Going to attempt to make a sen tomorrow

Hi Guys,
Anyone made a sen yet? I was unaware of this tool (which is basically a
draw knife for steel), but came across it when reading a borrowed book
on Japanese sword smithing.
The other type of draw knife I want to make is for scraping thin fullers.
I'm going to do a few other things as well, but I want to get the draw
knives made first :-)
Regards Charles
Reply to
Chilla
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check out Don Fogg's site (don't have the url handy). He has a tutorial there and some of us on his forum have made some.
ron
Chilla wrote:
Reply to
r payne
Cool. :)
Not being a blacksmith (just a high carbon steel metallurgy hobbist and knife-knut) first thing that popped into my head was... how to make a "metal-cutting draw knife" using a power hacksaw blade as the cutting edge.
They are too thin (and so flimsy) so some sort of thick piece of steel would be needed to hold it. 900F silver solder could be used which is the less obvious way to go about it?
Just thinking "out loud" not trying to change your plans, ok? :)
Alvin in AZ ps- just shoot me if I try to blacksmith using coke or coal ok? pps- I'll leave all that fun to you guys ;)
Reply to
alvinj
Hi Alvin,
Looks like the plans are out the window today (it's raining a bit and I can only work outside).
The idea is to use the same metal I use for the swords that I make... in theory a H&T piece of metal will be able to cut the same un-H&T alloy.
I plan to make it kinda chunky, but having a sharp edge.
What do you like to make Alvin?
Regards Charles
Reply to
Chilla
Is this the same thing that the Japanese use to hollow out the backs of wooden plane irons, chisels, etc.?
Eide
Reply to
Eide
A similar tool except that it's intended medium is sword blades.
We're not talking heavy machining, just small shavings to even out the blade.
However you can remove a lot of metal with these draw knives. You use them by pushing them into the metal, as opposed to draw filing where you pull back.
Regards Charles P.S. When will the rain stop? I know we need it, but it usually happens when I have a brain storm :-(
Eide wrote:
Reply to
Chilla
Do you know of the particulars of the tool that is used on plane irons? I realize I would make the size of the tool fit the job, just wondering mostly about blade geometry.
Eide
Reply to
Eide
Hi Eide,
Things I definitely know about the sen.
* I know what the sen looks like (well the one the swordsmith in the book uses anyway), and I can extrapolate the sizing based on the size of the swordsmiths hands (being Japanese hands they are most likely smaller than mine).
*
I know that it's made from the same metal as a sword (possibly an old sword).
Things I don't know about the sen.
* The exact dimensions * The exact alloy composition of the tool
What I intend to do.
* The sen illustrated in the book is a comparatively wide blade made from quite thin metal. I will make my sen shorter and thicker, but still having enough width to do the job. This way I only have to H&T a smaller section of metal, and I will be able to use it on the narrower sections commonly found in European blades. Having a shorter blade means I'll be able to apply more force(if necessary) than a larger blade.
Regards Charles P.S. It's just got to stop raining long enough for me to do anything :-(
Eide wrote:
Reply to
Chilla
if this works here is the link to the thread on Don Foggs' forum that shows my sen. Those are file handles on either end.
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Chilla wrote:
Reply to
r payne
I don't know about them being to thin. Mine started life as 1/8 thick 1095. I haven't measured the final thickness but it was forged on so lost some to scale and a little to grinding. It takes off steel about as fast as a file but I find it has less of a learning curve to get good with it.
ron
Reply to
r payne
Hi Ron,
The piece of metal I'll be starting out with is 6 mm (close to 1/4"), and about 50 mm wide (close to 2"). I intend to edge pack the blade, and compact the steel. H&T (almost sounds like T&A). Put some wooden scales on it (a couple of cutlers rivets) and we're done, last step sharpen and hone it.
I assume the difference being that the sen shaves off slivers and a file well... files.
Do you find that it needs to be re-sharpened on occasion, or has the edge held up?
Regards Charles
Reply to
Chilla
Just a thought, but I bet you could find a nice chunk of tool steel from an old lathe bit and use that, instead of a power hacksaw blade. I've found some large lathe bits for real cheap at local swap meets... I think a parting blade would be about perfect for a sen.
Reply to
jpolaski
What about a knife from a wood shop planer? Not sure how big you want, the small 12" Delta blades are 12 inch long, by about an inch wide. I have a hand chisel someone shaped out of a used planer knife that is about 4 inch long. If you check carefully, you might pick a part of the knife without the nicks ...
