Chainplate Replacement

[sabray]

Thanks for the suggestions. Thought I should post some results. I started with the intermediates as the 1x 19 was showing signs. The old chainplates were 1/4" x 2 1/2". I am replacing them with 3/8 x 2 1/2" 316 S.S. Although I think Bronze may have been the better choice. I bored the holes in a single pass with a normal drill bit. Used lots of water as suggested. 1 Drill bit has done all the holes. I resharpened about every third hole. That was too easy. Years ago I spent a fotune with cobolt tips, stepped the drilling and used words well words.
So now I'm working on my polishing. I wet sanded with 120 then 220. For buffing I started with a sisal wheel and black compound and then finished with a spiral cotton wheel and green compound. Its pretty good but I wish I could get more of the surface imperfections out. Any pointers on polishing? I have the 1x19 made up with sta-loks. Hopefully March will be kinder and I can wrap this part of the job up. You can see the crevice corrosion in the old chainplate. Although not as bad as some glad I pulled them.

[Stillraining]

Very nice...now ya got me wondering...

[sabray]

Sorry. Thats how this started too. I wondered then worried and now Im throwing away more pieces of my investment. I got caught on another boat where the owner in midst of a nasty Nor easter revealed the steering linkage was suspect . that led to some real unpleasant wondering. I replaced my steering cables this year too. I did it 3 years ago with Amsteel instead of cable. I was curious how it was holding up and the best way to get a full picture was to pull it. I figured if it was good its a spare if it aint I need to make another change. It was fine its a good spare and now Im not wondering.
Hows that mast replacement going?

[Stillraining]

Well were getting there slow but sure...Thanks for asking!..

[s/v Jedi]

Sabray,

The chainplate looks ready to drop it off for electro-polishing. Your eyes will fall out of your head when you pick them up again. Remember that it is the polishing that passivates them for long life.

Also, if you have the Fein Multi-master tool, get the polishing foot for it. I got one at Ace hardware and it works great after you're done with the wheel. You use it with the same compounds as for the wheel. But even then, electro polishing is far superior.

cheers,
Nick.

[sabray]

I have now replaced all but the aft lower chainplates. Most of the plates after 30 years looked okay a few had crevice corosion that was enough that it warranred replacement. Most of the bolts looked okay buat several were really bad. The boat had no bedding plates. Which I think is significant as sealing the working joint without them is near impossable. The new chain plates have wonder board bedding plates that were not cinched home. In a week ot 2 I will draw down on them to press thew compound firmly against the plate. The bedding plates are also beveled on th underside to promote the compression of compound. This bolt is ugly. Now for the continous journey of bedding old hardware. On the transom I used the old chainplate as a backer replacing the design of just a bolt head through the transom.

[Christian Van H]

Just a small bit of info. Although water works as a coolant when drilling Stainless, CONDENSED MILK works a thousand times better. One thing you need to avoid when drilling stainless...do not stop cutting with the bit if at all possible. The bit can actually harden the stainless if it heats the surface without cutting, and then you'll need a cobalt bit for sure. BTW, I have drilled 5/8" holes in 3/8" 316 SS with a Harbor Freight Ti coated drill bit...A BUNCH OF HOLES. Just use the condensed milk and keep it flowing.

[sabray]

Not sure which brand drill bitI used but they were probably stock x. 2 bits did all the drilling 1 at 5/8 and 1 at 1/2" both would do about 3 holes before I resharpened. I used 1/2 gallon container of water and just kept a steady flow. 1/2 gallon was usually plenty for each hole. Thanks again for all the suggestions.

[White Feather]

I broke a backstay chainplate. Took it to a local fabricator and picked up a new 1/2 thick one. Cost= $80. It had 8 holes and about a 30 degree bend. I did other things and went on saining after puting the new one on. I tried drilling 1/2 inch stainless once. Never again. Leave that to the expirenced Machinist.