Anyone using stainless prop nuts? Any galling problems?

[Ron V]

Just wondering if anyone has had any galling problems using stainless prop nuts. The shaft is 15-5 PH and the nut would be 18-8, so I'm not sure if that is enough difference in chemistry and hardness to prevent it. I'm going to order some new thin nuts from McMaster to use with my SRX, and kind of hate seeing the rust on the plain zinc plated ones. But I'll keep using those if stainless isn't a good idea.

Can anyone confirm that the standard Merc shaft thread is 3/4"-16? That's what I measured it at.

[staylor]

If the 18-8 is dead soft then galling will be minimized- but it can still gall up. Usually when they say 18-8 they mean 304 that is hard enough to guarantee galling if not treated carefully with anti-seize on both male and female threads under load. I've had good luck with either neverseize or the copper based "grease" they sell for holding exhaust systems togather on cars. On my old OMCs I ran SS elastic insert thin nuts that were pretty hard and never had troubles using the copper based antiseize. Just thinking about SS on SS reminds me of trying to torque the bolts and nuts on an '80s Land and Sea jackplate that managed to seize 2 of the 4 transom bolts during install....
Doug

[HStream1]

Just wondering if anyone has had any galling problems using stainless prop nuts. The shaft is 15-5 PH and the nut would be 18-8, so I'm not sure if that is enough difference in chemistry and hardness to prevent it. I'm going to order some new thin nuts from McMaster to use with my SRX, and kind of hate seeing the rust on the plain zinc plated ones. But I'll keep using those if stainless isn't a good idea.

Can anyone confirm that the standard Merc shaft thread is 3/4"-16? That's what I measured it at.

Yes 3/4 - 16 is the correct diameter and pitch. As suggested SS to SS regardless of the difference in the grades = anti sieze. You can also use Bronze nuts.

[THE HOGG]

i HAVENT HAD ANY PROBLEMS. BEEN USING A STAINLESS NUT ON MY FATSHAFT SPORTMASTER FOR TWO YEARS. AND YES, THE SAME NUT..(i KNOW, I KNOW, LET THE BASHING BEGIN.)

[Ted Stryker]

Stainless and stainless never meet without anti-seize on My boat... That may be overkill due to My lack of finite metallurgy, but clean threads with some good "goo" on em' have no reason to gripe...

[typhoon]

My Mariner has a bronze nut, worth looking in to.

Regards, Andrew.

[Eagle One]

Believe it or not, simple dish washing detergent will prevent it from galling. Even grease or oil won't help at times but plain old dish washing liquid will almost everytime. Just put it on all the threads first..