How important is a progression of stones?

I think it is very important to have a progression of stones in your sharpening routine whether you are using synthetic or natural stones. It does not need to be a numerical system but it should be based on grit action. Of course synthetics from company to company can vary in the actual grit particle range, a stated Norton 8K may me finer then a 8K Naniwa, Shapton or King and naturals can be difficult to figure out. But over time if you are able to create a ladder of stones (grit) to help you build an edge step by step, stone by stone as a foundation leading up to your final polish I believe your edges will last longer.

A longer lasting edge is important. A sharp edge feels good and that is what we are all looking for, but as the days or weeks or years pass the quest for a longer lasting edge surfaces as a rewarding goal too.

My reasoning for a progression of grits in providing a longer lasting edge in a nut shell is this. A sharpened edge is a damaged piece of raw steel at the very place where it meets empty air. Under a microscope it looks ragged and rough. This damage continues back into the interior of the steel away from the edge for a certain distance measured in microns, a very short distance, and less with finer grits. Off of a 60 grit grinding wheel this distance is greater, a 1000 grit a bit less and so on. Althought the distance is small the metalurgical structure of the steel has been impacted by the vibration and chipping of the abrasive and millions of fissures have been created separating the bonds of iron and carbon particles and undoing what beauty the blacksmith imparted in the birth of this polished hard steel.

This could be a kitchen knife or a lawnmower blade, but in the case of a shaving razor all damaged steel translates as a uncomfortable or ineffective shave. Of course we are not going to the grinding wheel with our razors, but the same type of tramatic stresses are transmitted to a finely shaped razor at the extreme edge by a diamond plate or a 1,000 grit stone. You may sharpen a blade with a progression of 1K-8K and shave with it, but I suggest that the edge will begin to desintegrate quicker than if you had inserted a 4K and a 6K in between.

The 8K above would have given you a useable shaving edge but underneath and behind that polished edge will remain the relatively damaged steel whereas the addition of the 4K and 6K would have helped to remove some of that steel allowing the final polished bevel to be based on sound firm material.

Now I agree that some very fine stones will quickly remove material and you can jump some grits and achieve a very sharp blade quickly without intermetiate steps, the temptation to accept the razor in the first initial stages of extreme sharpness will often overcome you dedication to continue working through the impacted steel. This brings me back to the durability of the edge.

Another factor of progressive grits is that in most cases your dearest stone will be your finisher, skipping steps will place more burden and wear on that stone thereby shortening its life expectancy.

In my opinion, more time spent at the stone in effective honing will result in a longer lasting edge. Alx