Tiller slips on rudder post

[Steve Laume]

The single set screw approach will work under normal conditions. It will only fail at the worst possible time. This would most likely be in high winds with a rocky shore or very expensive boats nearby.

If the key way was stressed enough to cause problems how is a set screw going to hold up?

If the bronze cap is the problem it could be filled with braze and refiled to accept the key. This just doesn't seem like an area where improvisation would be acceptable, Steve.

[bamabratsche]

Well, this has all gotten me rethinking my "if it ain't broke" approach. I will say that I have sailed the boat pretty hard over the past two years and have never had any slippage or other issues whatsoever. But Steve's point that a failure would only happen at the worst time is probably true, and it's hard to imagine something more problematic than losing control of the rudder.

On the other hand, it seems like a beefy set screw (or bolt in this case) with a deep-enough indentation on the shaft would amount to about the same thing. But I am not an engineer, so perhaps I will reinvestigate the key size issue. Looks like McMaster-Carr sells stainless key stock in various sizes, which I also could not find anywhere locally back when I was looking. I don't remember what sizes I was trying, but one fit very loosely with a lot of play, and the next size up would not go in at all.

Having had to drill out a couple of stainless steel wood screws when rebedding the toe- and rub-rails, I seriously question how easy it would be to file down one side of a tiny stainless steel key to a uniform level, though.

[Steve Laume]

You could pick up a couple of regular steel keys at a hardware store to test for fit. They are cheap and easily available. Once you determine the right size you could go ahead and order a stainless one.

I have cleaned up keys any number of times and slightly reducing the size would use the same method. All it takes is a belt sander and a can of cold water. If you have a stationary machine just get started but if it is a portable you might want to clamp it upside down in a vise. Hold the key on the moving belt and cool in the can of water as often as necessary. Go slow and check the fit often.

If you are worried about sanding off your finger tips, you could hold the key with vise grips or attach it to something bigger with double stick tape.

You might want to order two keys, just in case you sand off too much and it is still too thin, Steve.

[nscotia]

There is no key way in the rudder post or the rudder head. I don't want to remove the rudder.
If I used a dremel I would have to do both the rudder post and the rudder head. And they would have to line up just right. When I take the boat up to Nova scotia this summer, there is a metal working shop right next to my storage place. I might ask them to do the work. I'll bet they could knock it out pretty fast.

[bamabratsche]

So to follow up on this, I wrestled the cap off the rudder post yesterday and took another look at the keyway. For anyone who may need to know in the future, the key size on a Typhoon is 3/16" square by about 1 1/4" long, although I did have to file down one side slightly to get it to fit into the keyway.

My question for the knowledgeable folks here is this--after determining the proper size key I drove over to Fawcett's to see if they had key stock in stainless steel. All they had was brass, and the person I talked to there said that keys should always be a softer metal than the shaft they fit into, the logic being that if something jams or there is an accident, it's better for the key to get messed up rather than the shaft because it's much easier to replace a key. He said this is standard practice for propellor shafts and things like that (the good ol' Nissan 3.5hp 2-stroke uses a shear pin so I don't know if this is true or not).

This seems like sound advice to me, especially given that the rudder post cap is bronze, so not exactly a hard metal itself. However, I'm also worried about corrosion between dissimilar metals (i.e. stainless steel rudder post and brass key). I went ahead and used the brass one, coating everything with a generous helping of Tef-Gel (which also made it possible to get the cap on and off without any tools), but would like to hear whether this is indeed the norm, or if the guy was just trying to sell me what they had in stock.

Also, going back to the OP's question, I found this old thread that concluded that at some point Cape Dory stopped using keys and just used set screws instead, with mixed results. So the OP's setup may indeed be the original factory one, if not the ideal one.

http://www.capedory.org/board/viewtopic ... rudder+key

[Maine_Buzzard]

Freshwater, I might go with a handy brass one and check it every few years. Saltwater, and right where the water can pump up the ruddershaft, I would prefer to put bronze or stainless in.

Yes, the soft part failing and all, but that logic tends to go with high speed rotational use, i.e. the prop shaft...

Order a bronze key to fit and knock it down as needed, then never worry. You'll crack the fitting before shearing the keyway.

[bamabratsche]

That makes sense to me, but I haven't been able to find bronze key stock anywhere online. Seems like the choices are generally mild steel, brass, and very occasionally stainless. I think for now I will probably stick with the brass and Tef-Gel arrangement, and check on it every year until I have a better idea of whether it's going to be a problem. If it turns into a problem maybe I can get a machine shop to make one in bronze at some point. I wonder what Cape Dory originally used?

[Jim1945]

I took off my rudder fitting for the first and all I had was a set screw but there was a slot for a key in both the fitting and the rudder post. I'll be installing a key and the set screw to hold the fitting in place.

[Jim Davis]

I would try a propeller shop for the key stock. Bronze keys are used on the shaft at the prop.

also
http://store.hamiltonmarine.com/browse. ... 16922.html

http://www.deepblueyachtsupply.com/shaf ... /prop-nuts