Heat Treating Railroad Spike Knives

Discussion in 'Heat Treating Forum on KnifeDogs' started by antleygd, Dec 4, 2012.

  1. antleygd

    antleygd Active Member

    For several years now I have made knife from old HC or WHC marked railroad spikes. I have sold these knives with the understanding they make okay knives not good knives due to the lack of carbon. After purchasing a Hardness Rockwell C Tester, my story is changing.

    The blades are forged, roughed out and set up. With a torch using the Bill Moran method of heat treating, I thermal cycle the leading edge of the blades three times allow to air cool until the "shadow" moves thru the blade. On the last cycle the blade is quickly quenched leading edge down tip point north (for what ever difference that makes) in a stiring fasion in 30 weight ND motor oil.

    Because of the lack of carbon in the knife I do not bother drawing these blades. If anyone breakes one of my RRS knives I can afford to give them another one. I want to keep all the hardness I can in these blades.

    The knife is finished and polished. I have tested several blades expecting to see hardness of 40C to 45C at best. I was supprised at the solid 57 HRC that I am consistantly getting.

    I hope this information is usefull to someone. I am open to comments as well. I dont know everything. In fact the more I learn the more I reailize how much I dont know. This process works for me.....

    Gary - Antley TX Knife and Forge, Groveton Texas
  2. Mike Carter

    Mike Carter Well-Known Member

    RC 57 is really surprising. According to the railroad specs I have "High Carbon" spikes may contain NO MORE THAN 0.30% carbon yet you are getting a hardness equivalent to steel with 3 times that much carbon.
  3. LRB

    LRB Well-Known Member

    I think you need to test your tester, your test blocks, or even your proceedures in testing. That just ain't right. Your original expectations sound much more correct.
  4. Doug Lester

    Doug Lester Well-Known Member

    I don't know about the HRc readings but I would stop using motor oil for them, actually I'd stop using motor oil, and quench them in water because I'd expect them to be very shallow hardening. I would also "temper" them at 300° one time for two hours as a stress relief. As for your other oil quenching steels, i'd look at something like canola or peanut oil or even a commercial oil. All of which are a little faster and safer than motor oil or transmission fluid.

  5. Martin Brandt

    Martin Brandt Active Member

    I have always HTed HC spikes in Super Quench to get the most possible hardness out of them , then tempered at 300F twice to stress relieve and make sure all is Martensite.
  6. KenH

    KenH Well-Known Member

    Martin, did you ever get a chance to get a Rc test on them with your method of HT'ing? I'd be interested in seeing what you get. I've only made one RR spike knife, quenched it in water. I didn't have a Rc tester then, but it sure didn't "seem" all that hard. I would have guessed in 40's the way a file cut? The guy who wanted it didn't plan to "use" it, just hang on wall.

  7. Wayne Coe

    Wayne Coe Forum Owner - Moderator

    I have been making knives from RR spikes for a couple of years. Matter of fact have won the Best Rail Road Spike Knife Contest at the Batson's Blade Symposium for the previous two years and tied this year. I quench in SuperQuench and draw a temper to 400 degrees as per Rob Gunter's suggestion. My spikes are marked MC on the head. Rob told me to expect to get a RC of around 54. My wife has a Case Equine Special and I have to sharpen her knife more often than mine.

    Well the one in the Batson's contest this year was a folder and had a Damascus blade so I guess that doesn't count as to the hardness of RR spikes.
  8. Martin Brandt

    Martin Brandt Active Member

    I've never Rc checked one as they are beveled, and I figured with .30 %-C they would NEVER be what you would call a hi-performance knife. That being said they are tough as hell, and who in their right mind would want to carry such a heavy club on a regular basis. They would have been a great knife in the fur trade era compared to stone blades, and mid 50's Rc is what most trade knives were as I understand. I do enjoy pushing them as far as can be though for fun. I make a grenade twist handled dagger with a 7 1/2" blade. Also made a plaque and spike knife with blade modeled after a WW II era RH PAL 35 USN utility knife and scales of hickory, with square nails for pins. This one went to a fathers son who was receiving his Navy pilots wings. The plaque was recessed and the cavity got two rare earth magnets and flocking to hold the knife, with room on the plaque for an engraved plate with details of said accomplishments. The spike he had found while camping as a boy, the hickory was from a great grandpa's old axe handle, and the square nails from the families pioneer era homestead in our area. This knife was one that got me onto pushing RR spikes to the limit. Since I had his spike from his father to use I had to see how much blade I could get, past the standard twist handle spike knife so many do. Couldn't screw up on their family spike so I practiced on mine first, and found that if I fullered the handle area to 1/4"thick x 7/8"wide then made the blade I could get a lot more blade, and my experiment with my spike ended up being an 8" French chef shaped blade, with forged finger guard, pewter bolsters, and ebony scales. a regular rifleman's long knife with a spike head on it. After that I knew I could make the 5 1/2" PAL USN blade on his spike easily. Wish I could figure out sending pics and remember how to do it, to send some here. Brains just not wired very well for computer expertise.
  9. KenH

    KenH Well-Known Member

    Well Martin, you might not be computer savvy, but it sure sounds like you are really the artist with RR spikes. That plaque setup sure sounds like an impressive display. Feel free to email photos to me and I'll be happy to post for you.

    Ken H>
  10. Chill8433

    Chill8433 Well-Known Member

    I was thinking the same thing Ken. I'm trying to picture the RR spike knives, but my brain is probably not doing them justice. I would enjoy pics if possible Wayne and Martin.
  11. me2

    me2 Well-Known Member

    Assuming everything else is spot on, and the hardness tests were done accurately (level surface, fine finish, etc), it sounds like your spikes have a carbon content in the 0.4% range, maybe a tad higher. Yes, they should be tough as nails. I always wanted one, but whoever said they were heavy was right.
  12. ARCustomKnives

    ARCustomKnives Well-Known Member

    This is along the lines of what I'm thinking.

    Is it possible you're testing over scale from heat treat? Have you tested a calibration block or another high carbon steel knife? Rail Road spikes by design can't have too much carbon as they will become brittle and fracture, which is a huge liability when several hundred tons of train are bearing down on the rails they hold in place.
  13. stezann

    stezann Well-Known Member

    I don't think the RR spikes fall into precise carbon %, so certain variability... the as-quenched hardness may be in the 55-58 hrc, especially when overheated.
    An accurate hrc reading requires perfect flat parallel clean surfaces, and a machine "zeroed" with sound reference.
  14. franklin

    franklin Well-Known Member

    Well i just had peter martin test one that i did that was quenched in water, 200 draw and i think that hit 38 or 40 rc he said. And think he said that was the same that he was getting from hc spikes.

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