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View Full Version : What's the best way to deal with a screw that snaps off in the mast?



Concordia 33
01-14-2013, 09:55 AM
1. Try to drill out the remaining screw with a twist drill

2. Remove screw with a hollow drill bit and bung the hole.

Any thoughts or other suggestions?

Draketail
01-14-2013, 10:17 AM
I expect option #2 is the one you'll have to use. Option #1 will be difficult to accomplish. Because the metal screw is harder than the wooden mast the drill bit will continually want to follow the easy path in the wood. Might as well just accept it and use the hollow bit....

Chip Chester
01-14-2013, 12:41 PM
Well, how large is the screw? Diameter, and length. Brass, stainless, other? How far down in the hole is it? How meaty is the mast around it? Is it bedded in, or just a dry screw run into a hole? And did it snap off when you were driving it in, or has it been there 30 years? This is a case of better details=better answers.

A Dremel plunge router setup with a end mill can successfully peck away at brass woodscrews, if chips are removed often. (Keep the rpm's down, and the end mill chucked up short.) The same attempt with stainless would likely fail due to work-hardening. Time-intensive, so only worthwhile for small numbers.

Chip

Concordia 33
01-14-2013, 01:55 PM
Well, how large is the screw? Diameter, and length. Brass, stainless, other? How far down in the hole is it? How meaty is the mast around it? Is it bedded in, or just a dry screw run into a hole? And did it snap off when you were driving it in, or has it been there 30 years? This is a case of better details=better answers.

A Dremel plunge router setup with a end mill can successfully peck away at brass woodscrews, if chips are removed often. (Keep the rpm's down, and the end mill chucked up short.) The same attempt with stainless would likely fail due to work-hardening. Time-intensive, so only worthwhile for small numbers.

Chip


2 1/2" bronze - I'd guess its about a #4 gauge It broke off about 1" into the wood when I tried to withdraw it. It may even have broken from when it was originally set. Probably been there for 50 years.

Lewisboater
01-14-2013, 02:04 PM
Option #1 will turn into an over-sized option #2 so you might as well go with that to start. Hollow mast or solid?...not that it matters very much, you'll still have to go the same route. Still... you could just leave it in there, bung the hole and put another screw an inch up or down... but that's up to you.

Concordia 33
01-14-2013, 03:59 PM
Option #1 will turn into an over-sized option #2 so you might as well go with that to start. Hollow mast or solid?...not that it matters very much, you'll still have to go the same route. Still... you could just leave it in there, bung the hole and put another screw an inch up or down... but that's up to you.

Hollow mast. Cannot do option 2 as the mast track already has holes in it and the screws need to line up.

Lewisboater
01-14-2013, 04:07 PM
quote...option 2. Remove screw with a hollow drill bit and bung the hole.
You already suggested option 2 yourself... how can you not do it now? My suggestion was option 3. Also... nothing stopping you from drilling and counter sinking an additional hole in the mast track.

Concordia 33
01-22-2013, 11:50 AM
I have been able to extract all the damaged screws. Some using easy-outs and some using hollow drill bits.

Were I needed to drill with a hollow bit the hole is now too large for the screw that needs to replace it. Some are in visible places and will need to be bunged and a new tap hole drilled while others are behind the mast track and invisible. For those I can either bung or fill with Flexpoxy then tap a new hole for the screw.

Any thoughts about the flexpoxy vs a bung?

Also for the bungs, if I am putting a new screw in the same place, can the bung be any size or will it split if it is too small? I assume the surrounding wood contains the bung so that there is no difference between a screw in a bung and a screw in the surrounding wood, but I was not sure about this.

Thanks