Going to attempt to make a sen tomorrow

wrote:

[to hollow the backs of Japanese irons]
Hammer. Good plane irons are forged hollow. Only the modern low-end stuff is ground hollow. This is also why "tapping out the back" is no longer recommended practice on modern irons - grind the edges down instead.
My sen is M2 HSS, ground from power hacksaw blade and otherwise un-heat-treated. The steel you're using it on is pretty soft at the time.
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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.
http://forums.dfoggknives.com/index.php?showtopicQ90
Chilla wrote:

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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
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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
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Finally finished the sen and gouge, they cut annealed spring like butter, also shaved a 50 cent piece, cut the quick off my fingers, and cut various other items.
I didn't bother to temper the items, so if I drop them they'll either chip or shatter. Who cares they work :-)
Regards Charles P.S. They sure look ugly :-)
Chilla wrote:

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To paraphrase the immortal Forrest Gump: Ugly is as ugly does. If they does, they ain't ugly. :)
You might want to draw them a little though, maybe a very dark straw, so they're not so hard they break if you really have to pull on them sometime.
They sound like ya done good.
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John Husvar wrote:

I was thinking about tempering it a little, and I might with the next ones I make.
Oh have you heard this Forrest Gumpism (have no idea where it comes from, definitely not the movie). Personally I find it a little dark.
"Life is like virginity. One prick can take it away"
Regards Charles
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Yeah, that's a bit dark alright.
A friend of mine in high school coined this daffy definition: "Virgin: A bubble on the stream of life. One prick and it's gone forever."
But this is supposed to be a family program. :)
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Cool. :)

My friend sez- "the ugly ones are the good ones"
Which steel is it again?
Maybe no tempering necessary if is, or acts like, a medium carbon steel like 4340.
http://www.panix.com/~alvinj/graph3stages.jpg
http://www.panix.com/~alvinj/graphStrength.jpg
Drawing at 212F for half and hour can increase the strength and the hardness -both- depending on which steel. BTDT with 1095. :)
Notice how 500F (for and hour) which produces dark straw is weaker?
JH's "dark straw" is, of course, done in seconds.
I don't know what the resulting difference is! :/
Industry doesn't use "skilled methods" like that, so I have no information on the results. :/
Anybody got any information on that?
Alvin in AZ
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snipped-for-privacy@XX.com wrote:

The tools were going to be made from 5160, but I had some old files laying around so it's either O1 or W2. It's definitely red short, so my best guess is that it's probably O1.
Regards Charles
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After spark testing close to 100 files (not including rasps) I've never seen one that looked even close to O1.
If you got that "hot short" part right (I don't doubt you) then it might have some Cr or V in it?
If it weren't so expensive (how much is postage to Oz?) I'd send you some "known samples". It's easy as anything when you got known samples to compare sparks to.
Tempering a re-heat treated old file in boiling water for 1/2 hour will strengthen it up quite a bit and make it slightly harder, both. No kidding. :) BTDT and read it too. ;)
Alvin in AZ
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snipped-for-privacy@XX.com wrote:

Very old files, it's probably mystery metal that only a tech analysis can determine, and at $80 a test it's not worth it for small quantities.
Postage is a royal pain to here, and vise versa, but I appreciate the offer. I'll get around to getting a selection of common knife steels some point, so don't worry about it.
I'll try the boiling water, never heard of that before. Have heard of quenching mild steel in brine for limited hardness. I'll definitely give it a go.
Thanks regards Charles
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Yep, that's a new one on me too. I always thought the boiling point was way too low to draw a temper.
Learn something new every day I guess. :)
I wonder what would happen with a cryo treat, maybe liquid nitrogen or helium temps, and then that draw would yield.
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John Husvar wrote:

Like a subzero quench like they use for hardenning and tempering stainless steel?
Charles
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Depending on the carbon content and other alloying it can actaully make the steel harder.
http:/www.panix.com/~alvinj/graph3stages.jpg
Since most files are about 1.2% carbon, interpolate the tempering line. Some files (5%?) spark-test higher than my known sample of "1.22% high carbon steel".
1095 and "1.22% carbon steel" is hard to separate by spark testing, IME.

[Yes] <--answering for both me and JH. ;)
http:/www.panix.com/~alvinj/graphCooling.jpg
That's a tricky graph to read, it starts at the lower right hand corner and goes up and to the left.
I "cold treat" all my knife blades (other than the HSS ones;) at -5F then clean in boiling water for a half hour then back in the freezer then draw 1095 (and 50100-B) at 325F for an hour.
The result is the difference between being able to file that piece with difficulty to absolutely making a file skate. Harder by about 1+1/2 points hrc. "with no loss in toughness" -ASM's Tool Steels
1095 and 50100-B (like W7 or 6195) draw at 325F. O1 draw at 350F. L6 and 8670-M draw at 275F.
A medium alloy steel like A2 and a cold treatment at -120F before the first temper can easily make a 2 point increase in hardness and "with no loss in toughness" -ASM's Tool Steels
In certain situations, the cold treatment, because of reduced retained austenite, can actually keep the part from breaking later by preventing un-tempered martesite from forming. So... in those cases, the cold treatment and higher hardness, actually increases "toughness". No kidding.
Metallurgy Theory and Practice by Dell K Allen and ASM's Tool Steel (3rd or 4th edtions) by Roberts and Cary
What I want is some graphs showing the results of the quick "blacksnmith style" temper drawing method. Know of any? :)
Alvin in AZ
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Got somewhere you could post some photos?
--
"Keep your ass behind you."

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Australopithecus scobis wrote:

I manage several Yahoo! lists so I could post them there. However I have been asked many times... "Where's your website? I wanna see your stuff!".
Okay I'll make one tonight.
Regards Charles
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Cool. :)
If you put a picture of your face on there, make sure and warn us ahead of time, ok? That goes for everbody with a personal website.
Somethings just need to be sneeked up on slow, that could otherwise be too disturbiing if seen un-expected-like. :/
Also could have children around that might see it by accident. :(
Alvin in AZ
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