Steel

[DC]

After reading this forum for a while I realise that there is a bunch of different kinds of steel out there with all different heat treating methods. Do any of them hold a significantly better edge than good old high carbon steel?

[Mesophilic]

Quite a can of worms you opened there DC.  The answer is very complicated.  Many modern steel alloys will hold an edge longer than plain old carbon steel.   There are often tradeoffs.  For example D2 which is semi-stainless will outlast 10xx series steel, IMO, but requires much much more work to resharpen.  I find the same thing with S35VN, 3V, and many more.  Sometime the tradeoff can be a chip prone edge.  Much depends on the heat treatment and blade geometry. 

Within the high carbon category there's also modernizing of alloys.  52100, IMO, will take a keener edge and hold it longer than 1084 or 1095.  5160 wont stay as sharp as 52100 but is tougher, so It may not shave after felling small trees but will continue to fell trees where the edge may roll or flatten quicker on plain carbon. 

These are my takeaways after making hundreds of knives in various steels, and like I said,  it gets complicated.

[DC]

Thanks

[Mesophilic]

No problem.   

Personally,  I've been getting real sick of working with super steels and have taken a break and gone back to plainer carbon steel for a bit.  Post heat treat they are extremely difficult to finish, hard on belts and tools, some are so abbrasion resistant that they just laugh at even 60 grit sandpaper.   Did a kitchen set for a guy out of s35vn at a high hardness and 60 grit sandpaper was merely polishing the steel.  I don't put an edge on using the grinder so they take four to six times longer to cut a fresh edge on them.  Wears out my sharpening stones real quick, too.   

The up side is that I've never had to touch up an edge in the field, and with regular stropping using Bark River green compound or diamond paste they'll usually come back to shaving sharp fairly easily (won't fix a chipped or damaged edge, knife jas to still be usably sharp for this to work).

[Mr. Woolery]

I never really got into the exotic steels, as close as it came was ATS-34 and 440C.  That said, I don't think I am far off when I say that one other tradeoff is how keen an edge you can get.  With properly heat treated carbon steels and properly heat treated stainless steels, it just isn't possible to get the stainless as sharp as the carbon. 

For most uses, say hunting, this doesn't really matter.  But you won't make a straight razor out of 440C and expect it to be as fine an edge as with 1084 or 1095.  Because shaving hair from your arm and shaving stubble from your face are two very different degrees of sharp. 

I have recently gotten into spoon carving and the tools I use leave the final surface on the spoons.  This means that the sharper the knife, the nicer the spoon.  I finish them pretty fine.  And resharpening isn't really a thing with carving knives.  When they start to lose their bite, I strop and keep them sharp.  They should never get dull at all. 

As said, I am ignorant about the really exotic steels, so only take this as one man's experience with a relatively narrow range of steels.  But there are good reasons why leaf springs, saw blades, carving knives, and files are made from fairly simple carbon steels.  You use the best steel for the intended purpose.  If your primary purpose is corrosion resistance, use stainless (I'd hate to use a carbon steel fillet knife for salt water fishing), but if your purpose puts more value on resilience, sharpness, or toughness, you will have to find a way to maintain the surface and deal with rust. 

-Patrick