How can a leather strap sharpen a barber's razor?

how can a leather strap sharpen a barbers razor?

The strop does not sharpen the razor. Straight razors are sharpened by honing just like any knife. The Barber's strop smooths the edge.

I've been fascinated with straight razors ever since I went to a barber who when I asked him to block it off in back pulled out a straight razor and used it to shave the back of my neck. I got my grandfather's straight razor and have experimented with it. I can shave without knicking myself up though I never managed to get as close a shave as I can with a modern safety razor.

When you shave, the cutting edge gets somewhat misaligned microscopically. It looks like microserrations, bending aside irregularly. After 3 or 4 shaves it should be aligned a little bit again and therefore you must strop. If you do that correctly, and treat the blade well, you only need to hone once every month or even year, and never send it in for grinding.

You need the right strop and the right paste. The game is, to postpone honing as long as possible, and to use the strop almost exclusively. Stropping occurs at the exact same angle as with honing. Stropping serves to polish the edge and to align any remaining mislalignment of the microserrations.

You can to the same with a pocket knife and a slooth leather belt try it after sharpening with the belt wet your arm and save away. . .

Nowadays, a barber's razor is sharpened using a micro groove, known as 'getting your groove on'.

In the past they used to use a leather strap - when the barber's razor became blunt you would hear people say 'Oi! Get your strap on', or just 'Get your leather strap on'.

It is a little known fact that barbers (and some hairdressers) must follow an ancient code which states that if a customer says to them 'get your leather strap on', then they must give that customer a free haircut.

Hope this answers your question