Cable Knife

[triw]

I read that Teachingclay was given some elevator cable.

"I got ahold of a bunch ,75 feet or so, of elevator cable tonight. Most of it is cut into short lengths to be trimmed to the desired piece later. Turns out its not solid, according to my friend the elevator repairman, none of it is. It has a jute rope core, which would leave a 1/4 hollow in the center."

My understand is: that mild steel is the core of a Japanese samauri sword. When it is quenced the mild steel srinks differently from the high carbon steel and causes it to curve.

My question is if you took the rope out and replaced it with a 1/4" mild steel rod then forged this into a knife blade how do you think it would react when quenched? Would there be enough mild steel to make a difference?
Any ideas?

Thanks for letting me pick your brains. William

[Justin Caradoc]

sounds like someting to play with :)

[Rich Hale]

I wonder how you would remove the rope core and replace it with steel? may be able to burn it out I suppose. For me it seems there is not al ot fo use for mild steel in a knife. If youi have a 3/4" cable and take out the core that leaves about the volume ( in rough shop terms), of a bit more than half inch of cable volume. Now add back the mild steel and you again have about 3/4" of cable, about one third of which is mild steel. I have heard quated different specs for cable as to carbon content, And I thing the most I have heard was .80 or a bit more. Deduct the mild steel from that and you are left with less that .60 carbon content in the billet. Personnally I prefer more carbon in my knives. Yes you can add another steel to the mix and gain back some carbon. And as mentioned it may be fun to play with. make up a billet and heat treat it and test to see how it works. For me I would rather go to one of my few recipes for useing steel that I know works and weld up a billet, pattern it, make a knife and again test it to see how it works. ( I know there will be someone that will work out the math in precise terms, But I tend to first get a ball park figure before I work it out on paper. And keep in mind that I weld billets in the sunshine in a warm place. May be why I go with proven plans and not a lot of research and development. Enjoy and let us know if you try this and how it works.

[ThomasPowers]

Japanese swords curve during quench even when made with a single homogenous steel; if it's shallow hardening and the clay hardening method is used.

[tantrum86]

my experience with all the cable ive used is that it is either 1095 AKA extra improved plow steel or 1075 which is commonly called improved plow steel the reason i know these specs is because the cable i have comes from a crane and those are the steels they spooled off and on during a 5 year maintenence.I myself would however stay away from any cable that is not soild core as it is really difficult to remove fiber cores and if you burn em out it makes a heck of a mess. If you need some good solid core cable i have quiet a bit and wouldnt mind sharing hope this helps.

[king fish]

I would give it a try. if you have time to spare weld it up, fold it a few times see what ya end up with. should make good looking knife.

[Chuck Richards]

If you cut the cable to 6-12" pieces you can take it apart and remove the core. I too would avoid using this material though but I have a bunch of cable to play with. Try to fill the void with something, a piece of HC steel would be best. I would also tack weld up the ends with a stick or MIG welder. This prevents unraveling when you heat it for welding. Also make sure you burn out all the oil. Wayne Goddard describes his method in his books.

Good Luck

[JPH]

Hello:

What is the diameter of the core" If it is 1/4" or so..go head and use cold rolled 1018 as a replacment. You will never get the CR anywhere near the edge of the finished piece unless you do something really off the wall working it. Just wrapp it in tight and twist it shut at Cherry Red prior to welding it solid.

You will, more likely than not wind up having the CR running down the long axis of the blade, more or less dead centre of the forging. This could be compared to the Japanese method of Kobuse construction with the HC wrapped in a U around the WI core, or to some of the N European methods of lamination welding HC to a WI core for a sword.

I would be very comfortable in doing this, no problem at all..but then again..what do I know?? I am just some olde hammer head working outta his garage...

JPH

Edited September 8, 2008 by JPH

[Chuck Richards]

I have finally graduated to working outta my garage. Used to forge in the back yard. I just had a well put in and the drilling rig had to have it's cable changed. Yup I aquired it. About 100' of 3/4". I just wish I could turn the cable into enough $$ to pay for the well, cha ching. Nice cable though, did a test forging and it HT'd really nice. Anti twist so the pattern should be interesting.

[hammerhandsyd]

cut the cable open on one side then take out the cord then add a low carbon, weld to gether with an edge of low carbon stick out oposet the edge so it will curl

[matt993fod]

I'm not entirely sure about the whole quench-induced-curvature thing.

I've never heard of it in any of the bladesmithing material I have read. "The craft of the Japanese sword" makes no mention of such an occurrence.

If the differing expansion rates of mild and HC steel were really pronounced enough to create curvature on a scale like that seen in Japanese swords, surely whenever a pattern welded blade was quenched, it would twist up like a deranged bunch of bananas.

These are my thoughts. What do you think?

[Chuck Richards]

Actually on page 94 of The Craft of the Japanese sword does talk about the curvature and how to adjust it. It does not require mild steel to get the Sori (curve). Just the application of clay to the back and a quench in water. If you quench in oil the curve can occur in the opposite direction. I watched Dan Pfannenstiel do a wakasashi quench. It was straight when it went into the water and had a 1 inch sori when it came out. Really cool. I even saw a water quench somewere that filmed in the water. The sword curved toward the edged first then curved back and beyond to form the sori. Both of these were on mono steel blades.

[Jmercier]

One thing to keep in mind if you do a solid mild steel / 1018 core, is that carbon lowers the welding piont of steel, so you will need to get the billet hotter to weld to the 1018 without delamination than you would if it was a plain solid core cable, other than that, it should work just fine. I've been looking for a good source for steel cable myself, but havent been able to find any as of yet up in Rhode Island

[NateDJ]

Why can't you just take the core out and weld the cable itself. If you need a thicker billet, fold it and weld it again. I am not a pattern welder yet so I am asking because I would like to know.

I have some nicely rusted cable I could use at some point but I need to know how to clean the rust before attempting the weld, any ideas? Or do I not need to worry about the rust?

[matt993fod]

Thanks for the clarification, Chuck.