Dive knife

[Little Kieran]

Was just wondering whether any of you fine smiths on here have ever been commissioned to make a dive knife, I'm a keen diver and rather fancy a special knife I've made myself, but am unsure what materials and processes I should be looking at, considering the exposure to salt waters and such..

Any help greatly appreciated    

[srtben]

If it was me, I would lean towards a nitrogen stainless steel. Anything else can still rust in salt water.

 http://www.alphaknifesupply.com/zdata-bladesteelS-N680.htm

[Little Kieran]

Wow.. I was looking at the 420 and 440 series but for the ease of manufacture and the corrosion resistance that looks like a perfect choice..

[srtben]

Unless you are setup with a kiln and Liquid Nitrogen, I would send it out to get heat treated.

[Little Kieran]

As fun as liquid nitrogen sounds, I feel like even for me, messing with that might be foolish..

By the way Ben, liking the look of the pig sticker, how does the elmax machine?

[srtben]

Its pretty tough, about .002" at a time.

[Little Kieran]

I suppose at least the adage of measure twice, cut once holds true at a pass of that depth haha..

Nonetheless, you have more patience than me!

[srtben]

Setup and measuring took longer than milling. .002 at about 15-20 secs a pass, only milled to .050 depth. It only took about an hour or so to do the math, measurements and milling.

[Bobby Urban]

That is pretty interesting right there Ben?  Never heard of such a thing.  I do know that Titanium is used in dive knives for corrosion resistance and works pretty well.  Depending on your desired performance and use a dive knife really needs very little in the way of HT as it is best left somewhat soft and used more for prying and such with a serrated portion available to cut rope, fishing line, etc. Blunted tips and avoiding really sharp pointy things is good in deep cold water with heavy gear on.

[Doug Campbell]

I've not worked the stuff but I have a Matt Diskin assisted opening folder I bought several years ago made from Aus8 steel. It has been in the ocean hundreds of times with no rust. I rinse and oil it after it's been in salt water and it holds a pretty decent edge also. Not sure about the HT and temper though...