As I mentioned last week, the internet is a strange place. But also a fun place, if you like nerding out from time to time. The Indian Standard 7371, which I talked about last week, does of course have a companion standard. IS 7370 covers razors, safety – just as 7371 covers blades. And IS 7370 have some rather neat and potentially useful information as well.

Useful if you plan to design or manufacture your own safety razor, that is. Neat if you like this sort of things – which I do.

IS 7370 covers three types of safety razors. Separable, non-separable non-adjustable, and non-separable adjustable. Or as most people like to call them; two/three-piece, twist-to-open, and adjustable razors. They even illustrate the three kinds to make it easy to tell them apart.

Please not the complete and utter lack of cartridge razors in that lineup. Carts are inherently proprietary and non-standard, so they have nothing to do in a standard like IS 7370. Or in my shaving den, for that matter.

The standard goes into details of such things as materials used (non-ferrous corrosion-resistant metal or high-impact heat-resistant plastic) and finish. It describes acceptable lengths and diameters of the handle. It details details of the threads used, but don’t go as far as stating the size or pitch. But perhaps more interesting and/or fun, it gives exact dimensions for the blade alignment patterns. It covers pins (think Old Type style), bars (think New Type and the like) and end located (think Tech and such)

Beyond what to make razors from and the dimensions it needs to adhere to, IS 7370 also goes into details on how to do quality control. The guard needs to be parallel to the edge of the blade to within 0.15 mm, checked both by a dial gauge and by optical means.

And the manufacturer needs to clearly mark the razor with their name or trademark.

As you can see, IS 7370 – along with IS 7371 – tells you almost everything you need to know to make your own safety razor for double edged blades. The rest is “just” design, technical knowhow, and marketing.

Hmm..

Well, at least the two standards will tell you what you need to know to make sure your razor will fit almost any double edged razor blade.

You can read the whole of IS 7370 at archive.org.