hidden tang knives...and stainless...

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Sep 9, 2001
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428
looking back over some old posts i noticed some recommend not making a hidden tang or stick tang knife from anything that cant be differentially heat treated.

how true is that? to some extent i do understand the reasoning but really, a 4'' blade of a hunting knife shoudnt ever be used as a crowbar anyhow and shouldnt be expected to function as one.

so, is there any real problem with making a hidden tang knife from some of the super stainless's? im not talking about a tang that is 1/4'' and threaded on the end, just one that is about 1/2-3/4'' or so back into the handle.

thanks again
 
I know people that do this all the time.The main thing you have to do is make sure you leave a rounded corner at the junction from the blade shoulder to tang joint,dont make it a square corner as this will make a big stress riser and can let the knife break allot easier.
Bruce
 
how do you fit the guard nice and tight with the curved shoulders? maybe im not fully understanding what you mean though.

any pictures of what you are talking about?

thanks again
 
I'm struggling with this, too. I don't have any milling tools, so I do all the cutting with files. Terry Primos had an excellent tutorial on his website on doing a "solderless" guard (uses JB Weld instead). I don't have the link anymore, but it might help answer your question, or at least give you another technique. Basically, I think it boils down to rounding off the inside of the guard to match the rounded edges of the ricasso. It's very aggravating. I just remembered there's also some info on stress risors in one of Wayne Goddard's books, but don't remember which one. Not a lot of help, I know.
 
Here is a ruff sketch of the tang area. I think what Bruce is talking about can bee seen below. You want to radius the at the start of the tang like it is shown on the right, not sharp like on the left.

You can still get a nice tight fit with your gard and not cause any stress risers. The transition from the ricosso shoulder stays sharp. I use a 1/8 inch chainsaw file to releave that area.

Hope this makes sense.

tang1.jpg
 
7mm, thats what i was thinking it was. i just dont see how it would be as easy in #2 to make a good tight fit to the guard (as you would have to file the guard in a curve as well, i think)

just seems like it would be WAY easier to file a square cutout in a guard than a rounded one.

then again, nothing that works well is easy ;)
 
I am sure others with alot more knowhow than me will correct me if I am wrong, but here it goes.;)

I dont think that having a nice tight fit in that area is important. I don't think the gaurd really adds to a knife's strength. It is just there for, well, to protect your hand, and for looks. I think the nice tight fit is for getting a nice clean solder joint, not to add strength.

I know of one maker who will leave the acutual gaurd quite sloppy, and then solders a thin gauge piece of bronze, brass, N/S, etc. to the tang whick will hide the sloppy gaurd. The gaurd is just held on by epoxy when the final assmbly is done. That maker is Dr. JPH and he does that technique when using blued gaurds, because the heat from the soldering process will destroy the finish.

I am interested to see what the others say about this. :confused:

Hope that helps
 
Thats what I was talking about;) :p ;)

Now as for it being easier to cut square shoulders and square slot in the guard,I don't know about you guys but I can never file perfectly flat anyway.The way you do the guard for the tang is just use a small square file and roll the ends of the slot in and that way the guard will fit in snugly..

Now as for Laredo's question..Yes this can also be done,But you have to have a nice tight fit on the spacer that is being attached to the blade in front of the guard,This is easier due to the fact that the material you are using is thinner.I often set both the spacer and the guard together when I solder thus making both tight to the blade,But when using a Damascus or heat blued guard or something like this that the heat could destroy or you couldn't clean the solder off without destroying the looks of the guard the spacer should be soldered by itself and the guard epoxied on,Make sure you get plenty of epoxy in the joint as it can break loose if the knife is used while chopping (ask how I know this:eek: )This is not a good reason for a sloppy fit up with the guard.But you don't have to be as exacting as you do when you are going to solder the joint.

Remeber this ... A little more time spent on the fit of the tang with the radious is better than a customer using the knife and it breaking on them when they needed it most and them coming back and saying bad things about your knives..

Bruce
 
ok, does the stress riser idea only apply to stainless blades? or only to the hardened part of a blade?

why do you see so many O1, 1095, and 5160 blades that have the sharp angles? is it because a lot of these knives are differentially hardened?

also, how much of a round does it have to be? just enough to make it not a sharp angle?

thanks again
 
I am going to try this one more time...
The server keeps stalling and won't post my reply:confused:

Now in my opinion you should radious this junction on all knives no matter what kind of steel or heat treatment.I also see some with what looks like square corners and have to wonder about that also.The radious only has to be a small one,just enough to take the sharp corner out.
Bruce
 
My understanding has always been that ANY steel can suffer from stress risers. You can help negate this by normalizzing cycles, but any sharp corner poses a potential problem. That's why I ran the two I'mw orking on now through a flash normalzie then full normalize yesterday, andam now hardening them today(as edges have sharp cornesr, and so do pin holes drilled through, as I dno't countersink them at all to round the edge). So I normalize twice(or three times, ;probably, next go around), and then still differentially heat treat.
 
One of things I love so much about working with carbon steels is the number different characteristics that can be imparted by thermal treatments. There's just so much you can do with this stuff if you have a good handle on what's going on inside the steel.

Mine are some of the ones where you'll often see a 90 at the back of the ricasso. For clarity I refer to that area as the guard stop. To date I've not had one break in this area, even when I'm doing destructive testing. I'm only entering this discussion because quite a few pics of my knives have appeared showing the guard stop, and I can see that it might cause some confusion.

I'm guess I'm probably becoming noted for doing things that are somewhat outside the box, such as solderless guards, scale-free heat-treating of carbon steels, drilling pin and bolt holes after assembly, and so on. There are a few other things I do which I haven't documented, that might cause looks of confusion. But I do test quite a bit, so I'm not just running blindly out there.

Let me state that I am not trying to say that my way is the right way. I am not saying that people should be doing it the way I do. In fact, I would suggest that you don't do it this way if you are using air-hardening steels, or have not done enough heat-treating and testing to be confident with what you're doing. This is just the way I am doing it, and it works well for me.

Here's an old shot of where I've filed in the guard stop on a hunter. You'll notice that I've filed a shelf all the way around the ricasso. This is something else that you will occasionally hear should not be done.

finished-shoulders.jpg


Will this type of setup hold up to punishment? Here's a shot of a 10" camp knife being tested. The guard is resting inside, but right at the edge of the pipe. On this knife I did many of the things that I've seen be warned against. The guard stops are at 90, the ricasso shoulders (plunge to the stock removers) are at 90, the guard is a tight fit, etc. There is some serious stress going on here.

bendtest.jpg


Here's a shot of the same knife, and a smaller one (El Camino) which was tested to destruction. These look pretty rough. But there's not much sense in spending hours making one pretty when you know you are about to destroy it.

tests.jpg


Now, the smaller knife did break, but that was fully expected. You'll notice that the break was at the start of the clip (which was radiused by the way). You can see the transition line (where the softer steel starts) right behind the clip. There were no surprises here. It broke exactly where I expected it would. The sharpened clips are ground in the hardened steel obviously. Notice that the tang and the guard stop area is completely intact.

I believe that one reason this works so well for me is because the back of the ricasso and tang are at a tough spring temper. I also believe that the distal taper plays an important role. Of course, when you really think about it, even though these are at 90 degrees, there is still a tiny radius. Look at the edge of your files. The files don't have sharp edges. There is a tiny radius.
 
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