Hardening and tempering

[LuptonM]

I've decided I might make a go at making a O1 dovetail chisel during the Christmas break. Although not as skilled as our Derek, as long as it cuts I'll be happy.

However I am unsure of the heating processes involved. As far as I understand one must harden and then temper (several times?)

A furnace is usually used as a means of hardening steel till its no longer magnetic. However the average man does not posses a furnace. I do have an open fire at home which gets used during the winter months, so maybe this might be some use?

Anyone actually done this and willing to digress on the details?

 

[CHJ]

You will need a good mixed gas hearth or a blown charcoal one to get enough constant heat I think.
Seem to remember Philly using a cake tin or similar full of charcoal at one time.

 

[woodpig]

Lumpwood Charcoal fed by a hot air gun or hair drier will get it hot enough to harden, conventional oven for tempering although you may want to buy a decent oven thermometer as they are supposed to be more accurate.

 

[Racers]

Hi,

I use the barbeque and a vacume on blow to harden O1 steel and some warm oil in a metal container to quench, there will be flames :shock:
When you clean the steel after hardening you can use the oven and the colour chart above the temper your blade.
Here is some shots of me making a 1 1/4" paring chisel.

Pete

 

[condeesteso]

That's a cracking chisel! You can be my secret Santa if you like (I'm assuming you like the odd hand-drill??)
How did you forge the tang??
And "there will be flames"... I enjoyed that =D>

 

[jimi43]

There don't have to be flames...I use cold vegetable oil from the COOP (cheapest)....

You need to bring the steel to a temperature of 780-800 degrees C for 1 hour every inch thick...so about 15 minutes will do...but it should be constant at that temperature for that time to get the best results...

I do mine in an enamel kiln but charcoal being blown should be hot enough....

It's hot by the way....

Plunged into oil....smoke only....

Another one...

It goes black....

Temper in oven heated to 250 degrees and then switched off...allow to go cold naturally....

Hone bevel (grind this when soft before hardening to correct angle)

Seemed to work ok....

Saves all that faffing around with the BBQ!

Jim

 

[yetloh]

Is that really in your domestic oven, Jim. Don't thinK I could get away with that. Nice lived in workshop; don't you just hate all those yank showpieces the size of a car showroom and just as clean.

Jim

 

[LuptonM]

Is there anything you guys can't do?

It would be interested to see if any of you have gone further ie. laminating blades, clay hardening, Damascus, sockets ect . I have a thing for socket chisels - don't know why

Maybe one day, I'll have mad skills and me able to make a socket chisel (western style) but with a white paper laminated blade (think lie nielsen meets Japanese) Can't believe no ones done it yet !

 

[Fat ferret]

How did you forge the tang?? =D>

Was wondering that myself. Might make a chisel too.

 

[Racers]

Hi, Chaps

The bolster is a separate piece of steel with a square hole filled in, then hammered down on to the tapered tang.
It’s a tricky thing to get right, harder than shaping the blade, some people have recommended heating it to red heat and hammering it on to get a better fit.

You could also do a bolster like my fishtail chisel

Pete

 

[Harbo]

I have an old chisel where the maker had used a largish Hex nut!

Rod