building up boat propeller shaft

[sardine]

I need to stick weld 316 stainless 3 mm thick to a lengh of 120 mm on a 1 _1/2 " shaft, will this distort the shaft ?
It will be turned and keywayed after.

Or would it be wise to get it spray welded ? I do not want to fork out for that if possible. I've got that box of 316L that I thought I'd never use sitting there.

 

[Fazerruss]

Don't know about stick but I successfully did the same repair with tig on a ms shaft from my saw. I had to do the full circumference which may have helped reduce distortion. Shaft was about 1 inch diameter.

 

[Pete.]

Course it'll distort. Do you have a lathe with a fixed steady available for re-cutting the centre in the end?

 

[Rrunnach]

You have to be very careful when work is complete, if you upset balance of prop/shaft, you could end up knackering gearbox due to vibration.

 

[sardine]

Yes the thing will be re machined after ward, the weld would be continuous around the shaft for 120 mm of its length ( out of 600mm OAL ) it,s a keyed taper that needs to fit a prop with a 6mm bigger bore.

A new shaft is 300 quid plus machining on top, just to put it into perspective.

 

[Fazerruss]

I would go for it. If it distorts just cut a slot in the opposite side and weld up. With a bit of heat and gentle persuasion you could get it spot in in the lathe

 

[MattF]

Why not just turn down the shaft somewhat then make and fit a tapered sleeve?

 

[Rrunnach]

is job an inboard, outboard, or stern drive????

 

[Keith 66]

It will distort so you will have to weld opposite sides as you go. How long is the shaft by the way, i just bought a 5ft length of 1 1/8" 316 bar from speed alloys & it was £94 delivered.

 

[sardine]

The reason d'être is cost, I can probably get it machined for 50 quid, a new length of 50mm bar is 80 or 90 quid, and a tapered sleeve is definitely possible if welding is not.but I would guess the double height key is not ideal engineering.

Its going on a 22 " propeller driven by a hydraulic drive, not coupled to a gear box.