Heat Treatment

[J_SAMa]

I am now certain that my old spokeshave blade had its temper taken out. I could just buy a new one but isn't this a perfect excuse to start messing about with some fire .

First of all, how do I find out the type of steel? It was made in the late 19th/early 20th century. Is it safe to assume that it's oil hardened (O1)? What would happen if I hardened say W1 in oil?

Then comes the equipment. I have not a blow torch but a barbecue pit, and also an oven which can br used for tempering. What shoud I use for measuring the temperature when tempering? An oven thermometer or infrared thermometer? I have neither so still have to buy one of them.

And lastly, I understand that steel always warps/bends to a certain extent during the quenching process. Will this warp/bend be so much that the tangs of the spokeshave blades won't even fit the body anymore?

Sam

 

[Spindle]

Hi

I'm not sure you have the equipment to get the steel to a high enough temperature to harden it - you need to get it red hot, around 850 degrees, and keep it there for about five minutes in the case of a spokeshave blade before quenching. I don't think you'll notice any difference in it's properties whether you quench in oil or water.
I'd temper it on a bed of dry sand in a steel container on the barbeque and determine the temperature from the tempering colours.
I think you'll be OK regarding distortion provided you ensure even heating and quenching but there's only one way to find out for sure.

Regards Mick

 

[Cheshirechappie]

Not impossible, but without some decent equipment, such as a muffle furnace with accurate temperature monitoring, not easy.

Firstly, trying to reharden an already heat-treated piece is a non-starter. You need to anneal first, by bringing to bright red heat, soaking for a minute or two, and then allowing to cool VERY slowly.

Then harden right out. Heat to about the colour of cooked carrots, and quench. Oil is probably safest - the slower quench will result in less risk of distortion - though water will do at a pinch (not ideal if the steel is low-alloy O1 rather than a straight carbon 'cast steel', but you'll probably get away with it), and then temper to about light straw (about 220 Centigrade).

There may be easier ways. A bit of Ebaying may bring forth some better examples, with or without wooden bits. Wooden spokeshaves are relatively cheap and plentiful. Alternatively, Bristol Design used to supply new spokeshave irons, and may still do so, so an email enquiry to them may bring forth some joy.

 

[AndyT]

There may be easier ways. A bit of Ebaying may bring forth some better examples, with or without wooden bits. Wooden spokeshaves are relatively cheap and plentiful. Alternatively, Bristol Design used to supply new spokeshave irons, and may still do so, so an email enquiry to them may bring forth some joy.

They still have them and even travisher irons. You'd need to phone them, not email.