Propeller shaft for hammers?

[Smeden gegen]

Can a propeller shaft be used for making hammers? I have found an old shaft from somewhere in the 60's or 70's, thickness of 51mm and length of about 3 meters, weight estimate roughly 150 kg, a distinguishing feature is that the shaft itself is nice and sliver with a lathed finish, but other metal parts have surface rusted

[ThomasPowers]

How good a hammer it would make is depending on what alloy it is made from.  As hundreds of different manufacturers used various alloys "propeller shaft" doesn't identify it very specifically.  A good way to test it would be to saw a thin round off the end and heat it above critical and quench in water and wearing PPE try to break it.  If it's easy to break it will make a good hammer with proper heat treatment.

The nonrusting is a concern as most plated steel can be quite toxic in the forge.  If it is a stainless alloy it would probably need rather fancy heat treating to make a good hammer rather than simple blacksmith's methods.

Do you know if it was for salt water or freshwater use?

[Smeden gegen]

Salt water use, my grandad who put it in our barn salvaged it from a burned up ocean faring boat

[ThomasPowers]

Have you spark tested it?  Any idea of it's age? (If it predates stainless steel; that narrows things down a bit.)

[Smeden gegen]

60's-70's, no spark test done

[ThomasPowers]

So try the simple spark test and see if you have enough carbon in the alloy for heat treating a hammer.

[Smeden gegen]

I'm thinking of forging the little round "steel cookie" into a ~10-15mm bar and breaking it in a vise, two of them, one quenched in heated oil, one in cold water

Would it be smart to let the steel "burn off" some toxins by holding it in fire, if it's even possible? 

[ThomasPowers]

You mean: trying to burn off plating?  Do you breathe? 

If it's plated the two methods of dealing with it I know of is to 1: have it professionally unplated (and let them deal with the hazardous waste!) or 2: have a large and sturdy lathe remove it by going under it into the unplated metal.

[Frazer]

I agree, the whole point is to identify if there is a surface treatment before putting it in the forge. One thing I would try to determine whether the shaft has been surface treated is to grind into the shaft and try to rust the material both inside and outside your grind. Vinegar or salt water will accelerate the rusting process. If everything oxidizes (both inside and outside the grind) then the shaft has probably just resisted rust. But if everything else besides the shaft has rusted then this is unlikely.  If the outer surface layer bubbles (generally indicates a zinc based coating) and/or doesn't rust but the inner material does then it's plated. If there are bubbles this plating can be removed by immersion of the part in a weak acid (white vinegar for example) until the bubbling stops. If neither rusts, then the shaft is probably stainless steel.

Most modern (in my opinion 60s isn't modern) rotary shafts, if plated at all, are nickel plated rather than zinc plated and I don't know if vinegar will remove a nickel like it will zinc.

This isn't a fool proof test, and I would follow ThomasPowers' methods if possible or if the test is inconclusive, but this may give you a better idea of what you have (especially since you will effectively be doing a spark test at the same time). It's also less dangerous than just trying to burn off any potential coating and hoping that you get far enough away for long enough... just my thoughts.

 

[Smeden gegen]

I did the spark test, it came out with orange sparks with alot of air between em, i sort of saw a more grey tone in the stock, and as you can see, even a fairly strong Metabo w850 with a rhodius disc barely fazes this son of a gun, it's TOUGH

[BeaverNZ]

Its probably stainless steel if non magnetic it could be in the 300 series of stainless but prop shafts are often Duplex stainless which i cant remember if it is magnetic or not but google will tell you

[Frazer]

Chrome-moly (SAE 41XX, sorry i don't know how to write a generic series of steels for EU specifications. Something like ##CrMo#) is pretty tough stuff and is commonly used for shafts... But that's a big old piece of chrome-moly..  If it's not that it could be stainless steel.

Of course I could be totally wrong, this is just my guess from half a world away...

Edit: Magnetism test is a good idea, didn't think of that.

Edited July 6, 2020 by Frazer

[Smeden gegen]

Alright boys, i did a test of magnetism test, quite a weak magnetism, but it was there

[ThomasPowers]

Stainless.

[Smeden gegen]

So, chuck it in the forge or let it sit? 

[ThomasPowers]

The Austenitic stainless steel are not magnetic; and are more corrosion resistant, the Ferritic stainless steels are magnetic and are lower in corrosion resistance. However work hardening some Austenitic stainless steels will change some of it to Ferritic and so make them weakly magnetic. (There are also the martensitic stainless steels and the duplex stainless steels as well.)

So given the end use: salt water and weak magnetic attraction  I would *guess* it is an Austenitic Stainless and so will not be heat treatable to make a good hammer.

Sorry

[Smeden gegen]

Well, i guess it's 1045 time

[ThomasPowers]

Any good truck axles around there?  Here in the USA Axles below 1 3/8" OD forging stock are  often 1050, and often 1541H above.

[Smeden gegen]

Not really availible to my knowledge, i'll have to check, but as i said, i can get 1045 for reasonable prizes