Recycling a knife

[Howie]

After reading about Nomad's job on that electricians knife – which is awesome, btw – I'm wondering how to tell what kind of steel you're working with in a blade.

I often come across old knives online or in shops, and think they'd make a great carver. But I keep reading that carbon steel is best – so how do I know what the blade is made from if it isn't stamped?

Thanks!

-Howie

[Nomad]

Sometimes if the knife is stainless, it will be stamped on the tang or etched on the blade. If the blade has patina on it, most likely, it is carbon. Knowing some history of the knives themselves also helps. An old copy of Levine's Guide to Knives and Their Values is a valuable resource.

Also, many stainless steels are not as bad as they often are made out to be so I would not get overly concerned. I have literally hundreds of stainless steel knives and they all work just fine. Never had a problem getting a shaving sharp edge on any of them. Buck is an example of a company that uses a pretty cheap grade of stainless on most of their knives (420HC), but it hardens up well and will hold an edge well. Just don't pry with it.

As a general rule, Old Timers will have 1095 carbon steel unless marked as Schrade+, it which case they will be stainless. The older Queen steel knives were stainless. Queen now uses a lot of D2, which is semi-stainless. Older Case knives are all carbon. I think Case started using stainless back in the late 60s but I'm not sure on that. They usually mark them though and if you do a search, you can find a guide that will tell you what the tang stamp numbers mean.

Most of the stuff coming out of China is 440 steel on the low end. (440A). This is similar to AUS 6, a Japanese stainless. 440B - Aus 8 and 440C = Aus 10.

A simple way to test a steel to see if it is stainless is to dip a toothpick in gun bluing and touch it to the blade. Carbon blades will usually stain very dark pretty quickly.

Do a search on the net for a knife steel guide and you will find a lot of information.

[Buffalo Bif]

[QUOTE=

A simple way to test a steel to see if it is stainless is to dip a toothpick in gun bluing and touch it to the blade. Carbon blades will usually stain very dark pretty quickly.

QUOTE]

Does gun bluing help protect against corrosion?

[Howie]

Thanks Nomad! I'll check out that book!

Also, I'm in Southern Ontario, Canada. We treat guns a bit different here

[Eddy-Smiles]

Sometimes...but not always, you can check to see if a knife is stainless by using a magnet on it. If the magnet doesn't stick then for sure you've got a good grade stainless. However, you could still have a lesser grade of stainless and have the magnet stick. Most likely the Chinese 400 grade will be magnetized.

[Claude]

The traditional way is spark testing.

Just Google "steel spark test" for lots of links. Here's one:
Spark testing - Wikipedia, the free encyclopedia
Claude

[Nomad]

[QUOTE=Buffalo Bif;436556]

Originally Posted by

A simple way to test a steel to see if it is stainless is to dip a toothpick in gun bluing and touch it to the blade. Carbon blades will usually stain very dark pretty quickly.

QUOTE

Does gun bluing help protect against corrosion?

Gun bluing will turn the blade quite dark. It won't prevent rust but it does protect the blade just like a natural patina does. It won't be as protective as a high dollar bluing job though. At least that's my understanding of it. I like the natural patina look much more than I like the gun bluing patina. It's almost a moot point for a carver because stropping will remove patina.

[Nomad]

Originally Posted by Eddy-Smiles

Sometimes...but not always, you can check to see if a knife is stainless by using a magnet on it. If the magnet doesn't stick then for sure you've got a good grade stainless. However, you could still have a lesser grade of stainless and have the magnet stick. Most likely the Chinese 400 grade will be magnetized.

Eddy, I'm sure that works for certain stainless steels in certain applications but stainless knife steel is usually high enough in carbon to be magnetic. To test this, touch a magnet to the blade of a Swiss Army knife, which is definitely stainless.

I believe Stellite and possibly Talonite are nonmagnetic.