Tempering A 1095 File Knife?

[Anvil_Fire777]

Hi,
I need a little help tempering my knife made from a 1095 file. I've seen unfinished knives with nice blue temper colour along the spine, heading down towards the edge is a purple leading into a brown to grey and full hardness on the cutting edge.

I think that this temper method will work for knife but i have no idea how to use do it? Please, how do you temper a knife?

[bigfootnampa]

The many answers to your question are extremely complex. Please read and STUDY the stickies on heat treating and then do a search for more info on areas that you are interested in or confused about. Afterwards repost what you still don't grasp as there are REAL experts here.

Full hard is NOT a good edge in 1095 IMO. Straw to dark straw would be my most common ideal temper color (for 1095).

[MetalMuncher]

I agree. You should do some reading. Not to be mean or anything, but reading is very helpful.

Quench (you might want to edge quench) and do a few tempering cycles (in the oven or other controlled apparatus) at 175 C (light to dark straw).

About the spine being blue: Once quenched and tempered, fill a tray with water and place the edge of the knife (half inch or more) into the water. Then proceed to differentially temper the edge from the spine by gently heating the spine until the colors run blue. This can be done with a blow-torch, or a large piece of glowing hot metal.

Those colors are oxides. The dark blue indicates a softer portion of the blade, while straw color indicates a rather hard portion.

These methods have worked well for me. However, everyone has their own preferences. Let us know how it goes!

Cheers

P.S-Read, it is very helpful ;)

[MattBower]

First, not to get sidetracked too much, but how do you know your file was made of 1095?

Second, how did you harden it? Or did you grind it cold and preserve the original HT?

Third, how big is the knife and what sort of work is it intended to do? Full hard 1095 is too brittle for a knife, in my view. Tempered to straw may be OK for some applications, but it's likely to be too brittle and chippy for larger blades that may see some impact.

[son_of_bluegrass]

I have a few knives made from 1095 (store bought) that I tempered to 325 F in an oven. That leave is pretty near full hard and they work just fine for cutting (I've never left one untempered). So long as they aren't used for prying that level of hardness works just fine.

As to the original question, you can use a torch on the spine and watch the colors quenching the blade when the color approaches the edge. It takes a lot of care and practice to do that well.

ron

[MattBower]

I have a few knives made from 1095 (store bought) that I tempered to 325 F in an oven. That leave is pretty near full hard and they work just fine for cutting (I've never left one untempered). So long as they aren't used for prying that level of hardness works just fine.

As to the original question, you can use a torch on the spine and watch the colors quenching the blade when the color approaches the edge. It takes a lot of care and practice to do that well.

ron

The difficult part about this is that there are so many unknowns. Without knowing the hardness of these blades, or whether you got them full hard in the first place, how big they are or what you use them for, it's hard to know whether your results will transfer to someone else who may do things a little differently.