumbing as this is in the front room well away from the bathroom and kitchen. The vent duct and outlets are both on other walls, and the wall we were drilling into is shared with a stairwell with no lighting or vents. We weren't drilling on the corner of the wall, it was into the middle. This was something the previous owners built- the studs are irregular and the interior is mysterious. Anybody have any ideas?

mark942 02-15-2010 03:33 PM

A nail maybe, or worse yet a hidden electric junction box. That is all I got. Be careful.

rehabhell 02-15-2010 03:43 PM

Would a nail magnetize the bit? Is it stupid to just assume that what's done is done and screw into it, or should I open the wall?

tpolk 02-15-2010 03:55 PM

gas line, elec conduit, old table, corner strapping, car parts

rehabhell 02-15-2010 04:06 PM

Hmmm... all good guesses with this place, except it'd be impressive if they got corner strapping in the middle of the wall. Would any/all of that stuff magnetize a bit? If it was electrical conduit, do I need to open the walls to repair it? If it's any of the other stuff, should I screw into it anyway since I already made a hole? If its car parts, do you think I can get any cash for them?

tpolk 02-15-2010 04:17 PM

by corner strapping i mean the long flat strapping used as diagonal bracing usually applied to outside of exterior walls. I have used it on interior walls that were over 9' tall to help keep studs straight

Thurman 02-15-2010 04:32 PM

It sounds as if maybe he hit a metal protective plate covering a hole in a stud where an electrical wire was too close to the outer edge. Maybe the drill hit the neutral wire only. Hmm, not sure if this would have induced a magnetic field between the grounded(?) drill and the neutral though. I/ME would definitely have to open that wall area for inspection. David

tpolk 02-15-2010 04:35 PM

i agree david i would want to know

rehabhell 02-15-2010 04:52 PM

The drill is battery operated, so the only grounding it would have had would have been through my wife, who was operating it. David, from your post it sounds like you're saying the bit would only become magnetized in the presence of a magnetic field, simply drilling through metal wouldn't do it? If that's the case, it would seem to be a pretty big clue that we've hit something serious...

Snav 02-15-2010 05:02 PM

Quite honestly - it just happens sometimes and, sure, there's an explanation - but sometimes it's easier to just not scratch your hair off your head.

I craft maille all the time (chainmail - medieval armor stuff) and my pliers and rings become magnetized quite easily all the time. I think repeated/friction and heat resets the order of the metal's structured cells.

Get one of these and be happy forever - I have several and use them all the time, never fails!

rehabhell 02-15-2010 05:16 PM

Snav, that's good to hear that it can happen in the absence of electrical wires- there's still hope! I'm less worried about the bit itself than I am about what it may indicate we drilled into, but thanks for the link- that's certainly worth considering.

The wall is crummy old plaster that the previous owners attempted to cover by shoddily applying canvas. I don't want to open a big chunk of wall b/c it'll be a real pain in the butt to patch a large hole. SO, what I'm considering doing is drilling a larger hole (1/4in?) out of the hole in question, going slowly so I only drill the plaster. When I hit the metal I'll peer in and see what it is that we pierced. This way, the hole should be small enough that I can just fill it with spackle or mud to patch it. Any advice from you knowledgeable posters out there? Seem reasonable? Unreasonable? Overkill? Dangerous? Thanks so much for all the advice, everybody.

Snav 02-15-2010 08:39 PM

You can get depth-setters that go on your drill bits so they only drill 1/4, 3/8, 1/8" deep and so on - they're little screw-on stops that you slip on, tighten into place - they're awesome and sold individually or in a set in a variety of gauges (sizes) so they can fit on your bit of choice before use.
These are excellent for all sorts of projects.

There are other devices and so on that, also, register any electrical wiring - however - they only work with wiring that has a charge through it so if it's a well insulated wire then it might not register.
But I use my detector all the time - it's best to never take a shot in the dark.

william duffer 02-15-2010 10:26 PM

You could have hit some lathe material from them putting up the plaster. I would open that sucker up and see what you hit, if it wouldn't be too much work to repair it. And if you get into a sticky situation you can always make another post. I would get a non contact volt detector see if there is any live wires around, and smell for gas. If none are detected than I would start with a small hole and make it larger if needed.

Good luck

rehabhell 02-15-2010 11:22 PM

Thanks for all the tips- I'll definitely be looking more into non-contact voltage detectors; I didn't know such a thing existed! It's too late for me to be drilling a whole lot tonight, but I'll widen the hole tomorrow after work and post an update on what I find. Thanks again!

hayewe farm 02-16-2010 07:02 PM

It could be you hit metal lath. Any time you heat metal the molecules tend to line up with the earth's magnetic field.

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