Cutting a 1" prop shaft

[DanTribe]

I need to shorten my one inch diameter stainless propellor tail shaft.
I hope to do it in-situ as removal is a bit of a drama.
What chance do you think I have of doing this with a hacksaw, or perhaps angle grinder?
Access is not brilliant.
Anyone had experience?

 

[Lon nan Gruagach]

Depends what part of "not brilliant" the access is. Use what ever is easiest. Your problem is not cutting it as much as cutting (or late machining) it square or at least some sort of balanced.

If you really have to do this without being able to keep the end tidy you can rebalance later by adding washers under the bolts of the coupling, a tricky trial and error process that can result in a bent shaft. So wind up the revs slowly and use a felt tip pen to mark which side is trying to spin out.

 

[GrahamM376]

If sufficient access for an angle grinder, one of these discs will go through it fast and cleanly.

https://www.amazon.co.uk/s/?ie=UTF8...hvptwo=&hvqmt=b&hvdev=c&ref=pd_sl_ucppcuzke_b

 

[Halo]

Be careful to catch any particles arising - especially if grinding. Lay out lots of dust sheets and dont spill any you capture. The reason for this is that the stainless filings you cut off will rust and burn into the grp making a right mess.
Other aspect is fire risk from grinding - dampen the dust sheets.
When I did this job I bent the propshaft. Workout exactly how you will support it whilst cutting.

 

[RichardS]

Be careful to catch any particles arising - especially if grinding. Lay out lots of dust sheets and dont spill any you capture. The reason for this is that the stainless filings you cut off will rust and burn into the grp making a right mess.

I've made that mistake when cutting steel chain on the GRP deck. Never Again! But would that happen with stainless steel? Does it rust once it's cut into filings?

Just for my future reference when I have to cut SS.

Richard

 

[Steve_N]

Yes, the 1mm cutting discs will do it no problem, I used one to shorten my 1.5" shaft in-situ head first down through the base of a cupboard. Spin the shaft and mark an accurate square line to cut to and make serveral smaller cuts on that line only as far in as the centre of the shaft i.e. don't try and cut all the way through from one side. You should end up with a nice square end - in my case it was cut accurately enough to be clamped by the Aquadrive taper clamp.

 

[rogerthebodger]

Yes, the 1mm cutting discs will do it no problem, I used one to shorten my 1.5" shaft in-situ head first down through the base of a cupboard. Spin the shaft and mark an accurate square line to cut to and make serveral smaller cuts on that line only as far in as the centre of the shaft i.e. don't try and cut all the way through from one side. You should end up with a nice square end - in my case it was cut accurately enough to be clamped by the Aquadrive taper clamp.

Or get someone to rotate the shaft while you cut and this will ensure you get a square cut.

 

[Steve_N]

Or get someone to rotate the shaft while you cut and this will ensure you get a square cut.

Personally I like my metal to be stationary when I offer up a cutting disc spinning at 11,000rpm in an akward space.

 

[vyv_cox]

I cut my 1" shaft several times when installing my Aquadrive, using a hacksaw with 18 tpi. However, it was done standing at a bench with the shaft in a vice. Trying to do it in situ would be very demanding.

I cut my new manganese bronze P-bracket with a cutting disc. It was relatively easy but again, was held firmly in a vice. It makes a lot of dust. I avoid grinding inside the boat whenever possible for this reason.

 

[Halo]

I've made that mistake when cutting steel chain on the GRP deck. Never Again! But would that happen with stainless steel? Does it rust once it's cut into filings?

Just for my future reference when I have to cut SS.

Richard

Richard
Stainless has some free iron in it . This will rust unless it is passivated The passivation process is the formation of a chromate layer which happens naturally on smooth surfaces. On filings the free iron can start to rust and this will not heal up with a chromate layer. Instead the surface iron and rust will act like a wick drawing more iron to the surface and creating more rust. So the short answer is yes.

 

[chrishelen]

I need to shorten mine by 2 inches when I install my new gearbox. Someone mentioned a hacksaw and I think this would pretty demanding, I think an angle grinder with a large disc is the way to go, cutting a groove and turning the shaft 180 and cutting again

 

[RichardS]

Richard
Stainless has some free iron in it . This will rust unless it is passivated The passivation process is the formation of a chromate layer which happens naturally on smooth surfaces. On filings the free iron can start to rust and this will not heal up with a chromate layer. Instead the surface iron and rust will act like a wick drawing more iron to the surface and creating more rust. So the short answer is yes.

Thanks. I'll remember to treat SS as I would now treat mild steel when cutting it over GRP.

Richard