What steel is Thompsons hardened shaft?

Doc Hollywood · Feb 7, 2003

I have read almost every post here and have found many knowledgable answers to many of my questions (as well as some humorous ones). With that being said I will ask my question.

I have plans of some cable damascus blades in the works, but am not sure of the steel used to make up the cable. In order to make for a sharp edge holding blade I am planning on forge welding in some Thompsons hardened shaft I have access to in the form of injection molding pins. I believe this material is L6, but am not sure. I do know it is so hard that the cutoff wheel has a bear of a time with anything of any diameter at all. Will this make a good edge, and what material is it?

Thanks Folks,

Doc Hollywood

R. Lemmen · Feb 7, 2003

What type of "injection moulding pins" are you talking about? Ejector pins (the ones with a head on one end) are typically H-13 tool steel, nitrided for a surface hardness of 65-75Rc depending on the manufacturer. Manufacturers are less forthcoming concerning the material their guide pins are made of.

I don't know about "Thompson" shaft but other precision ground shafts are made from 303, 304, 316 and 420 stainless.

HTH

Doc Hollywood · Feb 7, 2003

Yes, these are the type that have the round head on one end. I thought I remembered these being made by Thompsons but may be very wrong.

I have a good supply of these and would like to be able to get a good edge holding blade without having it chip like mad in use. Any ideas?

R. Lemmen · Feb 7, 2003

The case hardening is only .001"-.003" deep. You should be OK once you've ground through it. The pins tend to chip due to the differential in hardening (65-75Rc case vs. 30-40Rc core).

I don't know if there is any way to remove the effects of nitriding through heat treatment.

Doc Hollywood · Feb 7, 2003

Can the pins be forged to say a square shape that would be easier to forge weld onto the cable billet or will the case hardening make cause problems with the forging?

Wild Rose · Feb 7, 2003

According to a thread on Thompsons Shafts on CKD it's 1566

Here are the specs.
1566
Carbon 0.60-0.71
Manganese 0.85-1.15
Phosphorous 0.040 (max)
Sulfur 0.050 (max)

Here's a link to the thread on the CKD:
http://www.ckdforums.com/showthread.php?s=&threadid=12036

Hope this helps.

Chuck

R. Lemmen · Feb 17, 2003

Originally posted by Doc Hollywood
Can the pins be forged to say a square shape that would be easier to forge weld onto the cable billet or will the case hardening make cause problems with the forging?

Hi Doc,

Just wondering if you had any luck with these pins?

When I answered you the first time I was thinking mainly of the case hardening and how to remove it. As I thought about it, some new questions came to my mind.

H-13 is a high chromium HEAT SHOCK RESISTANT tool steel. Did you manage to forge anything out of it? I think that it's hot hardness would make it a severe PITA to forge! I would also think that it would be difficult to weld to other materials in damascus.

So, any luck?

Chuck Gedraitis Knives · Feb 17, 2003

Cable can be forged without adding anything to it. Just make sure the welds are clean and the heat treatment is done correctly and you should have no problems. The beauty of making cable damascus is the simplicity of it!