hardening

[naughtyboy]

planning on making some bits on lathe i bought.
going to start simply with some punches etc using bolts, offcuts of rd stock whilst im learning how to use it.

how do i harden them after so dont just mushroom ends first time i use them?

cheers

 

[London Wrought Iron]

Heat up your bits until they are red hot, then cool them in engine oil.
I think waste engine oil would do the trick too.

 

[Llama]

You will have to either use tool steel, or case hardening. You can't get mild steel that hard with heat treatment alone.

 

[steve.h]

Hi, I am not sure what rd stock is, but frommy experience with o1 tool steel you heat it to non magnetic heat, yello/orange colour and quench it in oil or water, this does leave the steel very hard but britle so you need to then heat it in the oven at around the 200 deg C mark for an hour or two depending on the thickness of the steel. your best choice for a search on it would be "quenching steel" normaly a blacksmith topic.
HTH
Steve.

 

[Llama]

I would guess it means round stock?

 

[steve.h]

DOH, I was thinking of some term for a special steel, from what I have read youcant harden mild steel anyway, has to be carbon/tool steel etc.

 

[reedx]

Silver steel is good for making punches. It will need hardening and tempering before use.
Colin

 

[hareng]

01 is silver steel otherwise known as guage plate in flat.

 

[outofthefire]

Hi, I am not sure what rd stock is, but frommy experience with o1 tool steel you heat it to non magnetic heat, yello/orange colour and quench it in oil or water, this does leave the steel very hard but britle so you need to then heat it in the oven at around the 200 deg C mark for an hour or two depending on the thickness of the steel. your best choice for a search on it would be "quenching steel" normaly a blacksmith topic.
HTH
Steve.

This methods all right for knives but I wouldn't do a chisel or punch like this, 200 degrees is a bit low it wants to be up around 280 degrees or a purple colour.

I'd heat up the piece to cherry red (or when it looses its magnetism) quench the sharp end about an inch or so in oil, quickly clean the face with some emery paper so its shiny then watch the heat creep back towards the face once its the right colour drop the whole thing in your oil and leave it there.

 

[steve.h]

Yeah, I expect outofthefire is right, I did do it the same way for my punches, butthats because I didnt know any better, they all work fine though, I think it is all in a round about way. I didnt think silver steel was the same as o1 tool steel, but again I dont know that much so may well be wrong.
I made my punches out of old sds breaker bars that came with my old 6kg sds drill, they are pretty good for making punches etc.