How to remove snapped bronze screws ??? (in a hole)

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

zak99

Established Member
Joined
10 Apr 2009
Messages
81
Reaction score
6
Hi,

I need to remove a large number of snapped off silicon bronze screws in a teak deck on a wooden boat. Anyone have any tips that might help. The screws are 10g x 2 inch and snapped approximately at the top of the thread. They are in a 10mm plug hole.

I have heard of unscrew ums which may do it but I cant see them for sale in the uk anywhere.

(see my other related thread https://www.ukworkshop.co.uk/forums/help-removing-thin-deck-plugs-and-stubborn-screws-t74494.html )

rgds
 
I have seen a form of small hole saw used. Its really a small pipe with teeth on it and no centre bit. The internal diameter is just bigger than the shank of the screw. This is then drilled down over the outside of the screw. Once you have drilled deep enoungh you can pull them out with needle pliers.
 
Hi

Sorry if this sounds negative, but I think you are better looking for a solution to the job that doesn't involve removing the broken screws.

If they are broken at the top of the thread I don't think there is enough 'meat', (even if you could get hold of it), to break the bond, it will more than likely just break again.

I suppose a plug cutter type tool could be used to remove the screw and surrounding plug of teak and then bond in new plugs for screwing into - not sure if this would be robust enough.

Regards Mick
 
Andrewf":2serp9ye said:
I have seen a form of small hole saw used. Its really a small pipe with teeth on it and no centre bit.

Yes, thats good, anyone know where to get them??

Spindle":2serp9ye said:
I think you are better looking for a solution to the job that doesn't involve removing the broken screws.

I hear you Mick, if we can find a way I agree. Unfortunately we cant move the screws as all the dowels are in line across the teak boat deck, so anything out of line will look terrible.
 
Googling 'unscrewums' leads to pictures of what you describe and discussions on boat building forums. Probably feasible to order from the USA - postage shouldn't be too bad on a tiny thing like that, compared to the effort they should save.
 
AndyT":1sdytqa7 said:
Googling 'unscrewums' leads to pictures of what you describe and discussions on boat building forums. Probably feasible to order from the USA - postage shouldn't be too bad on a tiny thing like that, compared to the effort they should save.

You know you are so right there. Will probably be here in a few days. Probably before I get the ones out I have already snapped !!!
 
a screw extractor may work, which may be what Andrewf was refering to by small hole saw? Personally I'd probably just drill it out :/

never heard of unscrew ums but after googling them they look interesting, I agree with the avoid too the postage on such a small item may be worth it if they work well
 
They are available here by the look of it.

http://www.jamestowndistributors.com/userportal/show_product.do?pid=437

Personally I'd probably just drill it out :/
I tried that last week Hazel, but the snapped of screws are 15-20mm deep in a hole and inevitably the drill runs off centre and down the side of the screw.

Hmmm - Got me thinking now ... wish I could keep a 3mm router bit centred down the hole to drill out the screw ???

Anyone see the the long hole saw things anywhere??
 
From the web:

Find a small piece of tube from a hobby store. The material is not important and brass or steel will work fine. The inside hole should be the same or very slightly smaller than the diameter of the screw stuck in the wood.

File and sand the outside of the tube to a sharp point - no teeth required - just a sharp point like a small hole punch.


Lightly tap the tube over the broken screw so the sharp end fits snugly over the screw and goes about 0.5mm into the wood.

Put the tube in a hand crank drill, put the sharp end back in the small groove around the screw that you made by tapping it, and turn the drill backwards whilst pushing lightly. The tube will grip the screw and turn it out of the hole

No wood will have been removed but the edges of the hole will have been compressed, so a drop of boiling water will swell them back and when dry, a small drop of superglue will seal the wood.

Now it's as good as new and ready for the new screw which should be lubricated with dry soap to stop the same thing happening again.
 
zak99":34k3pm8v said:
Hi,

I need to remove a large number of snapped off silicon bronze screws in a teak deck on a wooden boat. Anyone have any tips that might help. The screws are 10g x 2 inch and snapped approximately at the top of the thread. They are in a 10mm plug hole.

