Since this got another thread off of the rails. This isn't a treatise on making for a complicated sharpening method (the best may actually be the cheapest - short and long term).
It's the oft-said advice that everything will make a tool last equally long and be equally sharp. That's not true, and it's been tested twice, at least - and I'm sure it's actually been tested more like a dozen times.
The standard for getting an edge is getting the shape of it, then polishing the very edge. The sensible way of doing this (and the laziest) is to use a medium abrasive off of a ground edge, remove any remaining wear if the edge isn't reground, and then polish just about the smallest amount that you have to. If you use something like diamond on wood (which will cost you only a few dollars), it replaces a leather strop.
For the purpose of actually seeing the results from doing this (which were obtained in a test used for another purpose), the number of feet planed (in beech) using an O1 iron and various media (same plane, finished edges viewed through a microscope to confirm wear and defects removed, etc), the results were as follows (feet planed before a plane failed to stay in a cut):
1 micron diamond finish: 840 feet
dan's black ark (the finest I know of, new or old): 700 feet
5 micron diamonds (about 2 to 3 times as fine as a settled in 1200 grit ezelap): 568 feet
After a rerun to confirm results in a second piece of wood (5 micron test omitted, it was far less pleasant to plane with to say in the least):
1 micron diamond finish: 908 feet
dan's black ark: 738 feet
Strangely similar relative comparison, and the test was ceased. 2.5 micron diamond results, I cannot find, but they were only slightly better than 5 micron.
Loose diamonds were tested on a precision cast plate (not a plane sole or anything with significant defects).
The point here is important. If you are woodworking, you have to be able to sharpen. Once you're able to sharpen, you are wise to do better at it and sharpen to a finer level (without introducing extra time) because your results will improve and your effort in getting them will lessen. You will also be well set up to move on and sharpen things other than straight plane irons and chisels.
It's the oft-said advice that everything will make a tool last equally long and be equally sharp. That's not true, and it's been tested twice, at least - and I'm sure it's actually been tested more like a dozen times.
The standard for getting an edge is getting the shape of it, then polishing the very edge. The sensible way of doing this (and the laziest) is to use a medium abrasive off of a ground edge, remove any remaining wear if the edge isn't reground, and then polish just about the smallest amount that you have to. If you use something like diamond on wood (which will cost you only a few dollars), it replaces a leather strop.
For the purpose of actually seeing the results from doing this (which were obtained in a test used for another purpose), the number of feet planed (in beech) using an O1 iron and various media (same plane, finished edges viewed through a microscope to confirm wear and defects removed, etc), the results were as follows (feet planed before a plane failed to stay in a cut):
1 micron diamond finish: 840 feet
dan's black ark (the finest I know of, new or old): 700 feet
5 micron diamonds (about 2 to 3 times as fine as a settled in 1200 grit ezelap): 568 feet
After a rerun to confirm results in a second piece of wood (5 micron test omitted, it was far less pleasant to plane with to say in the least):
1 micron diamond finish: 908 feet
dan's black ark: 738 feet
Strangely similar relative comparison, and the test was ceased. 2.5 micron diamond results, I cannot find, but they were only slightly better than 5 micron.
Loose diamonds were tested on a precision cast plate (not a plane sole or anything with significant defects).
The point here is important. If you are woodworking, you have to be able to sharpen. Once you're able to sharpen, you are wise to do better at it and sharpen to a finer level (without introducing extra time) because your results will improve and your effort in getting them will lessen. You will also be well set up to move on and sharpen things other than straight plane irons and chisels.