Cutting stainless steel

[Steve_N]

In the course of installing an Aquadrive I need to cut my 1.5" diameter SS shaft, in situ, to avoid either lifting the engine or dropping the rudder. I have reasonable access to wield either an angle grinder (I bought some thin SS cutting discs) or a hacksaw. However, I'm scared of using the grinder: all those flying sparks and the tinder-dry sawdust and wood shavings that have lying waiting under the floorboards since she was built years ago..

So my question is do I have a chance with a hacksaw or will it just work harden and become impossible? Are there special blades and fluids, and am I looking at a few hours, a few days or indeed a few weeks hard labour?
Thanks in advance,
Steve

 

[Superflid]

Tungsten carbide hacksaw blade. Looks more like a file but does the job nicely.

Something like this http://www.permagrit.com/system/index.html

 

[Gordonmc]

A seized coupling meant I had to do the same job last winter. The position of the shaft in relation to the frames meant a hacksaw wasn't an option, so I bought half a dozen diamond edged discs for my angle grinder.
I covered all wood in the vicinity of the cut with a fire blanket borrowed from the kitchen and hung dampened canvas around the working area. The prep, including getting a big fire extinguisher to hand, took about an hour. The cutting took about 45 seconds!
The discs don't create showers of sparks and I only used one. The only problem was I didn't rotate the shaft as I was cutting so the burr had to be filed clean before the shaft could by withdrawn through the stuffing box.

 

[AndrewB]

Did this myself once with an ordinary hack-saw. Expect several hours of really hard work - I'd prefer to spend time preparing things properly and using the grinder!

As an aside, we bought an adjustible life-raft cradle at LIBS this year, which came with a stainless steel strap secured with a large padlock to deter thieves. The instructions said adjust the strap to the required length with a hacksaw. SWMBO, who wanted to get on with the job but does not know one end of a hacksaw from the other, simply snipped through the steel strap with an old pair of kitchen scissors! I couldn't believe it, but actually it was easy, even without first flexing the steel. So much for security.

 

[Steve_N]

Thanks for all the advice. I may have already have a tungsten-carbide hacksaw blade, bought to cut ceramic tiles - I'll look it out and make a test. I'm tending towards the grinder and diamond disc though. I hadn't realised that it may not shower sparks like mild steel and normal disc does, so with lots of wet towels and a hose at the ready this seems like the way to go..

 

[Porthandbuoy]

The hacksaw should do it. Contrary to popular belief st/st is really quite soft, it's when it becomes work hardened that it's a bitch to cut. Don't go too fast, "simply" keep the blade cutting, and it should go through no bother.

 

[john_morris_uk]

Thanks for the post guys. I am about to do the same job for the same reason and like a numpty hadn't thought of my angle grinder!

 

[mainmarine]

Hi
The knack of cutting stainless steel with a hacksaw or drilling it, is to do it very slowly, as it is heat that work hardens the metal. I cut the end off my keel pivot bolt 1"dia in about half an hour with a normal hacksaw blade 32TPI
Regards
Malc

 

[winchservicing]

Just a thought!

Are there any seals that could be damaged by the heat you generate while cutting the shaft with a grinder?

 

[Steve_N]

Good thought, but I should be OK. I'll need to cut here, a fair way from anything of that nature:

I'd better make sure I stop before I get to that exhaust hose though!

 

[Anonymous]

You're not going to get much throw on the hacksaw so it will be a bit of a pain. Can you pack round some dampened material (e.g. old cloth, disposable overalls, or something like that) around the area to keep any sparks from the angle grinder from straying?

 

[Superflid]

On the subject of angle grinders, I've juct bought 2 (cheapo type) from screwfix direct. Clearance sale at the mo and they're £4.69! Didn't really need them, but 2 for a tenner. Seem reasonably well built.
Only really worth it if you're ordering other items due to postage.

 

[SlowlyButSurely]

I couldn't possibly recommend this method to anyone else but when I did the same job on my boat I used a hacksaw pressed against the shaft with the engine running in gear turning the shaft at tickover speed. Very neat job it made too, in about 15 minutes.

 

[machurley22]

Fine piece of lateral thinking.

Dave

 

[supermalc]

I've just made a stainless steel shaft for my boat, and cut it with a hacksaw as my friends power hacksaw (bandsaw type) would not touch it. It did need a new blade, although still cut mild steel ok.

With easy access in the vice, it did make me pant getting through the middle of the 1" shaft, but it was relatively easy. A new fine toothed new blade was used, and I took my time.

Just as an aside. I have tried and failed several times to light a fire with an angle grinder. Cloth is the easiest to start smouldering. Try it (in a safe place of course) Now an oxy-acetalyne torch is a different matter.

 

[Avocet]

Screwfix also sell electrical reciprocating saws for about the £35 mark. Get a few blades and if you've got power there, you could combine the convenience of an angle grinder with the safety of a hacksaw. Get an adjustable speed one and keep the speed low. Also, RS sell cans of cutting and tapping fluid. This is a spray-on brown greasy yuk that helps lubricate (and cool) the blade. Also really useful for drilling metal.

 

[VicMallows]

Why not recommend it?... sounds the perfect way to me ... as long as you've made sure the shaft won't fall out if afloat! I remember cutting an axle shaft at school in order to make a hole -punch.....took 25mins on the reciprocating saw.

Vic

 

[cameocrew]

Solution to cutting SS shafting= Hacksaw 18-24TPI+Treflux cutting fluid
(dont run shaft with engine unless you want to end up armless)

 

[Anonymous]

[ QUOTE ]
Solution to cutting SS shafting= Hacksaw 18-24TPI+Treflux cutting fluid
(dont run shaft with engine unless you want to end up armless)

[/ QUOTE ]I don't see why - obviously you'd make up some sort of tool-holder. It's no different from parting a bar on a centre lathe; I thought it was a brilliant idea.

 

[fireball]

As long as you are careful and can run the shaft slowly enough .... saves a lot of arm ache and would give a good cut with no burrs on the edge .... sounds excellent to me ...

Hows about attaching a varispeed electric drill to the prop end of the shaft if you can't run the engine slowly enough (or can't run the engine) .... would need at least two of you to do the job ... I'd use a sanding plate gaffer taped on to the prop - might cause a few vibrations though - depends how good your bearing is... oh - forgot - AND the boat to be out of the water (which is why it is harder to run the engine cos you got to get water to it etc etc ....)