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 :-)
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
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 ;)
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?
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
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
P.S. When will the rain stop? I know we need it, but it usually
happens when I have a brain storm :-(
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
* I know that it's made from the same metal as a sword (possibly an old
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.
P.S. It's just got to stop raining long enough for me to do anything :-(
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.
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
Do you find that it needs to be re-sharpened on occasion, or has the
edge held up?
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.
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 ...
Questions to the sen senseis:
Is a sen always straight across, or can they have cocked handles like
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
Is there any back-bevel on those 40 degree edges?
Inquiring minds want to know...
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. :)
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
Anyway that's what I'm into, that and working on my '75 F150. :)
Alvin in AZ
ps- not raining here! ;)
I only had one example to go from so I don't know how the handles may be
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.
Cutler's rivets? Ick.
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.
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.
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. ;)
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
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
That thick sucker may not be the best tool for all situations,
others might be needed?
Alvin in AZ
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".
P.S. Like your work :-)
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.