Model Boat Mayhem - Forum

Mess Deck: General Section => Chit-Chat => Topic started by: Klunk on September 16, 2016, 04:32:46 PM

Title: Prop shaft removal
Post by: Klunk on September 16, 2016, 04:32:46 PM
I have aquired a billings Progress fishing boat in reasonable condition with one massive problem. The propshaft is completely seized. I have managed to get the inner shaft out but the bearing came with it solid on the shaft. I want to replace the outer shaft with a new m2 prop shaft but how do I get the old outer shaft out? There is not enough room to heat the tube up and to dig it out would mean destroying the rear end of the boat. Any ideas?
Title: Re: Prop shaft removal
Post by: Shipmate60 on September 16, 2016, 04:42:02 PM
Pete,
Either use a large soldering iron to get some heat into the shaft.
OR
Find a piece of brass tubing a snug fit over the shaft, file some teeth in one end and "cut" the shaft out.
I have used this method and found it does not damage the surroundings.
You will need to lubricate and frequently remove the cutter to remove swarf.


Bob
Title: Re: Prop shaft removal
Post by: Bob K on September 16, 2016, 04:47:10 PM
I recently had to replace shafts in my HMS Amazon after one developed a totally seized needle roller bearing.

First I made two thick neoprene pads to sandwich the hull, on its side, with long adjustable claps.  This to protect detail which wasn't fitted when I originally mounted the shafts.

Then, using a fine pointed diamond-coated bit, I used the trusty Rotacraft (like a Dremmel) to carefully drill around the shaft like a dentists drill.  Took out 3 mm all round the shaft, which includes the epoxy I had used to set the shafts in place.  Not too much of a mess and the hole not too large. 

Fitted two new regular 2mm shafts, set with epoxy as originally, then a bit of filler to smooth the hull profile.
Amazon runs very nicely again now, as you may have seen at Black park.
Title: Re: Prop shaft removal
Post by: john44 on September 16, 2016, 05:55:24 PM
You could try heating a rod that fits inside the prop tube and see if it transfers enough heat when
Inserted back in the tube to loosen the outer tube from the hull.


John
Title: Re: Prop shaft removal
Post by: Capt Podge on September 16, 2016, 11:30:59 PM
Just a thought - if you have access to some knitting needles, find one of a good tight fit, insert in prop tube, then grip tube with pliers and give a sharp twist. Might work... :-X

Regards,

Ray.
Title: Re: Prop shaft removal
Post by: Geoff on October 13, 2016, 01:51:39 PM
If the problem is a seized bearing and the bearing has come out why not just make a new bearing? Also as a thought if you can remove the other bearing is there room to slide a new brass tube inside the old shaft and use that as the outer casing for the new prop shaft.


Its an interesting little question with many answers


Cheers


Geoff
Title: Re: Prop shaft removal
Post by: Buccaneer on October 13, 2016, 08:06:32 PM
I have removed a couple of old prop shafts with a cordless drill. Start with a small size drill, just bigger than the shaft, and this will probably remove the bearing. Take a drill slightly larger than the inside of the prop shaft and attempt to drill it out. It will probably leap into the prop shaft a short way, possibly splitting I, and then the whole prop shaft will start to turn. give it a couple of short bursts and your prop shaft will be free so you can simply knock it out.

Not many prop shafts will resist the torque of a good cordless drill as they are mostly just knocked in and given a dose of epoxy or fibreglass at each end.

John