Reply to
BradK
Questions to the sen senseis:
Is a sen always straight across, or can they have cocked handles like drawknives?
Couldn't one just re-harden an old drawknife?
Why a 35 to 40 deg bevel? Wouldn't 85 to 90 degrees work better, and longer?
Is there any back-bevel on those 40 degree edges?
Inquiring minds want to know...
Reply to
Australopithecus scobis
You got a woman too huh? ;)
That sounds cool. :)
The posted DFogg thread is really cool, I like the idea of using an old file... just drill it and put some stinkin handles on it? ;)
I'm a knife knut that got to reading about steel, as it relates to knife edge holding and knife edge taking, the high carbon steel metallurgy turned out to be my favorite part. :)
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Metallurgy Theory and Practice by Dell K. Allen is by-far the best written metallugy book for studying on your own and it's cheap as dirt too.
Anyway that's what I'm into, that and working on my '75 F150. :)
Alvin in AZ ps- not raining here! ;)
Reply to
alvinj
I only had one example to go from so I don't know how the handles may be configured. Maybe you could re-harden a drawknife.
I started with 35-40 degrees. As I played with it I changed technique and bevel angles to find what works well for me. I ended with a bevel of about 70 degrees. I didn't put a back bevel on but I suppose someone could try and report if it works .
At least this is my limited experience.
Reply to
r payne
Cutler's rivets? Ick.
BTDT :/
Do -me- a favor ok? And at least once, try simple peened pins... (somehow I can't really see you not having done this tho)
Like this old-worn-out I.Wilson skinner I got from a second hand store... The tang is still covered with hammer marks. :) Iron pins were used, back when, so the baby didn't turn green and stinky etc... it's my kind of knife, simple as it can be, in every direction. I used iron again after taking it apart.
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The tang only goes back to the center pin. Made around WW1 they didn't waste high carbon steel or money back then. ;)
The lower one is a 60's(?) carbon steel Dexter done the same way. Except instead of having a tapered tang it had a modern factory style square tang that I tapered and put hickory on. The I.Wilson has beech (made in England).
I re-heat treated and cold treated both those... they are hard enough to be used as a sen. :) 66+hrc, no kidding.
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That's a power hacksaw blade, 4 of the holes were drilled with a tungsten carbide tipped "glass and tile bit" then reamed to size with an 1/8" solid carbide dremel bit. That hacksaw blade is about 65hrc and was used to saw railroad rail prob'ly 3 or 4 times, the plain-ass looking wood was a saved piece of broken "spike maul" handle (same handle as sledge hammer). So it's mostly made from railroad junk. ;)
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What I figured out is, 16 penny finishing nails are 11 gauge wire at about .122" so fit real nice into a hole drilled from the 1/8" common fractional bit. Unlike most pin material that needs reaming with a numbered bit like a #30 or #29 to get the 1/8" rod to fit.
Numbered bits used to ream fractional holes aren't that big of an investment but most nails don't size-up with drill bits like the 16d finishing nails do.
I anneal the nails, they have some work hardening in them that when removed, makes them very easy to work with.
Ok, so maybe that sizing-information is only good for the US, Canada and Mexico? :/
Alvin in AZ
Reply to
alvinj
Cool, Ron. :)
As soon as I read the cool idea about using an old file... it jumped out at me... carefully hand-grinder the edge angles wanted into the center of an old file, soften up the ends, drill pin-holes, slap on some wood?
That thick sucker may not be the best tool for all situations, others might be needed?
Alvin in AZ
Reply to
alvinj
Aw cutlers rivets are fast... and I want to do other things, at the moment.
Usually it depends on what the customer wants, if the job calls for the good ol' piece of brass rod, sure. Usually the customer hears a buzz word and says "can I have X?"... who am I to say no?
My favorite way to attach fittings is by force i.e. cross/bolster slip fit, grip slip fit, pommel slip fit then peen away... nice and tight.
Tight fittings makes large blades "sing"... you don't hear this with small blades. If the fittings are loose you just hear a "clunk", as opposed to a "piiiing".
Regards Charles P.S. Like your work :-)
snipped-for-privacy@XX.com wrote:
Reply to
Chilla
I did the rough work yesterday, but I've modified the design a little.
I made the cutting edge for small knives and type 10 Oakeshott's. One handle only, and the edge front and back.
Though I'd give it a go, and make it a tool more suitable to what I do. I was concerned about not having another handle, however I have arms like a gibbon, and am ambidextrous.
If it works cool, if not it was fun doing.
Regards Charles
snipped-for-privacy@XX.com wrote:
Reply to
Chilla

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