I am seeing snake oil salesmen out there… money for nothing… pays for itself… Bunch of rubbish.
The one I’ve spotted recently is the “cartridge razor sharpener!”
Yes, this device can actually sharpen your expensive cartridge razor blades…. and no doubt will make you rich, able to fly and speak 15 languages fluently… at the same time.
You see, a cartridge style razor cannot be sharpened properly.
The reason is this:
Unless you sharpen a blade on both sides (so as to match the original blade angle), you alter the geometry – which is a mute point as you cannot get to the back of a cartridge blade without taking the cartridge apart and removing the blades….
If you did manage to sharpen the blade and retain geometric integrity, you still alter the dimensions. If you sharpen something, it gets shorter. The only way to keep the gap between the blade rows optimal is to remove each blade, profile it, sharpen it, then re-seat it in a new position!
The other key point is that modern blades have composite materials to give strength and flex. If you sharpen an edge you remove the coating. E.G: A hard micrometre thick external coating gives a sharp cutting edge. An underlying softer material allows for a flex and contour following blade.
If you sharpen that blade post manufacture, you end up removing the edge that does the cutting & are left with a soft, rapidly blunting, flexible metal strip.
NOTE: Composite doesn’t mean carbon fibre or Kevlar etc! It means it is made up of several materials or compounds. E.G: A chrome effect phone is a composite of the plastic phone body and the chrome effect surface. A pencil is a composite of the graphite core and the wooden body.
Sure, there is a way to re-life cartridge blades – but for all the effort involved in stripping the cartridge, symmetrically lapping the blades, remodelling the body to hold the changed blades, re-plating the sharpened blades (and buying all of the machinery & tools to do this), then it’s better off for you to just buy a new cartridge.
It’s engineering fact.