First hidden tang - Help needed !

[Alain M-D]

Hi everybody !

I work on my first hiddent tang knife. I make the hollow grinding this afternoon and I am verry happy with the result. (it is the first time that I am happy and not too frustrated after a grinding session... )

I would like to have your opinion and your help on some questions:

1 - When I started, I thought to make my hollow grinding wider.. (see the paper model on the picture, I have 5/8 wide instead of 3/4 or 7/8 as I wanted ) What do you think ? I have stopped there for now. I wonder whether I must widen it more? A large and eavy knife (12") would have advantage has a less wide grind (it would be less fragile?)

2 - I read many times that it was a nonsense to make narrow tang knives without making selective heat treat... My knife is in 440c and I will make the treat treat by a company... Is this quite serious if the blade have the same hardness always on the blade? Can I soften the tang with a small propane torch after the heat treat? (I can make this with carbon steel, but for stainless? Do I have to heat the tang until it become blue? Is it possible with propane torch ?)

3- I wanted to make my guard immediately, but I thought that I would have to clean and put the final finish one the blade after the heat treat. If the guard have a good fit (press fit) before the heat treat, there are chances that it is loose after the final finish ? But... If I make the gard after, I will not be able to modify and correct the shoulder of the tang with files...
Before or after ???

Thanks for your hel guys !

Alain M-D

 

[Greg Covington]

Great looking blade!

The blade looks great the way it is. If the geometry looks good now...leave it alone. Bringing it up higher might thin it out too much.

I think it was Bob Engnath that said it was possible to selective draw 440C. If you do....keep that edge in water and then go up to blue or purple.

I would personally wait to make the guard....you dont get much scaling from 440C in the heat treat but you will have to remove the discoloration and that might affect your fit.

Greg Covington

 

[Mike Hull]

Looks OK to me. One thing you might want to do in the future, grind the top bevel first, leave it a little thick at the point. The top bevel will be below the point, but that's OK. As you grind the main bevel, it will bring the bevel up to the point.
I'm not trying to tell you what to do, only recommending an easier way.
Edited to add; I have made many stick tang knives from 440C. It will work fine. It will lose some temper in the tang area as you solder the guard. Just make sure to wrap a damp washcloth around the blade, so any heat wont migrate to the cutting edge.

 

[Alain M-D]

Thanks Greg and Mike !

I would personally wait to make the guard....

ok, it is as I thought, I will wait...

grind the top bevel first

Really? I believed the opposite, I will try this the next time...

I'm not trying to tell you what to do

You can ! All the advise are welcomes

I have made many stick tang knives from 440C. It will work fine. It will lose some temper in the tang area as you solder the guard.

I do not think to solder the guard.. I rather thought to use the solderess guard technique of Terry Primos (with JB weld) and make a mortised tang handle.
http://www.primosknives.com/articles/solderless_guards/guardtut1.htm

I imagine that even if I do not softened the tang, that can nevertheless make an acceptable knife? (ok, this knife will not be a pry bar, but in any ways a knife is made to be a pry bar ?)

Alain M-D

 

[primos]

Alain M-D,
If you do the mortised tang, you won't want to do it exactly the way I did in the mortised tangs tutorial.

• Leave the tang the same thickness rather than tapering the sides like I do. You'll be assembling the handle differently from the way I do in the tutorial.
• Drill the pin/bolt holes prior to heat-treating. Chamfer the holes a bit before heat-treating.
• Don't bond the handle slabs together prior to assembly as I do in the tutorial. Fit and epoxy one slab and let it cure. This is why I said don't taper sides of the tang like I do. Oh, when you are milling out the slots to create the mortise joint, oversize them a couple of thousandths to make room for epoxy.
• Drill using your pre-drilled holes as a pilot, then attach the second slab.

With regards to drawing back the tang and ricasso:

I do mostly edge quenches which leave a tough, springy ricasso and tang. You aren't going to have that luxury with you 440C. On the occasions where I do a full-quench and want to draw back the tang, here's what I do. I "assume" you can do this with "some" degree of success with the 440C. I'm pretty sure you aren't going to get the tang dead soft. The high alloy air-hardening steels are not my area of expertise.

First off, ignore the strange look of the blade below. I put a test edge on every knife right after tempering and before doing the final handrubbed finish and assembly of the knife. The one below has just passed all the tests. The discoloration on the blade is the oxides from the tempering process.

You'll notice that I hold the blade with my bare hands right in front of the ricasso shoulders. This keeps me completely in tune with the temperature. There is no way in the world that I'm going to screw up the temper in the blade this way. When the heat starts to become a bit uncomfortable to my fingers, I'm still a long way from being anywhere near a temp that will adversly affect the temper in the blade.

Once it starts to become uncomfortable, I ease the blade tip down into a big bucket of water, stopping at the ricasso shoulders, or what you stock removal guys call the plunge. This does more than just keep my fingers comfortable. It stops the heat from traveling into the blade and forces it back up into the ricasso/tang area where it belongs. Once it's nice and cool, I lift the blade out and start working the tang with the torch again.

When using a torch, don't hold the flame in one area. "Paint" with the flame. Keep it moving. Don't just work one side. Hit all sides of the tang, top, bottom, left, and right. This takes time. A real hot flame and a quick change to blue is not going to be what you want. You want to see the colors gradually form -- straw, dark straw, vermillion (a reddish color), peacock (purple), and blue.

If it jumps to blue, you haven't effected much change. You are just getting some quick surface feedback. I've never timed it, but it probably takes me about 15 minutes or more to go from clean steel to blue. Take it nice and slow.

Once to blue is not enough.I generally do this three times, which seems to be a magic knifemaker's number for some reason. Now, like I said, the high alloy steels aren't my cup of tea, so I hope I'm not steering you wrong.

 

[Alain M-D]

Hi Terry !

Thank you very much for your advice (and pict !)
For the hiden tang: For the majority it is what I thought to doing, except for the tapering tang part. I have make a small tapering of the tang to facilitate the insertion of the guard. But I do not think that will be a big problem, I should be able to glue the scales nevertheless...

About drawing back the tang:

>>Once to blue is not enough.I generally do this three times,

Do you remove the blue (sanding) before redoing it again ? (I suppose that yes, if not, that would be hard see the color after)

>>Once it starts to become uncomfortable

It is a question which I put myself since I started in knifemaking: which can be the temperature of the blade when it becomes "uncomfortable for the fingers"? And when it burns the fingers (leaves small scar) there is a danger to break the temper or that occur only when the blade changes color ?

I did not work yet with stainless, I wonder which is the temperature of the tempering for 440c or ATS 34 ? (temperature not to be exceeded when I grind after heat treat ?)

Thanks !

Alain M-D

 

[Mike Hull]

440C is usually tempered at 400 degrees F. ATS34 can be either 400, or 900+ degrees F. It would depend on the heat treater.
As a rule, I grind heat treated knives bare handed, and don't overheat them. Gotta watch the buffing too, the temperature can get high real fast.
Your hands will start to get real uncomfortable at about 125 degrees F, so you can see, you will have a lot of leeway. It is the edge, and point that will overheat the quickest. Make a pass, and dunk. If you have a variable speed grinder, use it at slow speed. If not, don't linger on any one spot long.