tool steel application

So here's the deal- I have some antique wood planes that I'll use- I don't want to use the original 'irons' (metal scraper part) because
they are pitted & preserved for history's sake. I have cut some .125" O-1 tool steel to function as the new irons. Do I need to temper the steel? My so-called research has just left me confused. I recognize that any steel is tougher than wood- but these days modern wood plane's irons are sometimes cryogenically tempered. I've used these & it makes me think of a ceramic material in use & sharpening. I don't need the high-falutin latest super process- just something workable- that I can shave wood with & resharpen as needed. Thanks for the education...Bob
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Bob, I have been told: That a freshly hardened piece of tool steel has some very high internal stresses. If the tool is tempered, the stresses are allowed to releive somewhat. If there is no stress relief, there is a significant chance of stress cracks. Most hardening suggestions say to do the temper immediately.
I guess you need to weigh the cost of the tool vs the cost of tempering.
In my case I just wait until the kiln is down to tempering temp, reset the control, and kill it an hour later. Almost no cost. Dave
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O-1 is supplied in an annealed condition, you'll need to harden and temper your blades if you want to use them for cutting anything. You should have gotten a sheet with hardening instructions with the steel or they should be on the manufacturer's web site. O-1 is pretty easy to harden, for cutting tools, you can temper in your oven, I have used an electric fry pan for die buttons. Quench in oil, motor oil WILL work, it's smoky, do it outside. You only need to quench after hardening, after tempering, just let it cool if you're doing it in an oven. You'll probably have a time keeping your blades flat when quenching, they'll want to warp.
If you use a torch to heat the blades up for hardening, you're going to get a lot of scale, welding suppliers and knife making suppliers will have some anti-scale paste. You don't want to final sharpen before hardening, put on the bevel, though. One method of hardening is to make a plate with a handle on it, put your blade on it and heat it from the bottom to redness. Use a magnet to determine when it's hot enough, it won't stick. With thick pieces, it takes time for the crystal structure to change so those are best done in an oven by the manufacturer's directions. Thin sections can be done with a torch if you don't mind the scale cleanup. There are a lot of old-timey blacksmith receipes for tempering by color, you CAN do it that way, but since you'd only be applying the heat for a very short time, you won't be getting the full benefit of the steel. Again, it takes time for the crystal structure to change, best do it in the oven, particularly since you're going to want things hard and that will take the lower end of the tempering range. Those old-time charts were for pure carbon steel, not alloyed stuff like we have today. They work, after a fashion.
I'm sure you know that there are plane blades are available for those oldies from the wookworkers' suppliers, I'm not sure that making your own is any cheaper these days. If you're doing blades for molding planes, then that's different.
Stan
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Why make it so complicated? - set one up, sharpen it, see how it goes. THEN worry about it if needs be - lets face it, plane blades need sharpening often if you want a nice clean cut, the tempering/hardening process will just extend the time between the need for sharpening.
And if you plane blade is sharp enough, you should be able to do such a fine cut you could read print through the shaving...
(No, I aint a woodworker, my cousin is and he gave me a tutorial on the things....)
Andrew VK3BFA.
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On Sat, 12 Apr 2008 20:21:24 -0700 (PDT), with neither quill nor qualm, snipped-for-privacy@hotmail.com quickly quoth:

Did he tell you about ScarySharp(tm), where you can't wave the sharpened blade around too fast for fear of splitting atoms? ;)
The OP should look to Steve Knight or Ron Hock for blades. They've got it right. http://www.knight-toolworks.com/ (I have a stable of his planes.) http://www.hocktools.com/ (I have one of his irons in my Stanley #65-1/2 plane and love it.) Both do cryo treating nowadays.
Hayseuss Crisco, don't look at his shellac prices. They're 5x what I paid for Paddylac just short eons ago.
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The hardened steel will be brittle like glass if you don't temper it. Grind the surface clean and heat the center part of the blade until the cutting edge turns straw yellow to light blue. The rest of the blade could be dark blue, brown, purple etc.
Discarded circular saw blades are a good cheap source of steel for home-made tools. Whether it is oil or water-hardening doesn't matter for thin steel. I anneal the stuff by wrapping it in flattened tin cans and tossing it in the wood stove. Rub some Ivory soap on the steel to reduce scaling.
Jim Wilkins
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They sell replacement blades - thicker and tempered properly. Highland Hardware for one.
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1500 degrees 15 min, quench, don't allow it to go below 125-150 degrees, temper at 350F.
Wes -- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller
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Guys, I can't thank you enough. Knowledge increased quantum leaps. BTW I should have mentioned that the irons are for a molding plane, otherwise I wouldn't be going through this. Does make me wonder what our founders experienced.
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I'm cutting firewood (the Husqvarna remark, Ed) on the land of a neighbor who makes custom furniture and doors in various antique styles for the Boston market. I help him by making and sharpening tools. I think the most important thing we've learned from dissecting old woodwork to copy it is that those old immigrant cabinetmakers were very clever and found simple ways to accomplish complex-looking tasks. Perhaps their knowledge is still common in Europe but they didn't write it up in English for us here, so about all we have to learn from is their work.
You might like the tool-making books by Alexander Weygers.
Jim Wilkins
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On Thu, 17 Apr 2008 04:22:48 -0700 (PDT), Jim Wilkins
<snip>

<snip>
If you ever make it to Michigan and enjoy odd woodworking stuff, you should check out "The Shrine of the Pines". See:
http://www.shrineofthepines.com /
This guy did some pretty amazing things with old pine stumps and hand tools. Made his own glue too.
--
Leon Fisk
Grand Rapids MI/Zone 5b
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