Oven tempering

[Dan W]

I've been dippin N dabbin with my forge for awhile now. Mostly just everyday things for our 1814 living history group, but like all beginners I have to make a couple of knives just because. My problem is:
How exactly do you place a knife in an oven for the tempering process?
Lay it on the rack? Hang it from the rack with a piece of wire around the tang? Place it in a small vise? What if its a large bowie style blade?
Any and all comments will be most appreciated.

[tompdw]

The method that I have been using is I put a 1/2 in thick steel plate in my toaster oven. I turn it on and let it get up to temp. Usually an hour. I then lay my shiny, hardened blade in the toaster oven and I watch for the color change. I am sure there other ways but this seems to work for me. Hope it helps.

[brucegodlesky]

I built a rack for the toaster oven. Looks like a Z in profile with slots on the up leg. I can temper 7 blades at once.

[son_of_bluegrass]

My first ones were just set on the oven's rack. After checking with a thermometer and see how much above the set temp the oven could get, I started putting the knives in an old dutch oven full of sand. The sand acts as a thermal mass and helps to regulate the temp.

ron

[dablacksmith]

i have just put it on the rack... same as the gunsmith i learned it from you need to leave it in there a wile tho so it all gets up to an even temp....

[matt993fod]

I just sat the knives I have made on the rack. I guess that this didnt affect the temper in any way, since the oxide film was even, and did not conform to where the knife had been sitting on the rack.

[civilwarblacksmith]

You can also place the knife on aluminum foil sheet to help protect from the rack.


Reb

The Civil War Blacksmith

[larry harley]

use 2 thermometers 1 to ck the other by
or u could use lead
ive thought abut it!!

[Rich Hale]

You could use lead for sure but most of the steels for knives are tempered for about thirty minutes at about 400f, Lead melts at 621.5f that would soften the steels I use too much to keep an edge.

[larry harley]

so u r sure hot lead wont work??
harley

[brucegodlesky]

the old gunsmiths used lead to temper springs.

[agsolder]

Lotta muy peligroso hazards, as in debilitating and/or fatal involved in handling lead, breathing lead fumes.

[larry harley]

the old gunsmiths used lead to temper springs.

thanks bruce for throwing that in there. i never want to call some one wrong but not only gun smiths but anyone that wanted to make banite in a spring or blade in the old days used hot lead guys like henery reichting scagle rudy ruana etc
and most well healed country black smith we now know we can use hot salt to do the same job
harley

[brucegodlesky]

Lead was prolly the only thing they had that would give them any amount of constant temperature.
Today, I believe we take for granted the scientific advances made in the last 200 yrs. In their day, the old time smiths, gunmakers, toolmakers were quite advanced in technology.

[larry harley]

i,m sometimes amazed at what them old times did. i dont think they knew some of the scientific reasons other then it worked or the reason that they gave it was wrong but it worked anyway:)

packing the edge of a knife is one u cant pack atoms on a forge:). They'd be all these little thermonuclear explosions on top your anvil but old timers were sure that it worked come to find out NASA has discovered that deformation under decreasing heat refines and normalizes the internal structure about the same thing as packing:)
whoda thunk it??
harley

[Glenn]

See reducing grain growth and be sure and read post #4.

[ThomasPowers]

Ahh they know that hammering steel below crystal growth temps but above dislocation climb temperatures would refine the grain at least 200 years BEFORE NASA was created; maybe not why it worked but that it did work.

[Rich Hale]

I think it was I that was asked if I was sure hot lead will not work. It really depends on what you want to do with your hardened carbon stell. If you want to bring the hardness down there are many ways to use to temper. Lead is for sure one of them. So is burning oil, temperature controlled sand or blueing salts. All will work and all have a history that can usually be traced back along ways. Methods and materials that just do not work die off. For these ways to live long lives they certainly have a background that says they work. My post was about this; Will tempering at 621f do what you want done? If it does not then the answer is of course lead will not work. For that application. For applications like others have mentions such as springs then the answer is yes it will work for that application. For a long time I have considered things like this are part of my tool box. Just as you will pick a correct screw driver for the screw you wish to turn. You will pick from what you know and have learned either by your own experience or from others. Add that knowledge to your personal tool box. Methods or procedures that you have at your disposal that best fit the task at hand. Some of this knowledge is stored internally and some in volumes. Some hand written and some the works of others. For sure some of the biggest additions to my personal tool box is material from this site. And most comes from folks like you. I read the posts to this site almost daily. And each day brings new thoughts that I either reject or commit to my future work. Thanks for you posts.

[brucegodlesky]

I wonder if old timey makers ever used them ol beehive bread ovens for tempering.