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The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.
I need to remove the boom end casting to replace the mainsheet tang...very long and sad story - don't ask...
The casting is held in place by two #8 (or #10) SS pan head philips screws. They do not budge a bit. Whether they are locked in place by a marine adhesive, the salts, or galvanic corrosion it does not matter...they don't budge...
SO - I'm thinking of drilling them a bit and using a screw extractor, or filing down two opposing sides to create flat surfaces and using vice grips.
Has anyone dealt with this and have any advice to offer?
Drill the heads off. Don't try to save the holes the corrosion has compromised the integrity of the threads. Use new screws in a different location and us some kind of corrosion inhibiter.
Before drilling them out which is a PITA, soak them in PB Blaster, more than a day is not too long to let it work itself in. Try to back them out after the soaking. If that doesn't work, apply heat to them using a soldering iron. The heat will cause the screw to expand a bit potentially loosening up any corrosion holding it together, it'll also loosen anything like Loctite that might have been applied. If neither of those work, that's when I'd start thinking about drilling / filing, etc. I've never had much luck with screw extractors in small hardware.
If you have an impact drill that delivers ~1,200 BPM, try that.
If the impact method doesn't prevail, then drilling out the screws may be your only option. I started a recent thread here that discusses how I accomplished this. A TRUE cobalt drill bit (at medium speed) and cutting oil was the formula that worked for me.
Tef Gel seems to be the goto product for preventing galvanic corrosion. While expensive, you can purchase a 20cc syringe for ~$15.
My screws were the same way, Would not move with a regular screwdriver but I have a impact screwdriver that easily removed the screws. If you own a boat you should have one of these. Cheaper alternative to the electric impact guns. Simply hit the end with a hammer.http://www.harborfreight.com/impact-screwdriver-set-with-case-37530.html
When I had this problem it was solved by cutting off screw heads, then punching the threads through with a nail punch. I worked long and hard on other methods to no avail. Cutting off heads and punching through the threads only took a few minutes. Used larger sized screws on replacement end.
Notice: The advice given on this site is based upon individual or quoted experience, yours may differ. The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.