Date: Wed Nov 21, 2001 11:57 am
In the course of my chain plate project, I found that one of the four screws that holds down the square plate on the deck at my port main chain plate is broken off in the deck. Could anybody suggest the best means of extracting it?

Date: Wed Nov 21, 2001 12:12 pm

The "correct" way is to drill a hole in the screw and then use a screw
extractor to turn it out. You could also use a dremel type tool and cut a
notch in it and then use a screwdriver to remove it. When they fail, keep
increasing the drill size and drill it out to the threads and then use an
awl or some kind of pick to work out the remaining material.

Date: Wed Nov 21, 2001 12:22 pm

I appreciate your prompt response. This screw is fairly small in diameter.

Do I need to use a reverse drill to prevent the screw from burrowing in 
further?

Date: Wed Nov 21, 2001 12:27 pm

The extractors have a reverse thread. The idea of a reverse drill sounds
good but I've never seen one. For small screws, I had almost no success with
extractors. Most of the time I've drilled them out and if necessary, filled
the hole and redrilled, inserted a helicoil or found a new location for the
replacement screw.

Date: Sun Nov 25, 2001 11:19 pm
After unsuccessfully attempting to eat away the remnants of the screw with a small drill in my dremel tool, I switched paradigms, loading a cutting wheel. I cut a groove in the top of the screw and was able to easily remove it using a small blade screwdriver. Ah the simple pleasures in life!!! For once in a while my endeavours were fairly quickly rewarded. Date: Mon Nov 26, 2001 8:17 am
As I recall the very small size screws that hold those square plates in place permit little corrosive action before the tops break off. Likely the only way to remove them is to use a small tool similar to a dental tool and slowly extract it by cutting around the diameter and then use a small needle nose plier to remove it turning it as you would a screw. Next select a slightly larger screw to replace it with so there is more metal for the salt water to work on, or use a sealant to keep the plate in place.