Where on Earth do you find these parts?!

[Cheechako]

I don't know if you can still have bronze castings made these days, but I had one of those cast years ago. Far better than fabricated stainless I think.... especially if welded.
But, that doesn't look too tough. Bend some SS flat bar and weld a donut of SS into the bend. SS on SS is not good though, galling is a problem, but with some clearance and the water probably ok.
Upon further thought: That pic doesn't appear to have much gap or clearance though for the fabricated piece.. It appears they screwed up design wise and left it for the next owner to figure out.

[MCOS]

Originally Posted by aj676

There isn't actually a part....that's the problem. They're completely missing. The only part there is the pintle. =(
Am I getting my terms correct? See above photo. The part we need would attach to the rudder and fit onto that 1.5" diameter post. (pintle?)

Your terminology is correct. My understanding of the problem was not. You need a grundgon to fit your existing pintle. This may be a problem spot for the boat you have as the photo of the original posting is definitely a fabricated piece. See if the owner of that boat would consider letting you "borrow" the piece for reference while your fabricator makes you up a copy. Or take careful and detailed measurements, possibly make a fiberglass or plaster cast of both sides of the piece for a fabricator to replicate. Stainless is actually much easier to weld than steel so any decent welding shop should be able to weld the three pieces of flat stock. The receiver for the pintle would have to be machined on a lathe. To get the proper clearance and angle when assembled I would pay a mobile welder to do the final fitting on site. Most marinas have contacts for mobile welders who will come to the job site.

[notiesbob]

May sound a bit crazy, but - can you not take a half mold off the pintel, rudder, etc. like a dentist does for a crown? Boat builders create female molds off male plugs. You would have to stabilize the rudder relative to the pintel. Epoxy & chop would work. Then take it to machinist. Could this work?

[aj676]

Interesting and good ideas.

The original pic was just one we found online searching for a similar piece. I'll pass along the info and see if that helps spark some solutions on our end. Sure is nice putting a bunch of brains together to come up with options and ideas.

[uncle stinkybob]

Originally Posted by aj676

There isn't actually a part....that's the problem. They're completely missing. The only part there is the pintle. =(
Am I getting my terms correct? See above photo. The part we need would attach to the rudder and fit onto that 1.5" diameter post. (pintle?)

So one is missing from one hull? I would say remove the remaining and have a duplicate made or up grade both, matching. I would not run two different gudgeon's.

[aj676]

Both are missing. Therein lies the problem. Grr

[Jim Cate]

Re the issue of stainless/stainless bearings galling one another:

A fairly common practice is to use a bit of cutless bearing material between rudder post and the cup bearing in the shoe. This not only provides relief from galling, but allows a small degree of misalignment without dire consequences.

Jim

[uncle stinkybob]

Originally Posted by aj676

Both are missing. Therein lies the problem. Grr

that kinda sucks. What Jim sayed about stainless to stainless. It will gall, you should use bronze or maybe marlon for a bearing surface between.

[Offshore1960]

I was facing a similar situation this spring, and made a new gudgeon out of bronze. First I made a wood pattern, then faired and painted it. Then cast a new gudgeon in magenese bronze. Then machined it for the pin that goes up inside the rudder. My boat is a bristol 40, little bit different but the same general idea.





Hope these photos go thru if not send me an e mail and I can send you some pics

[Offshore1960]

More pics

[Cheechako]

Yep, that's what I did too. So evidently bronze foundry's can still be found?! However, the OP's pictures looks like he has maybe 3/8-1/2" clearance... not good. (post #12)

[DeepFrz]

Is the boat designed by John Simpson from the Vancouver BC area? Have you tried to contact him? He probably would still have drawings and specifications of the part.

Marine design, stock plans and services in Vancouver, BC

[UNCIVILIZED]

Originally Posted by Cheechako

Yep, that's what I did too. So evidently bronze foundry's can still be found?! However, the OP's pictures looks like he has maybe 3/8-1/2" clearance... not good. (post #12)

You can still have parts custom cast at foundry's www.PortTownsendFoundry.com
The trick is in getting the mold right. Which is where the original part, or a mockup part is real handy.

If you're confident of your skills, you can build a mockup, sometimes even simply gluing wooden bits together. But the angles & alignment of everything have to be perfect. Including those on the surfaces which the part will attach to, along with the positions & angles of any fastener holes, etc.

[Offshore1960]

Yes there are foundry's that still do bronze castings.

New England Castings up in Maine, newenglandcastings.com

and Bristol Bronze in Tiverton Rhode Island.

Both do custom castings for the boatbuilding and restoration communities, and will do one off pieces.

[Offshore1960]

The two methods used for bronze casting are sand casting and the lost wax process. Generally sand casting is done on larger pieces and lost wax process on smaller parts. Bristol Bronze does all their small blocks in the lost wax process.

The difference being fastener holes can be cast in the lost wax process but not in sand casting. On something like a gudgeon that would be done in a sand casting, and any holes would have to be bored or machined afterwards.

When making a pattern its important to be sure it fits correctly, you can add fairing compound as needed and then sand and shape to fit. Also its good to paint any patterns with a gloss enamel paint which will help the pattern release from the sand mold more easily when setting up for the pour.