Fabricating bronze chainplates and tangs

[Nicholson58]

Look up Marine Bronze. It is a specific mix and is the only stuff likely to survive.

I changed my mains out to Gr5 titanium. The internet allows you to search for suppliers and best pricing. Don’t ever let them know it’s for a boat. I had three Ti quotes. X, 3X and 6X. The big number was from a specialty maker of boat titanium. Low was from a national metals supplier to general machine makers. Same guys will sell you marine bronze.

[OneBoatman]

A tip, should you decide to fab on your own order your flat stock "H02" Temper that would be half hard thus it will be much easier to form. Although they might even offer it at H03 (3/4 hard). There are both Silicon bronzes and Aluminum Bronzes that are marine grade and tough enough to work as chainplates. I would suggest C65500 silicon bronze or similar alloy because you should find it is quite commonly available.

[phorvati]

Wouldn't bronze chain plate have the tendency to wear out where it mates with the clevis pin, deform, or stretch?

Also below is how I bent my 304SS chainplate after polishing. Purchased raw material 2"x3/8" hot-rolled bar from mcmaster with certificate.

[Bowdrie]

Originally Posted by phorvati

Wouldn't bronze chain plate have the tendency to wear out where it mates with the clevis pin, deform, or stretch?

Not really, the bronze actually "self heals" so to speak.
The rigging pins have a little slack in the holes.
A chainplate of "hard" metal will have the pin making "point loading" in the hole.
The bronze chainplate, (after years,) might show a few thousands of "oblong", and if so, that actually removes the point loading, spreading the load to a greater circumference on the pin.
Once that happens further wear is negligible.
I've sailed on boats that were built in the '50s that had their original bronze chainplates, all was just fine.
In a previous post I told the OP that for bronze chainplates to add a little to the offset dimension.
As always, and no matter the material, angular alignment is important.

[Pauls]

Regarding the many posts suggesting castings, this is a poor idea for two reasons:

1. A casting is never as strong as wrought. The reason is that the rolling used to form bar, plate, etc alligns the grain structure of the metal with the length of the bar. Castings always have a non aligned grain structure and are always weaker. This is basic metallurgy.

2. It is not unlikely that a casting will have voids, ie bubbles inside the metal. For stressed castings, to ensure that they are void free the standard is to have them X-rayed. If you don't do this you are gambling. The cost of the x-rays and the trouble of having any that fail the x-ray recast plus the work of making the forms makes using wrought an attractive option.