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Ruining the heat treatment


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I am in the middle of making my first knife out of a rail road spike and am about to heat treat the blade. after that is done I am going to hand sand the knife until I reach 1200 grit when I have nothing finer. But to me that is not shiny enough. I would like to buff it but I am afraid that if I get it the blade too hot, I might ruin the the heat treatment. Is this possible?

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Heat treatment does not mean harden. Heat treatment can make something harder, softer, no change or even just not as brittle.

Now SOME rr spikes will have enough carbon to be able to harden them some using superquench, they will never get as hard as a good knife steel will. Many rr spikes do not have enough carbon to harden appreciably.

Which type did you use?

So if you are afraid of messing up the heat treat of a knife, keep the blade cool as you buff it---dip it in water regularly or only buff for short periods at the time.

Wasting 1200 grit paper on a RR spike knife is not a good return on your investment IMNSHO! I would buff with a sisal wheel and black compound after 400 grit.

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Most railroad spikes are in the neighborhood of 1020-1050. The ones with the "HC" are on the high end when it comes to carbon. Correct me if I'm wrong but I think they use they have to use the HC ones at junctions or high stress corners on the trackline.

Anyway.... They can be hardened but not to the point of usefulness as knife steel. They are better left for hawk heads and art pieces.

To answer the original question.... you can buff a hardened knife..... just keep the heat down.



Rick

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American Railway Engineering Association's Specifications for Soft-Steel Track
Spikes. Original document, 1926, revised last in 1968

Two classes of track spikes are given specifications, both low carbon and high
carbon. Two sizes of track spike are identified, one of 5/8 inch square shaft a
nd one of 9/16 inch.

Page 5-2-1. "A low carbon track spike will not contain greater than 0.12% carbo
n nor greater than 0.20% copper.

Page 5-2-2. Section 6a.
Bending properties: The body of a full size finished spike shall stand being be
nt cold through 180 degrees flat on itself without cracking on the outside port
ion of the bent portion.

Page 5-2-2 Section 11. Marking. A letter or brand indicating the manufacturer s
hall be pressed on the head of each spike while it is being formed. When copper
is specified, the letters "CU" shall be added.

Page 5-2-3: Specifications for high carbon steel track spikes 1968. Carbon not
greater than 0.30%, nor greater than 0.20% copper. Page 5-2-4. Section 6a. Bend
ing properties: The body of a full size finished spike shall stand being bent c
old through 120 degrees around a pin, the diameter of which is not greater than
the thickness of the spike without cracking on the outside portion of the bent
portion.

Page 5-2-5 Section 11. Marking: A letter or brand indicating manufacturer and a
lso the letters "HC" indicating high carbon, shall be pressed on the head of ea
ch spike while it is being formed. When copper is specified, the letters "CU" s
hall be added."

Additionally included in a fax to Mike Blue by the gentleman at Wellington indu
stries, a division of Sheffield Steel:
"Because of the bending tests required, the carbon content will not be greater
than 0.30%. After all, brittle spikes would not be desirable as a track spike.
A bent spike still holds the rail while a fractured spike would not. The conseq
uences for the industry would be too great to consider. However, we refer to th
em as high carbon, they are not within the range of steels known as high carbon
or hypereutectoid according to the steel industry standards, and have not been
since at least 1926, when most track spikes were previously manufactured from
wrought iron."

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Chuckster when I read your reply above about the heat treat I kind of thought you were a bit testy in response. I thought aboiut it a while and realized once again that with a multi-national site we have done really well with the language problems that brings. Some areas of states countires even continents have different terms for the same thing.
Thomas reminded me that heat treatment does mean alot of things. And that makes your thought that RR spikes can indeed be heat treated a valid one. Looking at the geneeral tone of the answers I think wot folks are saying is that you can spend a ton of time on a spike knife and when you are done you will have a well done spike knife. My thought is that if you spend the same time with better steel you may even spend less time and have a really nice knife when finished. And the beauty of all of this is it is your choice. Make wot you wish from wotever you like.

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I suggest people "practice" with a good steel in case they get lucky and everything works out---then they have a good/great knife. Practicing on a poor steel means that 1 they are not learning exactly how to work a better steel and 2 if they get lucky they still have a blade made from a poorer steel.

May I point out that the clips used by RR can be almost double the carbon content of a spike---depending on maker and use.

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Chuckster when I read your reply above about the heat treat I kind of thought you were a bit testy in response. I thought aboiut it a while and realized once again that with a multi-national site we have done really well with the language problems that brings. Some areas of states countires even continents have different terms for the same thing.
Thomas reminded me that heat treatment does mean alot of things. And that makes your thought that RR spikes can indeed be heat treated a valid one. Looking at the geneeral tone of the answers I think wot folks are saying is that you can spend a ton of time on a spike knife and when you are done you will have a well done spike knife. My thought is that if you spend the same time with better steel you may even spend less time and have a really nice knife when finished. And the beauty of all of this is it is your choice. Make wot you wish from wotever you like.


