What type of stainless for chainplate bolts?

[jimgolding]

I have two chainplates that were mounted with carriage bolts, bolts in which the head is smooth and round and a short portion of the shank just below the head is square. To accept these bolts, the chainplates have square holes punched in them. Apparently these types of chainplates are susceptible to cracking at the corners of the square holes.

Anyway, one of my 20+ year old chainplates did have a crack and I'm getting new ones made with round holes. So, I'll be getting hex bolts to replace the carriage bolts.

Does anyone have input on the appropriate type of stainless steel (18-8, 316, etc.) for chainplate bolts? I'm in Florida, if that matters.

Thanks in advance.

Jim

[Matthew Sebring]

What type of stainless are the chainplates being made from? I'd stick with the same alloy if possible with everything being 316 if that is an option. If you want more of a finished look than the stamped head of the hex bolt, sand/file the top of the bolt to clean off the stamped text, round the top edges somewhat and then polish all to a mirror finish.

[SV Papillon]

A metric ss pan head bolt will be the same profile as the carrige bolt with a allen socket in the head.

Jake

[Brion Toss]

Hello,
316, always the best grade of 316 you can get. If, for some awful reason, the chainplate itself is some other alloy, and you won't/can't replace it, at least your bolts will be good. No significant danger of galvanic action, as the difference in potential will be teensy.
As for head shape, as suggested either modify the bolt heads or find better-shaped ones off-the-shelf; sharp bolt heads on the outside of a hull are going to scrape someone, some day.
Fair leads,
Brion Toss