Broken drywall screws

rbrandenstein · **Posted:** Sat Mar 10, 2012 8:50 am

To epoxy the planking to my Malahini, I used drywall screws and some squares of scrap plywood to clamp the mahogany. I planned to countersink and plug the holes.

Unfortunately, a few of drywall screws had their heads snap off when I tried to remove them. The shaft is about an 1/8" below the surface. Since this is the deck planking and I was going to countersink and plug the hole, the embedded shaft of the screw is in the way. I also can't go off-center since the plugs would no longer line up.

Any ideas on removing or grinding off some of the embedded screw shaft so I can plug it?

Thanks.

DaveLott · **Posted:** Sat Mar 10, 2012 9:22 am

Bob - There are a number of broken screw extractors available. Find one that fits your need and does not create a hole larger than your plug.

I had several broken stainless screws that was a pain to remove. The extractor that gripped the broken tip with sharp teeth worked for me. I did not replace the screw but simply clean drilled the remaining hole and plugged it.

Regarding the broken screws. My first thought was the epoxy has a hold on them. You might to apply some heat to the future ones with a soldering iron to be sure the epoxy softens and let's go.

fergal butler · **Posted:** Sat Mar 10, 2012 9:54 am

I have a set of plug cutters that you can use to cut around a screw and then just take it out and plug it

Bill Edmundson · **Posted:** Sat Mar 10, 2012 11:10 am

Fergal

I hadn't even thought of that. :shock:

Great idea.

Bill

rbrandenstein · **Posted:** Sat Mar 10, 2012 1:10 pm

Thanks for the ideas.
The drywall screws shafts are thin and seem harder than normal screws. The normal type screw extractor does not work.

Heating it would have been a good idea, although only 6 out of about 200 broke. I'd hate to heat each one before removal. And, now that its broken I can't get a hold of it.

I do like the idea of drilling around it. I used a Dremel to cut a little channel around the screw and then removed the drill from a countersink and just chucked the counter sink. I was able to drill around it, but not deep enough to get it out.

I also have those plug cutters (at least cheapo HF ones). The smallest one (1/4" plug) has a diameter that is greater than the 3/8 plugs I want to use. Although, I'm thinking of chucking it in a drill and grinding it down to just under 3/8" while it rotates.

If I could just grind the screw shaft down, I could fit a plug. I'm going to check Dremel for a grindstone that might work.

Thanks for the advice.

Roberta Hegy · **Posted:** Sat Mar 10, 2012 2:42 pm

When I did my planks I just used the dryway screws for fitting. Once that was done I countersunk and bored the holes for the bronze screws and plugs on my drill press. That way I did not have to worry about removing the screws from the epoxy. The bores were all drilled in and once the boards were in place, I just popped in the plugs.

I like the idea of using the plug hole cutter around the broken screw. You might then be able to grab the screw shaft with a pliers and then twist it out or break it off low enough for the plug.

Roberta

upspirate · **Posted:** Sat Mar 10, 2012 5:18 pm

If you heat it first after cutting acess, you might be able to back it out like Roberta said.

I read just this same scenario on a Wooden boat forum build thread

rbrandenstein · **Posted:** Sat Mar 10, 2012 8:00 pm

Roberta: That makes so much sense. I don't know why I didn't do that. For most of the build I used these drywall screws as a temporary clamps and then went back and replaced at my leisure. I actually did break a few, but they didn't matter. On the deck planking, they do.

Anyway, I was able to get all 6 out. On the first attempt I messed up the hole a bit and will probably need a larger bung.

Here is what I was faced with.

Attachment:

IMG_0824.JPG [ 489.1 KiB | Viewed 1386 times ]

I got to this point by using a small routing bit in my Dremel to create a small hole around the screw. I need this to guide the counter sink bit. I used the bit from a drill set but removed the drill. I had to chuck this into a 1/2" chuck that I put on my cordless drill. This let me drill the countersink around the broken screw. I then used the routing bit to chew out more wood around the shaft.

Then I used a small tapered grinding bit to flatten one side of the screw. I think this also heated the shaft and help free it.

Attachment:

IMG_0825.JPG [ 493.53 KiB | Viewed 1386 times ]

I used a needle nosed pliers to get a grip. It was still a struggle to get it started, but usually once I got it moving I could get it out.

Here are the tools I used.

Attachment:

IMG_0826.JPG [ 345.39 KiB | Viewed 1386 times ]

The countersink bit just fits in a 1/2" chuck. The routing bit is 1/16" in diameter so once the countersink is drilled it fits in the hole without enlarging it. I had to be careful with the grinding stone as it was a tight fit and I didn't want to enlarge the hole.

Thanks to all for suggestions.

Roberta Hegy · **Posted:** Sun Mar 11, 2012 6:37 am

Good Job, Bob!!! Many classic boats have a few varying size bungs. They will add realism and character.

Roberta

Trackhappy · **Posted:** Sun Mar 11, 2012 5:35 pm

You can also get a small piece of thin wall metal tube a little larger ID than the screw OD and grind or file teeth on the end of it. If you use a high carbon steel of some sort you can heat and quench it to harden it a little. Chuck it in your drill and drill slowly down around the screw until it is free. It will leave you with a much smaller hole to deal with as you choose.

jprice · **Posted:** Mon Mar 12, 2012 6:04 am

This is why I gave up on using drywall screws anywhere in the build pretty early on. Just too brittle and snapped too easy.
I switched to wood screws (thicker shank, like the bronze screws) for temp fasteners, and they worked much, much better.

Anyway, glad you got the buggers out!

rbrandenstein · **Posted:** Fri Mar 16, 2012 6:39 am

A final update.

I missed two screws, so I went after them a few days later. My method described above did not work. I think the epoxy had time to really set up and I couldn't remove the screws.

However, I did find a different Dremel bit that had a small ball tip covered in tungsten carbide. This bit let me grind the shaft of the screw down in the hole. I could then twist off the shaft deep enough to permit the bung to fit.

The lesson of the day:
Do NOT use drywall screws for holding pieces you have epoxied!!

Glen-L.com

Broken drywall screws

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