seized stainless screw, aluminum mast

[tbodine88]

My Tabernacle is aluminum. I broke a cleat. I am trying to replace it.


one stainless screw came out easily.


The other one was seized, I used a impact wrench to remove the screw.


Now my dilemma is do I reuse the screw after cleaning off the oxidation or get a new one?


should I redress the threads?


Thanks

[sailinmikeinaz]

My vote is start with a new screw. Much less aggravation and less likely to make a marginal situation into a bad one.

[SVTatia]

And don't forget yo use a anti-seizing compound when you mount it back.

[RaymondR]

New.

If you had to use a lot of force to remove the old one there is a high probability that it is already yielded and may already be more inclined to break if you need to remove it again in the future.

[Bent Bugle]

I'd replace both screws , put the old good one in the used but still good screw box, clean up the threads & apply anti-seize, also a touch of sikaflex or similar between the cleat mounting face & whatever you're affixing it to doesn't hurt...

[Rumrace]

Most bolts and screws with decent torque on them are single use. Cheap insurance to toss them out.

[Cheechako]

New screws. Often, your threads are no longer existent, just white powder. Check that and drill/tap oversize if necessary. Put lanolin or something on the new screws.

[chasmains]

Seriously look at the mating threads as mentioned above. It’s highly unlikely they are worth anything as they exist now. Aluminum is weak in shear anyway. Investigate either threaded inserts (Helicoil is a brand name.). McMaster-Carr has no-name inserts and kits. The kits will have the proper drill bit, tap and some inserts with needed insert tools.
Another method for smaller screws and bolts are rivet nuts (Rivnuts), or weld nuts which are inserted and welded into the base materials. There are other methods too.
The cool thing about inserts is that they are far stronger than the original threads. But all of them should have a corrosion-resistant thread lubricant on them.

[CDR Smith]

Originally Posted by Cheechako

New screws. Often, your threads are no longer existent, just white powder. Check that and drill/tap oversize if necessary. Put lanolin or something on the new screws.

What Cheechako said . . . Or, you might consider helicoils and bolts. That way the Loctite between the helicoil and the aluminum minimizes the galvanic action, and you have a steel bolt into a steel helicoil. Makes any future removal of the fitting much easier 'cause the helicoil stays put and you just remove the bolt.

[s/v Jedi]

For a cleat, I would use a gel medium strength thread locker instead of anti-seize or Tef gel. You don’t want that screw to loosen.

Agree with others to use new screws and clean & inspect the threads in the aluminum.

[Rumrace]

While I love thread inserts of many types I sure don’t know any which would not cause corrosion on T6 aluminum. If you had an aluminum one made from billet T6 it would only equal the mast. Despite the aluminum being the metal which will sacrifice in contact with a metal higher up nobility it’s way stronger than stainless.
If anodized it will chew up the best cutting tools made. Instinctively I use locktite on everything. It’s also a good thread design for the job keeps things working well. Unless you have real serious corrosion a little diluted alkaline, rinse and run a tap through it to clean. I’ve added behind brackets thin nylon washers to end corrosion spots.

[Manateeman]

New bolts. Drill and tap new holes 6 hole diameters away from old holes if you are looking for more strength, bend a doubler plate larger than the cleat and pop rivet it into 5200 after it’s been drilled and tapped for your new bolts.
Still concerned then TIG the plate on.
We like Tef-Gel but locktight will do just acetone wash before.
Anywhere we have to attach something that is not suppose to move, we add another thicker and larger layer of aluminum.
Manatee dance parties tend to get way out of hand as the beer kegs get opened.
That’s why I don’t drink. The crew doesn’t fit in most ambulances. My job is truck driver and bail money man.
Happy trails to you.
Captain Mark

[Rumrace]

T6 aluminum welds reduced strength of the extrusion by 40% or more. It maintains thread better than most metals on a boat. Current quality of stainless fasteners allows stretching more than ever.