Removing Cross-Threaded Screws from Hardware?

TeaDaemon asks: "I currently have an expensive (dual CPU) motherboard mounted in a rack case. One of the mounting screws is cross-threaded, preventing me from removing the board. The case is designed to prevent access to the back of the risers, so that's not an option. Does anyone have experience with this sort of problem? Can anyone suggest a reliable way of removing said screw without damaging the board or any of it's components? The screw is next to the PCI slots, and has a couple of capacitors and ICs near by. Any help would be greatly appreciated."

Comments

Small drill bit.

[sporty]

If you can use a very small drill bit and clean out the hole just like a root canal.

Be very slow, very careful and try every so often to see if you can yank out the screw w/o killing the board.

Slow yes, but it'd work.

Just a thought, might work, might not

[Webmoth]

Tools needed: 1 Dremel Moto-Tool (or equivalent) and an appropriate burr bit; 1 vacuum cleaner with smallish wand; 1 clear "safety cap" from a bottled water bottle; clear adhesive tape as needed.

Here's the idea: using the moto-tool, drill a hole in the TOP of the safety cap just big enough for the bit to pass thru. Also drill a hole in the side of the cap you can attach the vacuum cleaner wand to with the adhesive tape.

Now here's how to use it: turn the vacuum cleaner on and place your fashioned hood over the screw. The suction may keep it in place, or you may need a helper or duct tape. Now stick your moto-tool in the top of the hood and grind away. Hopefully, the vacuum cleaner will suck away the filings well enough to prevent damage to the motherboard.

Here's another thought: if you can access the edge of the motherboard, you might be able to get a hacksaw blade between the mobo and the case and cut the offending standoff off.

Re:The mechanic's friend

[sporktoast]

I recall using Superglue once in just such a situation. I had an old XT box and I wanted to shoehorn a 286 into it. The old mobo had a mounting screw that I'd managed to strip and couldn't get out to save my life. I thought about drilling it, but a friend suggested the Superglue route. I went to the hardware store and found a cheap-but-sturdy-enough nutdriver. I glued it into place, waited extra long for it to set and just removed it all together. If I'd been feeling extra thrifty (or pessimistic about possible repeat circumstances), I might have used some nail polish remover and salvaged the nut driver.

I had considered the Vise-Grip method, but even the needle-nosed models were still a bit bulky for that particular tight spot.

Re:Drill it out

[SEWilco]

I was thinking of a "shop vacuum", a drum with a filter and blower on top. Stuff gets sucked into the drum, with most of it falling to the bottom or circulating around the wall until it slows. Often called a "wet/dry vacuum" due to being able to handle water. But small canister vacuums are also popular in workplaces, and those simply have a filter bag ahead of a fan -- that would be enough for drilled metal, assuming the fan motor doesn't mind being run for as long as this takes.

Static electricity is probably created by the airflow, so you're right that caution should be taken. Probably it would be sufficient to wrap aluminum foil around the hose a few inches from the intake end, with a grounding wire connected from it to the computer case. How the foil is held doesn't matter, as long as it is not with glue that might insulate it too much. The only static build up should be in the few inches to the end, and that could be reduced with one strand of wire somewhat coiled around the tube from the foil to the end.

But you might be using a stiff wire to hold the thing in place anyway, and if that is electrically connected to the case that should be enough.

That is, instead of making a copper sheath with a grounding strap it probably is enough to anchor a wire coat hanger in some holes on the case or rack, sandpaper or file it in several places to remove any insulating covering, and twist the wire around the end of the hose to hold it in place. Use whatever level of tech you are comfortable with, it's your rescue project.

I was suggesting sucking while drilling to prevent having filings stuck to components in ways which resist vacuuming after the drilling. Should be particularly effective on the smaller filings which would otherwise be most likely to get stuck in miniscule cracks.

Don't suck in any jumpers or batteries that you can't replace.

When done, tap the hose while in operation to try to shake filings out of hose to prevent their falling out on the next project.