Kangarhcuse

Basics in blade design

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I have just started blacksmithing. Most of my scrap metal is railroad spikes found at flea markets. Normally i trace the spike on paper then set up the curves and design to what I want to forge. I am beginning with simple blade shapes, but then want to move into longer and more distinctive blades. What I haven't researched yet is how flat should one of these blades be and how far can you draw out, some of these scrap pieces. As in my most recent plans i have 5 an ahalf to 6 inches of train spike(as steel left over after handle) can i form a 8 in blade easily? 

Ps iv only had about 2 ok days of forging , still adjusting my forge and work space.

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Welcome to the site.

Please do more research on bladesmithing on this site.  You will find that while spikes are great for some things, including testing out blade shape and learning forging technique, they aren't really good steel for making knives.  Not enough carbon to harden effectively with conventional treatments.  Not to mention the potentially questionable aspect of their sourcing, though if you are getting them from flea markets you are probably OK.

If you are really interested in bladesmithing I strongly recommend that you take a class in same from an accomplished smith, or at least get Jim Hrisoulas (http://www.sharpeningsupplies.com/The-Complete-Bladesmith-Forging-Your-Way-to-Perfection-P150.aspx?gclid=COrI747d_skCFQovaQodEywBNw ) and Steve Sells books and study them.  There is a lot on the internet that will send you in the wrong direction.  The forging side of making knives is only the tip of the iceberg.  Filing, grinding, heat treatment, steel selection, handles and sheaths are also in your future.

But to answer your question, if you have 6" of steel left after making the handle section of the knife you should easily be able to forge it out to an 8" blade (depending on the crossection of the material before and after).  Forging is all about moving a volume of steel from one configuration to another.  Basic geometry calculations can tell you what is possible, though you will lose some material to scaling.

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The neat thing about using actual blade worthy steel is that if you have a really good day at the forge you end up with a knife instead of a KSO.  As you can probably locate auto springs most places in the world and it makes a decent blade I would advocate working on it. Among other things higher carbon steels work differently than lower carbon steels. (and a typical automotive spring has double the carbon content of a spike even one stamped HC.

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Ok ill will look into the link. My uncle works for a large diesel shop, he may have some sort of springs. That i can cut and strighten.  What is a decent project that can be done with these rail road spikes. As art or useable things. Simple is kinda what im working at untill summer.

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Welcome aboard, glad to have you. If you'll put your general location in the header you might be surprised how many of the Iforge gang live within visiting distance.

There are subsections here on Iforge about rr spike projects that are jam packed with good ideas for you. I agree on the blade projects though, find steel with enough carbon to harden or blades won't hold an edge. Coil spring is easier than leaf spring to forge blades from in spite of the shape difference.

Frosty The Lucky.

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A nice simple project using rr spikes are Fredericks Cross's, a cool trick is leave the bottom on as a stand.

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I have a friend who forges them into garden trowels; lots of hammer time!   He uses a power hammer.   If you search of RR spike projects you will probably find *hundreds* all over the net...

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We have some very old tracks near us. I've found some ancient corroded spikes that look really cool. I made one into a bottle opener that made a nice Christmas grab bag gift. Another is a half-sized corroded spike I'm making into a letter opener for a gift. I'm going to polish the blade part to a mirror finish to contrast the corroded head-end which I just used a wire wheel brush on.

 

 

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On December 28, 2015 at 6:08 AM, latticino said:

 

You will find that while spikes are great for some things, including testing out blade shape and learning forging technique, they aren't really good steel for making knives.  Not enough carbon to harden effectively with conventional treatments.  Not to mention the potentially questionable aspect of their sourcing, though if you are getting them from flea markets you are probably OK.

Just one point on the hardness matter---there are *some* spikes made from higher carbon material.  These will have "HC" stamped on the head.  Those without the HC will make lousy knives.  Those with the HC will be about like a medium carbon knife with a minimum of .2% carbon (vs .06 min for standard spikes)--somewhat useful but not great.

hc.jpg

Here is a link to specific spike information from 1968 standards http://www.worldclassknives.com/spikes/spikes.pdf

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HC spikes top out at the boundary between mild and medium carbon steels .3 %  still not a good knife material.  the "3" rail clips have .5-.6 % C and so about double, 5160 automotive springs have .6 I would NEVER claim that .3% is a knife worthy steel, (I assume that the .2% is a typo as 1020 with .2% C is pretty much the definition of "mild steel") Shoot most rail would make a much better blade than the spikes that hold it down as rail has a higher carbon content for wear resistance!

The alloys for these things have published specs that are pretty easy to find.

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Maybe I should have clarified better--the intent was to emphasize how bad the average spike was for knife making and that if someone insisted on making a knife from spikes, at least use the HC version and have a slight chance it won't be utterly useless.  I had edited out the common phrase "knife shaped object" to describe results and now I wish I had left it in :) 

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