On my 45 year old classic plastic, the tiller is attached to the rudder rod with two pieces. On top of the rudder rod is a bronze fitting that has a horizontal hole for a bolt that acts as hinge pin that works in conjunction with the bronze H shaped part that bolts on to the tiller. My question is: The hinge pin bolt has worn down over the years and there is a little too much "play" between the tiller and the rudder. I'm having a hard time finding a bronze replacement bolt. (7/16 bolt, 3 inches long but with the threads only on the last half inch) But a stainless 304 is easy to find. I've been told by the local metal shop that the difference between the 304 bolt and the silicon bronze fittings isn't great enough to cause problems. What say you?
Dissimilar metals
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Although ........................
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The chart below shows the worst case scenario. It would probably be less aggressive than this as the SS would always be losing some of its passivation due to wear, along with a few other other minutiae.
..................... you might want to check it over in about 30 - 40 years
.The chart below shows the worst case scenario. It would probably be less aggressive than this as the SS would always be losing some of its passivation due to wear, along with a few other other minutiae.
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He's got electrolyte back there for sure.
Hell, I've got electrolyte in my bunk. At least I THINK it's sea water electrolyte
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Replace with the stainless........ and keep your eye out for a bronze version.... after a while you'll realize your concerns were unwarranted. Besides, because you can inspect and change it so easily, you could but a zinc bolt in there to serve the purpose.
But if it really drives you crazy, there are a number of products you can coat the bolt with to keep it from contacting the bronze fitting.
But if it really drives you crazy, there are a number of products you can coat the bolt with to keep it from contacting the bronze fitting.
I did a search at McMaster-Carr for Bronze Bolts and the search came back with silicon bronze bolts
Here is the link if interested. There are a lot of choices.
http://www.mcmaster.com/#silicon-bronze-bolts/=pkqr92
Here is the link if interested. There are a lot of choices.
http://www.mcmaster.com/#silicon-bronze-bolts/=pkqr92
any bolt that has the proper shank length with only enough threads to hold the proper nut without excess length sticking out, has probably had the extra thread length cut off of it...
using an unmodified bolt of the correct overall length in a pivot joint such as in your situation, the shank of the bolt will not reach all the way thru both sides, and the threads will work in the outgoing side of the hole. being a bit smaller already and somewhat abrasive, over a short period of time it will get looser as it either enlarges the hole, or wears the threads down as it works in the hole....
but when you take a longer bolt that the shank can reach completely thru both sides of the hole, it will give better support on all of the moving and standing parts, with a minimum amount of wear over the years.
flat washers can be used to shim the nut or bolt head if there is too much shank sticking past the exit side, because sometimes you need to be able to tension the pivot so its not tight, but not sloppy loose either... but in almost all cases like this, the extra length of threads will stick out past the nut an inch or so and may have to be cut off to look nice and trim... a custom made bolt...
using an unmodified bolt of the correct overall length in a pivot joint such as in your situation, the shank of the bolt will not reach all the way thru both sides, and the threads will work in the outgoing side of the hole. being a bit smaller already and somewhat abrasive, over a short period of time it will get looser as it either enlarges the hole, or wears the threads down as it works in the hole....
but when you take a longer bolt that the shank can reach completely thru both sides of the hole, it will give better support on all of the moving and standing parts, with a minimum amount of wear over the years.
flat washers can be used to shim the nut or bolt head if there is too much shank sticking past the exit side, because sometimes you need to be able to tension the pivot so its not tight, but not sloppy loose either... but in almost all cases like this, the extra length of threads will stick out past the nut an inch or so and may have to be cut off to look nice and trim... a custom made bolt...
Too many failures w/ 304 over the years to use it by choice, anywhere around salt water. Why take the chance?
We also can't forget the millions of chrome plated bronze turnbuckles with SS studs in either end.....
the fails on my boat were 316,which i was advised by a metalurgist was more brittle than 304.
i like the fact my chain plates are some what less brittle than the cracked ones i removed. mebbe they will last thru an accidental landing on a breakwall..it didnt last thru an accidentally on purpose one by the drunken owner before last and subsequent salvaging and kinda refit.
i like the fact my chain plates are some what less brittle than the cracked ones i removed. mebbe they will last thru an accidental landing on a breakwall..it didnt last thru an accidentally on purpose one by the drunken owner before last and subsequent salvaging and kinda refit.
I think that if you compare these data you will be hard put to define enough difference between the stainless steel alloys to make an argument of one versus another. http://www.nealloys.com/300_series_alloy.php
I would have to think that getting one made is the best bet. You won't want threads where none were before. That will cut into the bronze but quick....right?
Thank you to all who replied. I found a 3 1/2 inch 304 SS bolt that had unthreaded (shank) that was slightly over 2 1/2 inches long. Just put a few washers on. I cut off the excess length. I put a light coat of tef-gel on the parts that came into contact with the bronze. If it gums up, I'll take it off but I figured it couldn't hurt.