I have heard of unscrew ums which may do it but I cant see them for sale in the uk anywhere.

(see my other related thread http://www.ukworkshop.co.uk/forums/help-removing-thin-deck-plugs-and-stubborn-screws-t74494.html )

rgds

I can't quite 'picture' the screws/situation but I used to use these (a long while ago) to remove broken studs/bolts from engines. Snap-on was guaranteed for life then (not sure if that still applies) but I never had one of these break on me.

Drill a hole into the bolt/screw, tap one in and twist the lot out. If I remember correctly, success rate was over 95%. Hope that helps.

96.jpg
 

Attachments

  • 96.jpg
    96.jpg
    210.5 KB · Views: 234
iNewbie":6xo4kjva said:
From the web:

Find a small piece of tube from a hobby store. The material is not important and brass or steel will work fine. The inside hole should be the same or very slightly smaller than the diameter of the screw stuck in the wood.

File and sand the outside of the tube to a sharp point - no teeth required - just a sharp point like a small hole punch.

Lightly tap the tube over the broken screw so the sharp end fits snugly over the screw and goes about 0.5mm into the wood.

Put the tube in a hand crank drill, put the sharp end back in the small groove around the screw that you made by tapping it, and turn the drill backwards whilst pushing lightly. The tube will grip the screw and turn it out of the hole

No wood will have been removed but the edges of the hole will have been compressed, so a drop of boiling water will swell them back and when dry, a small drop of superglue will seal the wood.

Now it's as good as new and ready for the new screw which should be lubricated with dry soap to stop the same thing happening again.
Thanks !Newbie, worth a go but cant really see how it will grab the screw, but I will definitely give it a go.
.
.
Like I said - google plug cutters
Thanks Mick I'll check that out as well but I suspect a plug cutter will be bigger than the 10mm dowel hole I have to work in, but I will give it a go, all suggestions welcome.
.
.
Re Unnscrew-ums

Unfortunately looks like they are only available in the larger sizes.
 
Flynnwood":2kt8jfjv said:
Drill a hole into the bolt/screw, tap one in and twist the lot out. If I remember correctly, success rate was over 95%. Hope that helps.
Thank you, Those snap on extractors are the nuts, I think snap on is still life time guarantee. Something like that may work but it would have to be pretty small, 10g screw is under 5mm less the thread I have less than 4mm to drill into, again I will give it a go but its in a dark hole and I have loads of the pippers to do.

I also still have the issue, why did they snap? - probably still grabbed by the epoxy glue and epoxy mat at the top of the thread. Thats why I am erring toward something that will either grab the outside and hopefully break the epoxy hold.
Or
more destructively drill around the remaining screw and repair the damaged layers somehow - Mahogany deck beam/epoxy layer/teak deck at top.

I have ordered some of these from the USA (kindly suggested by someone on a boat forum)
http://www.woodcraft.com/category/20009 ... ctors.aspx
 
zak99":25ql6ygm said:
Thanks !Newbie, worth a go but cant really see how it will grab the screw, but I will definitely give it a go.

The screw thread grabs the inside wall of the tube and locks into it.
 
iNewbie":1wxumivx said:
zak99":1wxumivx said:
Thanks !Newbie, worth a go but cant really see how it will grab the screw, but I will definitely give it a go.

The screw thread grabs the inside wall of the tube and locks into it.
I'll give it a go thank you.
 
Random thinking had another idea, a bit drastic maybe, what do you think -

To recap So what I would be left with is a snapped 10g bronze screw in a hole on a teak deck. The top of the hole is counter bored to 3/8 or 10mm.

So if I used my Trend router flat on the deck with say a 3mm straight bit and a 9.5mm or 10mm guide bush sitting in the counterbore. Should accurately go straight down the center (in theory!!!) Then plunge down the bit to the depth of the bottom of the screw. Then maybe increase the router bit size, or maybe try an easy out or some variation. Just thinking out loud, I should go to bed or to the pub, or service the getaway car !!
 

Latest posts

Back
Top