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View Full Version : Removing electrolysed bronze screws?



ihrig
07-11-2001, 06:34 PM
I just had my 43 year old boat at Baja Naval
boatyard last week. The planks were loose
at the transom, so I asked for a carpenter to
refasten them. The teak plugs were removed,
and the screw heads twisted right off.

Baja Naval made a sister frame which got
epoxied to the original transom frame and
the planks were drilled and screwed.

I talked to my dad after the fact and he told
me to look for a special drill bit that looks
like a tube and drills around the screw.
Anyone know where to get such a thing? I
could have avoided the sister frame and extra
holes in my planks.
a tube

ihrig
07-11-2001, 07:52 PM
http://www.taunton.com/fw/features/tools/66screwextractor.htm

Anyone know what a roll-pin is?

Ed Harrow
07-11-2001, 08:23 PM
Well if that ain't the cat's pajamas. What a clever idea. Who'd a thunk it.

There are hollow drill bits advertised in the back of our sponsor's magazine. I've heard it said they're not hard to make.

Roll pins are used to hold bits onto shafts, and the like. As mentioned in the article any hardware where store worth a hoot will have them (Note this probably leaves out Home Despot).

Also, an idea suggested by one or more, Concordia I'm pretty certain, to remove intact but free rotating screws is to get one of the "Wedging" type of slotted screw holding screw drivers. They work a treat for this particular problem.

Bob Cleek
07-11-2001, 09:47 PM
If you are refastening, it's often easier to just leave the old ones there and sink another fastener someplace else, no?

dasboat
07-11-2001, 11:00 PM
Actually the sister frame is a good idea on a 40 year old boat.Fresh wood for fasteners couldn't hoit.
The screw removers you asked about can also be gotten at McFeelys.I have sevsral and use them frequently.they are overpriced but very useful.
After I remove the old fastener I drill a larger hole and epoxy/dowel the hole before refastening.
Dasboat

Rich VanValkenburg
07-11-2001, 11:38 PM
I bought a set at the WoodenBoat Show. It'll handle sizes from 6 to 14, based on the roll-pin idea, with several teeth ground in.
They're called Unscrew-Ums, and the name on the set is T & L Tools, from Connecticut. 860-464-9485. Not exactly cheap at $35, but I became possessed when I saw it.

holzbt
07-12-2001, 07:24 AM
You can make your own unscrewums for about $.08 apiece. Buy the correct dia. roll pin and a saw file at the hardware store, file in some teeth that cut counterclockwise and have fun. It should take about 2 minutes to make and you can sharpen them yourself when they get dull.

TomRobb
07-12-2001, 08:37 AM
Yah, the toothed roll pin thing. I saw a tool guy peddling them for what seemed like a lot of money for what was there. Looked closely... hot-damn, it was an ordinary roll pin w/ saw teeth filed on one end. Cute idea. Roll yer own http://media5.hypernet.com/~dick/ubb/biggrin.gif

Scott Rosen
07-12-2001, 01:36 PM
Dasboat,

Does it concern you that you're fastening into endgrain?

dasboat
07-12-2001, 11:08 PM
Scott,good question.I thought about that when I was going to refasten several years ago.I didn't want to go up in screw size due to the small frame size in the old girl and the fact that she had been once before refastened.Before first trying it on the boat I fastened some scrap,pulled the fasteners,drilled,epoxied and pluged and then put it under water for a couple of weeks.The results were interesting.The fasteners set nicely and I could not break the joint or cause it to work loose w/o considerable effort,using forces not likely to occur normaly.When the joint did begin to fail,it failed at the frame/plank intersection with the screw hole enlarging at the frame.I could see no evidence of the threads loosening in the plank.
I drilled the same size hole as the original,epoxied in the plug,then drilled exactly as I would if setting new stuff.Seems like there is just enough dowel to clean up the sides of the hole and provide a fresh surface for the threads.I also use this method in non structural areas like refastening stainless rub rails
I survey every two years and so far(11yrs)so good.
I feel kinda foolish not having said more in my previous post.Thanks for bringing it up.
Dasboat

[This message has been edited by dasboat (edited 07-12-2001).]

ihrig
07-13-2001, 01:23 AM
Dasboat,

Well the boat is teak planked and I think the transome frame is also teak, though the ribs are something darker. At this point I accept the sister, can't do much about it now, and the job is done. Time to do some sailing with the new sails.

Karl

pwilling
07-18-2001, 09:23 PM
I missed this thread when it was current -- if I can visualize this thing, it is a set of roll pins maybe 3/8" dia and up? with teeth filed into em?

holzbt
07-18-2001, 10:16 PM
pwilling-
The inside dia. of the roll pin should be the same or slightly smaller than the outside dia. of the shank of the screws that you are trying to remove. The counter clockwise cutting is to grab the shank and unscrew it.(If you get lucky the screw will unscrew itself fairly quickly.)

TomRobb
07-19-2001, 12:09 PM
Or you'll get a hole the size of the outside of the roll-pin, either fill it or use a rather larger diameter screw, and get on with your life http://media5.hypernet.com/~dick/ubb/biggrin.gif

[This message has been edited by TomRobb (edited 07-19-2001).]

[This message has been edited by TomRobb (edited 07-19-2001).]

pwilling
07-19-2001, 12:34 PM
Ahh that helps -- also looking at FW drawing. I dont know why it hit my funny bone, but I wish busted screws were the only thing I had to worry about keeping me from getting on with my life!! But I AM going to make a set of those puppies TODAY.