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JohnCenter

(Puukko) Understanding stick tang designs

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I've been comparing different puukko stink tang designs. For example a typical Lauri:

http://brisa.fi/knife-blades/lauri-pt/lauri-pt-77.html

versus a typical Polar:

http://brisa.fi/knife-blades/polar/polar-77.html

On a completed knife using the Lauri design the bevel will go all the way to the handle/bolster (no ricasso) and the plunge line is hidden inside the handle. While, on a completed knife with the Polar design there is a ricasso. I am assuming theses design choices are aesthetic (correct me if I am wrong). However, for making a knife they create differences. The Lauri style makes fitting a tight bolster much more difficult than the simple rectangular shape of the Polar.

So, if I wanted a design where there was no ricasso, but the easier rectangular tang, could I not simply make the plunge line end exactly at the bolster? Would this work? Or is there some strength/ general knife building rule I am ignoring?

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The Puukko shows a wide variation in form, however, most "Traditional" forms I have seen do not have a ricasso or plunge line.  The bevels (all 4 of them) continue into the handle.  There are a few folks on here that are true experts on the puukko form, perhaps they will chime in.

I've only made one, and I cheated by filing a small relief in the tang so that there was a little step behind the blade that the handle butted up to.  This helped cover the transition to the handle.

Edited by Brian Dougherty

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Good point on the 4 bevels (Rhomboid?). That would be another step in difficulty. Who are the puukko experts? Maybe I can message them. Is there a forum more dedicated to puukkos?

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John, when it comes down to the basics of your question, it really isn't about the blade shape or design, it's about fitting a guard or bolster over a tang. Isn't it?

Regardless of the blade shape or ricasso/no ricasso design choice (and there are reasons for a ricasso which I will get to later) the guard has to fit tightly up against shoulders of some sort. There are what I call the 2-shoulder and the 4-shoulder methods. To put it simply, the 2-S method cuts the guard slot to the dimensions of the front end of the tang and presses up against the shoulders at the spine and edge ends of the blade. The 4-S methods grinds a slight shoulder into the tang from the spine to the edge on both sides. now the tang slot can be made to fit the tang and has 4 shoulders to seat against. I do not know of any threads on this forum that show the process, but this one describes different ways to achieve it.

This thread over at the ABS forum has two really good photo pictorials on hidden tang guard fitting. That show the 4-S and the 2-S methods.

http://www.americanbladesmith.com/ipboard/index.php?/topic/2554-fitting-a-guard-–-topic-for-september-2016/

Now about the why of ricassos.......I believe the design predates the modern era (there are historical photos of rapiers and daggers with the ricasso) but it was popularized by Sheffield to speed production, precisely because it makes fitting a guard that much easier and faster. The other reason is for sharpening. It gives you somewhere to end that isn't running into the guard or bolster plate. If you "drop" the choil, you can sharpen the entire edge and not run into the plunge lines.

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Then again, for a Puukko try this.

 

Edited by Joshua States

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No experience or advice to offer, but here's a page I like to read.  https://nordiskaknivar.wordpress.com/  Puukko blades and the smiths are frequently the focus of his monthly posts.

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A design with no ricasso has two primary advantages. The first is a slight functional benefit of having cutting edge that goes all the way to the end of the handle. This is nice in some situations, but rarely matters that much. The main benefit is that you save a ton of time (in my experience, more than half of the grinding and almost three quarters of the finishing) by not having to worry about plunge cuts. Also, I like to do the final sharpening/polishing with stones and sand paper on a surface plate, and plunge cuts complicate that.

From what I can tell, the use of thick (0.25") metal bolsters is a modern one. Historic examples seem to either have all wood/antler handles or ferules made from formed sheet metal. For both of these cases, accommodating a rhombic tang is that difficult (burning/softwood wedges for wood, or some light filing for a ferrule). I typically make puukkos without bolsters as it saves a lot of hassle, is traditional, and it pulled off well is a nice look.

It's pretty hard to fit a rhombic tang into a thick metal bolster, but plenty of makers do a great job of it. You can see a lot of  good examples at the website Gerald suggested.

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I'm not sure what to say. A wealth of information shared and I definitely have a better understanding. Now for practical application!

I guess you are right Joshua. It isn't really about tang design, but about getting a correct fit regardless of design. An example of looking at something from the wrong angle on my part.

I'm familiar with the Nordiskaknivar blog. Lately it is permanently open in my browser. It is also the reason for many frustrations. The knives posted are incredibly fine made. More like jewelry than tools!

