Knife Steel: M4

I have become quite a fan of M4 knife steel. It is important to note that M4 is not a stainless steel and it will rust if not cared for. This has yet to be a problem for me (but I live in the Arizona desert). In particular, keep some oil on the pivot area.

A fellow got his hand on Spyderco Military's in both M4 and Cruwear, took pains to sharpen them identically, and proceded to chop up manila rope to see how they would do for edge retention:

I started by taking both knives over my UF Sharpmaker stones 20 passes per side. I then stropped each side 10 times on my strop using green compound. I even reloaded the compound between knives so that they started AS equal as I could think. Both edges would easily push cut magazine paper. I like magazines because they are very thin paper and give a nice clean cut.

I started with my Cruwear Millie. I used 3/8 Manila. I know others use 5/8, but Home Depot only had 3/8. Besides, since both knives used the same rope, same day, the thickness isn't important. I used a soft white pine 2x4 as backing to minimize edge degradation. Very soft wood. The test was like this: 12 cuts through rope, then a few slices on mag paper to test sharpness, then 12 cuts etc. I immediately noticed what people talk about on edges being optimized for different types of cutting media. I had a screaming sharp edge that was difficult to cut the rope with. It wanted to slide over the rope with almost no bite. I figured I was in for a long morning. The Cruwear did its thing ok once I got my technique down. I started at the back ricasso area and made one long draw stroke to the tip. I ensured I was using the entire blade this way. The Cruwear made it to 252 cuts before it had any real "hitches" in it's paper cutting. I then, in an effort to move things along, took a cardboard box and made 12 long slicing cuts with the Cruwear. It did this fine, but at the end would noticeably catch on the paper, and it would not shave leg hair. Not bad I figure.

I then set up the M4 and started in on the rope. I immediately knew M4 was in a different league. It would practically push cut the rope, and I had to ensure I used the entire edge to keep the test valid. The M4 cut like a Banshee!! I had to go from testing every 12 cuts to testing every 20 because it was pointless to keep stopping. In order to keep the test valid I stopped at 252 cuts and performed my cardboard cutting again. Same box, same 12 cuts. I then cut the magazine paper. The M4 would still cleanly push cut the paper with just the weight of the knife, no pressure on my part. The M4 would not shave leg hair at this point, but it was still push cutting paper so I continued with the test. Another 50 cuts for a total of 302, and it was still going strong. I figured that a 50 cut margin of victory was very, very decisive, and stopped.

For me now, it's Sharpmaker brown stones then a swipe or two to knock the burr off. It is a night and day difference what a little "tooth" will do for cutting performance.

Feedback? Questions? Drop me a line!

Tom's Knife Info / tom@mmto.org