I am sorry sounded testy Rich. I just have spent a lot of time on the knife and hoped that I could heat treat the knife and make it hold an edge for awhile, though probably not as long as a good quality steel knife such as that created from a leaf spring . I have spent months doing preliminary research that suggested that it could be done but since I am such an inexperienced bladesmith I became anxious when Pete said that it could only be a letter opener since that was not it's intended purpose. I also have 19 other spikes that I intended to make into knives not letter openers. I want to be able to say that I made a knife. I want to be a bladesmith.
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  • 2 weeks later...

I make spike knives from HC spikes, there is no need to temper, just quench in Super quench 3 times with blade pointing magnetic North. My Knives will bend 90 3 times before breaking. Sand with 300 grit, buff without gloves, dip in water when to hot, sharpen at 25 degrees, will cut through 2x4, and still hold edge. 19 degrees was to thin, blade deformed when I hit a knot, hope this helps.:cool:

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shut up chad osborne you will not give the lad a false sence of security......jimmy


I can't tell by your wording whether or not you are joking. Are you saying that what Chad said is untrue? I have never heat treated a spike before so Chad's statement and your statement have me very confused. Please clarify.
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I make spike knives from HC spikes, there is no need to temper, just quench in Super quench 3 times with blade pointing magnetic North. My Knives will bend 90 3 times before breaking. Sand with 300 grit, buff without gloves, dip in water when to hot, sharpen at 25 degrees, will cut through 2x4, and still hold edge. 19 degrees was to thin, blade deformed when I hit a knot, hope this helps.:cool:


Some more details would be greatly appreciated. What blade thickness do you have? What blade/grind geometry? Are you chopping or batoning through that wood? Across the grain or with it? What wood is that 2x4? Just how 'sharp' is the blade before and after going through the 2x4? Did you try any other grind angles than 25 and 19 degrees? How close to magnetic north do you consider 'acceptable'? ;)
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you don't need to quench 3 times, recommending not using gloves while sanding of buffing i a accident waiting to happen,i do agree with super quench but just about any semi sharp piece of steel will hack through a 2 x 4,i guess i just read more into it than is there,be well,jimmy


Thank you for the clarification. I was worried that super quench would not work or something. I did not know you meant not to quench 3 times. I will quench once and not temper as I have been advised and I will wear gloves as I have taken shop class and have seen pictures of "accidents."(I call them human error) I Think I will finish it this month. I just have to get the supplies for the super quench.
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Chad: you were joking about the "magnetic north" thing right?

Gloves are a matter of choice. You are often not safer with gloves and in some cases less safe. You usually have a better grip and dexterity without gloves and gloves offer very little real protection. While gloves often make you feel safer, they often get hung up and snagged when bare hands won't. Just because you get hurt not using gloves is no proof that you would not have gotten hurt with gloves.

When I worked in a sheet metal shop we often had to take down sheets that were stored of shelves 3 - 4 feet off the ground. these were four foot by ten sheets 16 - 20 guage oiled material. One guy on each end, slide it out and the middle would flop to the groumd as you cleared the shelf. Gloves WERE NOT ALLOWED! Use bare hands, hold on tight and move with it. We could hold on with bare hands, but it would slip and slice right through gloves.

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I don't no about you guys but when I am making knives they talk to me, grind here, file there, bend here, the knife tells me when it is finished. I thought you couldn't go wrong with a triple quench. Buffing without gloves is so you don't over heat the blade, I allways were gloves for everything else. magnetic North by a compass is what I have been told, my first knife just happened by chance to be quenched faceing north so I have not changed. Enjoy what you are doing and have fun.

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Some more details would be greatly appreciated. What blade thickness do you have? What blade/grind geometry? Are you chopping or batoning through that wood? Across the grain or with it? What wood is that 2x4? Just how 'sharp' is the blade before and after going through the 2x4? Did you try any other grind angles than 25 and 19 degrees? How close to magnetic north do you consider 'acceptable'? ;)


Ok blade thickness differs knife to knife, my last 2 were 5 mm at base of spine, and tapered down to 2 mm at the tip. The blade is a flat grind, and sharpened at 25 degrees on a diamond gatco kit, and then stropped with green buffing compound on a leather stropp. Chopping through wood across the grain, (standard pine 2x4). Hair shaving sharp before, and not hair shaving sharp after; but a couple of swipes on the stropp fixed that.
Have not tried other grind angels, but I liked the 19, I think it will work great for Deer season. A standard compass should do fine. I just happened to quench my first knife by accident with the tip faceing North, and a lot of ol timers swear by it.

Here is my process for Railroad spike knives (they make good knives not great knives) 1) Forge blade, normalize. 2) Grind and shape blade, stamp name and serial number in handle. 3) Heat to working temp,then twist handle, heat and normalize again. 4) File sharpen and smooth all areas that need it heat and normalize. 5) Sand, then buff to mirror shiny(at this point it would make a nice letter opener) 6) triple quench, sand and buff to mirror shiny, usually 40 up to 300 grit, black, then green buffing compund.7) Sharpen on diamond gatco at 25 degrees, then stropp with green compound....... finished.
the handle is easy because the knife is all one piece.
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