 

Aiden, for your reference to wood: Do you go for a perfect fit? Or use some type of filer for gaps? Glue mixed with saw dust? Or you mentioned soft wood? Isn't that visible?

Do you peen or is it an all glue hold (like Roselli's)?

 

 

Edited by JohnCenter

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1 hour ago, JohnCenter said:

Aiden, for your reference to wood: Do you go for a perfect fit? Or use some type of filer for gaps? Glue mixed with saw dust? Or you mentioned soft wood? Isn't that visible?

Do you peen or is it an all glue hold (like Roselli's)?

I generally go for a tight, but not spotless fit through a combination of burning, filing and broaching (both with handle broaches I made and by hammering the block the last 3/8" or so onto the tang). I always use epoxy,  but don't add any filler. The epoxy does a lot, but considering that it takes a hammer and vice to separate the press fit (and that historically these types of blades were held together with resin or nothing at all),  I wouldn't say it's just the glue. You can see more about that here: https://nordiskaknivar.wordpress.com/tag/maasepan-puukko/

As for wedges, I wrote a topic about that a few years ago here: 

There are a few pictures of one of my early puukkos, and then some other folks showed some great historic examples. If find the technique easier than just fitting the tang, and it can definitely lead to an attractive fit.

 

Edited by Aiden CC

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I was always worried about a tight fit on the tang without a guard of some sort or a pin through the handle & tang and  relying just on a glue-up. I was never really certain that such a small amount of glue would last or hold well enough, especially with a burned-in tang. Just my own pessimism. What I do now is I widen out a glue pocket in the bottom of the tang slot so the front remains tight and there is more room for glue deeper into the handle. This is a little tricky, but it works (I guess, or at least it makes me feel better)

I took a piece of 3/32" music wire from the local ACE hardware store and cut a piece about 6 inches long. Then I hammered about 3/8" of one end into a spade shape. (I'd show a picture of this, but it's already packed in a box) Now I chuck it up in my Dremel tool and slide the spade end into the tang slot. The spade end spins in a conical motion and carves out small bits from inside the handle. It also cleans any charred wood out of the tang slot so the glue has good purchase. I cannot say that this is really worth the trouble, but it seems like it should provide for more epoxy to hold the tang into the handle.

Edit: Aiden is the Puukko master. Take his advice over mine.

Edited by Joshua States

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9 hours ago, Joshua States said:

I was always worried about a tight fit on the tang without a guard of some sort or a pin through the handle & tang and  relying just on a glue-up. I was never really certain that such a small amount of glue would last or hold well enough, especially with a burned-in tang. Just my own pessimism. What I do now is I widen out a glue pocket in the bottom of the tang slot so the front remains tight and there is more room for glue deeper into the handle. This is a little tricky, but it works (I guess, or at least it makes me feel better)

The glue pocket definitely wouldn't hurt, especially in getting through the burnt wood from a burn-in to get a solid surface for epoxy to bond to. Wedges also give you a nice glue pocket (the oversize hole you drill before hand) which has clean surfaces for epoxy. I have a couple of these puukkos lying around (a wedged handle and one burn/broach fit) and since they're so quick to make for me now, I haven't felt bad about putting them through their paces. They do fine with heavy cuts, batoning, etc. I've been pretty impressed with how well the partial tang construction holds up, though it does make sense, given that this is how many knives were made for a long time.

12 hours ago, Joshua States said:

Edit: Aiden is the Puukko master. Take his advice over mine.

I'm definitely not a master, but it is the type of knife I keep coming back to, and certainly the style I've made the most of. I think about 1/3 of my knives have been puukkos.

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I've only ever done one puukko-style blade, but I love me some stick tangs and have spent a lot of time on them.

If you get the burning-in right and you use something like birch or maple for the handle, you don't NEED (though I use epoxy anyway) any additional adhesive simply because the remnant substances in the wood heat up and basically turn into tar. If you leave the blade in the handle too long after the last bit of burn, it takes a vice and hammer to separate them again. 

Go ahead, ask how I know. :lol:

Anyway, the point I think I'm getting at is: don't underestimate the inherent strength of a solid press-fit! 

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"All puukkos are knives, not all knives are puukkos."  Pekka Tuominen.  From "Collectable Knives of Finland" by Lester C. Ristinen, ISBN 0-9626838-1-4.  Worth looking at, lots of variation in regional styles.

Have you seen the, excellent, tutorial by Niko Hynninen on forging a puukko?  Niko's tutorial

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