Propshaft replacement?

Started by Back in the Groove
9 replies 15 likes Last activity: 7 years ago
#10

Propshaft replacement?

Sounds like that will do the job nicely.
Let us know how you get on.
Good luck.

Martin555.
If it looks right it probably is.
Liked by Back in the Groove
#8

Propshaft replacement?

Hi,
If you keep the old shaft tube long enough you could also use a hair drier to get the tube hot enough to soften up the glue then you also have something to grip hold of.
Please try not to burn yourself!

Martin555.
If it looks right it probably is.
Liked by Back in the Groove
#7

Propshaft replacement?

Thanks Everyone - I will need to change the entire prop shaft, as it is less than 5mm internal diameter anyway, and seems solid brass. I plan to install a new 5mm unit.
Liked by Martin555
#5

Propshaft replacement?

Hi Bill,
I concur with Graham.
An imperial propshaft will almost certainly have a BA thread.
I would change it for a 5mm shaft. You may have to change the prop as well, or drill and tap to 5mm. To ream out the bushes you may find it easier to keep them 'in line' by knocking them out, use the old propshaft, and ream / drill both together. A small lathe helps!
When refitting the bushes use the new 5mm shaft to help keep them centred.

If push comes to shove and you do have to remove the tube a sharp tap on the end with a light tack hammer while gently twisting with Mole Grips usually breaks them loose without wrecking the hull.
Worked on my Sea Scout, same problem; rusted 3/16" shaft and worn bearings🤔
BUT I cheated🤗, I made a new 4mm shaft and bought 4mm I/D sintered phosphor-bronze bushes and Raboesch brass prop to suit😁
Hope this helps more than confuses, Cheers, Doug 😎
PS I agree warming the tube to soften the glue helps. I tried it with a 50W iron on my PTB but it couldn't cut the mustard. So I used a small, kitchen style, gas torch.
Tap tap twist and out they came. Only had to remove them cos a complete hull renovation was necessary🤔 I blogged it on this site, somewhere!!
Now it's cookin' time. C youse guys later👍
Young at heart 😉 Slightly older in other places.😊 Cheers Doug
Liked by Back in the Groove and Martin555
#3

Propshaft replacement?

I am replacing the entire prop shaft on my Patrol Torpedo Boat refurbishment. I am going to cut the shaft about 15mm from the wood and heat the remainder with a 60watt soldering iron inside the hole to soften the glue. When reasonably hot, I will gently tap it out with a drift.
I cannot promise to finish one project before starting another. I know, I tried.
Liked by Back in the Groove and RNinMunich and
#2

Propshaft replacement?

Bill,

I had a similar problem. The other issue I had, which you haven’t mentioned, but may also be an issue for you, is that my original propshaft had a 4BA thread at each end. Modern props, and engine couplings, are metric.

I replaced the inner shaft with 4mm silver steel threaded M4 to suit modern fittings. That did mean I had to make new phosphor bronze bushes, but at least I didn’t have the problem of trying to remove the brass outer tube from the hull.

Graham93
Liked by Back in the Groove and RNinMunich
#1

Propshaft replacement?

I’m refurbishing a 34” Vosper Fireboat, and as I’m stripping it, have found the propshaft outlet brass “bush” to be slightly worn. It’s a 9” brass tube, with a 3/16” (4.6mm) x 10” inner shaft. The outlet bush is worn to 5mm, and the input to 4.8mm. I’m looking for some advice please. Should I just grease it up, and carry on; ream each bush out to 5 mm, and replace the inner shaft; replace with a completely new 5mm propshaft? If replace the entire shaft, how do you remove one without damaging a wooden hull? Thanks in anticipation! Bill
Liked by Martin555

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