[Public-List] Rudder Shoe Project Progress.......... Comments from Mike Lehman please
crufone at comcast.net
Sat Sep 29 09:49:27 PDT 2012
It looks like the mould for making the patterns will pick up the indentations of where the holes are drilled. Do you think the patterns will transfer these markings as well? Once the castings are made these small indentations would be an excellent reference for those wanting to drill their holes in the same place. Also it looks like the pintle hole in the original shoe from Mike Lehman is smaller than the normal 1/2" pintle. Do you think that was intentional so that it could be drilled out on site and adjusted in position to fit a particular boats needs? Maybe Mike has some comments about that as well.
If what you have from Mike is an original which represents all the parts made for the Whitby Alberg 30 then if you can set up a jig to drill at precisely the same angle, this would be of major benefit to most end users. The four holes for the athwart ships screws and the one for the longitudinal bolt at the back end are much less critical. I would be concerned for most end users trying to hand drill the pintle hole and ruining the casting by having the hole in the wrong place or angle. I for one plan to increase the size of the pintle to either 9/16" or 5/8" if the material present allows. Or perhaps better yet use the std. 1/2" pintle and bore the pintle hole larger to fit in a replaceable bushing as our current circumnavigator has done, with very lasting results.
Anyway, if you were to jig and drill the hole (even if were undersize) using the original as a guide, it would then be much simpler for end users to "get it right". Increasing the size of a correctly drilled hole either by drilling or reaming is much easier than starting with a blank and guessing.
I assume that the pintle hole is most critical. When the shoe is ultimately mounted to the boat some minor adjustment to the fibreglass keel portion most likely will need to be done. In fact some might reduce the size of the keel portion slightly so that the shoe could be attached using an Epoxy mush to obtain a custom mating fit.
To make these parts using sand casting, especially using fine facing sand, should be just fine. The boats lines are the major artwork here, not the rudder shoe.
Thank you for your concerted effort in our behalf. Having this method worked out and a good moulds for patterns archived will mean that these parts would always be available in the future. So good of you to be thinking of our future needs.
----- Original Message -----
From: "Peter McEvoy" <peter.t.mcevoy at gmail.com>
To: public-list at lists.alberg30.org
Sent: Monday, September 17, 2012 10:55:37 PM
Subject: [Public-List] Rudder Shoe Project Progress
Pete McEvoy here with an update on my progress casting the new rudder
shoes. It has been slow going- my apologies- but I've been busy with other
boat projects, jobs, life etc. I've been savoring this project though, and
it is coming along well. I've now got a two-part plaster mold made of an
original, unused rudder shoe (provided courtesy of Mike Lehman) and a few
copies of said original, cast in Hydrocal white. Hydrocal white is a hard
plaster with virtually zero shrinkage. The purpose of this is to have
inexpensive, accurate copies of the original.
I've uploaded photos of the moldmaking process so you guys can see how the
mold was made. It is a simple two-part mold. Feel free to ask any questions
if you'd like to know more about this. You can find the photos here:
.Anyhow, the exciting news is that within the next two weeks we should be
casting a test batch of 4-6 rudder shoes. We will be doing sand casting,
which will keep costs way down. So *right now, I am looking for folks
interested in having one of the shoes from this first batch*.The shoes will
come out of the casting with no holes drilled, and no pintle hole drilled.
That means you will have to do that part yourself. Let me know if you'd
prefer a pre-drilled pintle hole and I'll go ahead and do that. Right now
I'm more focused on keeping costs down for you all which means a bit more
The cost should be less than $100 at the most, and could be significantly
cheaper. I'm not factoring in my own time here since this is a fun project,
and the cost will mostly be based off the price of bronze and propane for
running the furnace. Are there any interested parties? First come, first
Here's the link to the mold photos:
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