geometry close to edge

samuraistuart

samuraistuart

Joined
Dec 21, 2006
Messages
3,158
I have been thinking lately (watch out!) about blending the shoulder of the secondary bevel with the primary. In other words, begin the sharpening process by establishing the edge, and then feathering that shoulder into the bevel while doing the post heat treat grind. I hope that makes sense....and I am most positive that many of you guys do that exact thing on a regular basis. This will be my first.

Any tips like that for superb slicing geometries?
 
I think I understand what you are saying?

On some thicker blades, daggers, and swords, I establish the edge with a 45 degree grind on each side. Then I shape the bevels to the pre-HT shape. After HT, I re-establish the bevels and finish up to a 400 grit belt. Then ( especially on Japanese swords) often blend the edge back into the bevel just as you describe. I do this on the slack belt or on a rotary platen ( Beaumont). The rest is taken care of in hand sanding and sharpening.

In Japanese sharpening, this is called an "apple seed" grind. Westerners often just call it a convex grind, or a Moran grind.
 
Yep....you get what I'm after. And the apple seed shape of the katana was one inspiration to do this. Not going for a "convex" grind on the primary, nor the secondary, but a smooth transition between the two. I think basically it will be a flat cutting edge...convex transition.....flat primary bevel.

I had no idea you made samurai swords! Forge? Stock removal? One of these days I would love to try a katana stock removal from W2. Would have to come up with some sort of heat treat set up, tho! First will be a stock removal tanto...a copy of a 17th century I luckily stumbled upon. I had no idea you did swords too. Man of many talents!
 
By all means you should try one. I would suggest a wakizashi first ( I greatly prefer a wakizashi to a katana). A wakizashi and tanto set is highly sellable, and a joy to own.

While it is not a long knife, a sword isn't a huge leap. From what I have seen, you have the basic skills. Feel free to PM or email me with any questions, or post a thread in Shop talk.

Forget W2...it isn't a sword steel. Try 1080 or 1070. Get as low Mn as possible. Aldo had some nice 3/4" Sq. 1080, and good 1075. Both will hamon nicely. The 3/4 forges out to a sword well.

I occasionally do stock removal, but forging at least partially shapes the steel. In some cases I forge to near finished proportions. In making a katana/wakizashi/tanto the basic shape is all you need tom forge, as the real shaping is done in shitaji-togi. after HT shiagi-togi finishes it up and brings out the hamon.

I just ordered 1000 grams of Japanese tamahagane from a smith outside of Tokyo.




As an aside ( and shameless commercialism) I am getting ready to offer a batch of ornate sterling fuchi-kashira sets in The Exchange. These will be good for swords, tanto, fancy fixed blade knives, and sgian dubh.
I have a tutorial on "designing a knife around a handle" that shows how I make these.
 
Double post...so I'll post additional info.

Stu - I have a stack of DVDs on making Japanese swords and fittings if you want to borrow them.

All but then tiniest forges can do a sword. Even though I have a 48" sword forge, I normally use a Whisper Lowboy to do full size katana. I have a 48" quench tank made from a cut off oxygen tank.
The sword is "pumped" through the forge and slowly heated up. At any one moment all but 14" is outside the forge. It is the method used by many swordsmiths...including Walter Sorrels. c Currently, I have a really neat project going. It is a titanium sword set with Ti hardware. It is a challenging task to make these.

There are probably twenty sword blades sitting around the shop and leaning against the wall by doors in the house....waiting to be finished. Guests love to come over and discover a katana and wakizashi blade, a Viking sword, or a Scottish short sword waiting for when I can do shiagi-togi leaning by the front or back door. the chairs inn the kitchen are filled with bins of blades to be worked on. It is a fun house to live in.
 
Last edited:
Here is a visual reference that may be of interest. I have posted at least one of them before in a thread discussing urasuki. Even though they directly pertain to kitchen knives and only a single sided bevel, they seem to show something similar to what you describe. I thought they were cool.

1235676837-Hamaguriba_zpsd0509bf0.jpg


1212468034-kataba_edge_4_zps0e149535.jpg
 
samuraistuart said:
I had no idea you did swords too. Man of many talents!
Click to expand...

I've come to realize that Stacy is "the most interesting man in the world". He has parallel parked a train. He can identify UFOs. He bowls overhand! He once had an awkward moment just to see what it was like. And finally, His two cents is worth $37 and change! Bladsmth doesn't always make katana, but when he does... :D[/I][/I]
 
Perrin...that's hilarious! :) Your cross sections were well received...I've seen them before. Great pics. Stacy....thanks for the DVD offer. Once I get there....I might just take you up on that. I want to improve fit/finish more before I tackle something like that. When I mentioned W2, I thought to myself, Stacy is going to say "choose a different steel". I agree with ya. Maybe 1075 one of these days!

Forgot to mention.....Tamahagane, huh? At the risk of sounding too inquisitive...how did you score tamahagane? I think I saw a little bit of it on Dictum, or WHeaven, I forget. That's pretty impressive, Stacy, that you can forge swords!!!!! I haven't forged ANYTHING yet, would love to someday.

One of my biggest question, when the time comes, would be the sori. Do you forge the waki/katana fairly straight, and allow the water quench to do it's thing? Are you forging/grinding in reverse sori and doing an oil quench? I would prefer the traditional water quench...and let the positive sori happen....but have no idea what the overall geometry should be going into the hardening process. I think all of that will come by just....doing it.
 
Last edited:
I don't forge a katana often....but when I do, I use tamahagane!


Seriously, I use a variety of steels. I occasionally do a brine quench if the steel is very low Mn and water hardening. On regular blade steels and damascus, I forge/grind in the sori and use oil for the quench. I leave a bit of extra in the spine and edge to allow for exact shaping after the quench. Also, remember that the blade is very pliable right out of quench...so while still hot from the oil, you can add or remove a bit of sori in a straightening jig or on a wooden anvil.
 
I posted some videos of Jim Crowell doing what I think you are talking about. A flat grind with a convex edge, Appleseed, Moran edge whatever. What a lot of the ABS smiths do. Didn't see a video anywhere explaining it.

Is that what you are asking about?
 
ShawBlades...yessirrreee that is exactly what I am talking about......for the most part. Pretty much. Dead on...almost. I think in all actuality that I am referring to the Moran edge. And stupid me....I've even heard of that term and knew what it was! But isn't a Moran edge convexed? As in the whole edge is a radius? This is what I did....after the 120 grit finish, I cut the edge in, about 25 degrees inclusive, on a 120 grit stone. Then I proceeded to knock off the shoulder created by the edge with 120 grit, and then blended it in with the final polishing. So the edge itself is still flat, so are the primary bevels. But the area of primary/secondary intersection has been blended, so to speak. I hope that explains it a little better.

I sliced the crap out of my fingers on that thing while polishing it. The edge isn't anywhere NEAR sharp....just a bevel. I bet it slices like a light sabre through a stormtrooper when it's done!
 
You must log in or register to reply here.
Back
Top