Cannot tighten tiller to rudder shaft

[Lukas 0]

Hi, please does somebody tried to replace top rudder bearing on CAV 32? There is a decent play between shaft and collar and while engine is idle it makes decent rattle...

Thank you, Lukas.

[Black Panther 1,523]

Rudder will have to come off. This is done by pulling the shaft up ( leave the tiller on, even use it as a lever). When rudder and shaft removed the bearing can come out. I can't remember what sort of bearing they used but throw it away and ask Island Time where he gets his sexy super slippery ones from. You may need to take accurate measurements or find someone to do that for you. The new one should slip right in with a little dab of something to keep it in place. Replace rudder. If it is stiff remove and attack the inside of the bearing with sandpaper till it spins freely. There are no seals as it drains into the ocean.

When finished you will have a greater knowledge of how it all goes together.

The shaft is married to the rudder with two bronze keys. These may object to coming out, beat them. They can also lead to a tiny amount of slop which is unpleasant when sailing. I fixed it with an application of a hot mix of west epoxy. It locked them in and my assumption was being brittle a sharp tap would release  them. But everything worked so well I never got to find out.

[LBD 94]

Proper solution...

Take rudder and clamp to a machine shop and ask then to spread the clamp say 3mm, fit a 2mm shim in the gap and tighten up

Set up in a lathe and bore to about 4mm larger than the diameter you accurately measured.

Machine up a stainless steel sleeve about a 2mm wall thickness and slot it  just a whisker wider than the key

Clean up the keyways... and make a new good fit key.

Thoroughly clean and dry all components... oil free, and assemble the halves, and key onto the shaft using a little Loctite...

Quick dirty solution... 

Dismantle and clean all components oil free, and spread the clamp faces about 1mm.

Assemble with Loctite "quickmetal" or Devcon epoxy metal on the shaft and keyway, and only nip  lightly up the clamp. Next day or when fully cured tighten you the two halves to correct tension.

 

 

 

[Frank 131]

11 hours ago, LBD said:

Proper solution...

Take rudder and clamp to a machine shop and ask then to spread the clamp say 3mm, fit a 2mm shim in the gap and tighten up

Set up in a lathe and bore to about 4mm larger than the diameter you accurately measured.

Machine up a stainless steel sleeve about a 2mm wall thickness and slot it  just a whisker wider than the key

Clean up the keyways... and make a new good fit key.

Thoroughly clean and dry all components... oil free, and assemble the halves, and key onto the shaft using a little Loctite...

Quick dirty solution... 

Dismantle and clean all components oil free, and spread the clamp faces about 1mm.

Assemble with Loctite "quickmetal" or Devcon epoxy metal on the shaft and keyway, and only nip  lightly up the clamp. Next day or when fully cured tighten you the two halves to correct tension.

 

 

 

I would be doing the quick and dirty as LBD describes above, any of the epoxy/metal powder products such as JB weld or similar should do the trick, Chatfield engineering probably have bronze key stock and you can buy SS key stock at ANZOR in east tamaki. Then at a convenient time I would take it to a machine shop to  bush the tiller head as described.

[SloopJohnB 322]

or use a "Scottish key"

[Guest 60]

I have a similar setup except I have isolated the play not to keyway/shaft but yoke arms to tiller body as  well as elongation of holes in yoke arms and body. So I had holes oversized, with new thru bolt to match.  On retightening play was reduced  considerably. Enough to ignore slight play. Two  years later  it is back to square one.

 

[LBD 94]

When you look at it, it is actually a design fault. As the yokes from the tiller wear on  the clamp piece, the clamping force on the rudder stock reduces until it is loose and there is no clamping force on the rudder stock.. and the key is relied on as the sole positive drive mechanism.

[Island Time 1,184]

There should be no movement. Zero. The key should be a slight interference fit, when clamp is tight.  Most tiller arms are like that, and provided there is no movement at all, they will last a very long time... Any tiller arm joints with pins should be bushed, and bushes replaced when needed. Vesconite bushes are self lubricated and last incredibly well.

[Frank 131]

Vesconite is good stuff, as I understand it most engineering plastics will swell to some extent in water, Vesconite (trade name ? ) is one of the few that doesn't.

I used oil impregnated Nylon for my first DIY rudder bearings it froze the rudder rock solid in a few weeks. I vaguely recall a few  years back you could purchase a pourable graphite impregnated epoxy resin and cast perfect bearings with the rudder in situ, don't know if its still a thing.