Video on the King Oscillator

A little while ago I wrote a post about the King Oscillator. I’ve decided to prod around a bit more, and what would you know… someone posted a video of it that gives a little more detail. More importantly, it shows how the blade move. Very instructive, if the drawings were not clear enough.

It is a short video – about one cup of coffee – so well worth watching. The same guy also have a video of using the King Oscillator, but I found that less worth watching.

Walter J Smart and the spring loaded safety razor

The safety razor was the cutting edge of shaving technology a hundred and twenty years ago. You could even say the bleeding edge, if your razor featured a replaceable blade that wasn’t quite secure… something Walter J Smart sought to fix with a trio of razor patents.

In chronological order, the patents are British patent 1905-24,010, US patent 881,033, and US patent 960,424. The all revolves around the same idea though; using a spring loaded top cap to pin the blade down. To quite from the earliest of the three, the idea was to:

…provide a razor of this character where in the blade may be easily inserted in its holder and withdrawn therefrom and which will be held accurately in place.

British patent 1905-24,010
Drawings from British patent 1905-24,010
Drawing from US patent 881,033
Drawing from US patent 960,424

As can be seen from the drawings, the basic idea is that a narrow blade is held in place by an arrangement similar in concept to the clothes pins I grew up with. The user would push the rear of the top cap down, insert a blade, and let go of the top cap. To remove the blade, the user would push down the cap and give the razor a shake. All the variations featured blade stops to prevent the blade for sliding too far forward.

I can see this design being easily adapted for most of the narrow single edge blades we use today – the various Feathers, Schick’s Prolines, injector blades… even half a DE-blade would work. And the patents are long expired, so it’s a free for all.

The patents are all available for your reading pleasure at EspaceNet and Google Patents, or alternately over at

GB 1905-24,010 (alternate)
US 881,033 (alternate)
US 960,424 (alternate)

Charles Ballreich and the very simple single edge razor

One way to make a profit selling razors in a cut throat market is lowering manufacturing costs. A way to cut cost of manufacture is to have the fewest possible parts, and the fewest possible steps. The easy way to achieve this is to design the razor to be easy to manufacture from the start, rather than trying to modify it later. You can’t get much simpler than one part and – as far as I can estimate – three steps. And that is how simple Charles Ballreich idea for a one piece single edge razor was. It is clear from the patent that ease of manufacture was a a primary objective. To quote from the introduction:

My invention relates to safety razors, and has for its object to provide an exceedingly simple, cheap, and effective safety razor, and to these ends it consists in the various features of construction and arrangement of parts adapted to co-operate in the manner substantially as hereinafter pointed out.

From US patent #855,608
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The safety razors of Benjamin Kiam

We’re all familiar with King Gillette’s early patent for the double edged safety razor, and his stroke of genius that was the simple, replaceable, flexible blade. But did you know that a very similar system was patented by Mr Benjamin Kiam at roughly the same time? A system, I might add, that had blades that would have been slightly easier to manufacture?

Mr Benjamin Kiem filed two patents on his invention, although the second one is just an improvement on the first. Looking at when he filed the patents – 1904 and 1907 – Mr Kiam was most likely inspired by the Gillette razor. The shape of the head and the use of a double edge blade is other giveaways. But while it’s interesting to see what was copied, it’s even more interesting to see what was new.

The overall design was fairly straight forward. A strong frame had the top cap as one side, and the blade and bottom plate rode on bars on either side. A bolt came up from the handle, and pressed the bottom plate and blade against the top cap. Nice, easy, and simple to grasp.

Where Gillette’s design used pins and holes to orient and secure the blade, Mr Kiem let the cutouts in the blade ride along two bars on either side of the razor head. This have several benefits. For the blade it means that instead of three holes in each blade, Mr Kiem would only have to punch a single hole hole between each blades before the continuous steel band was cut into length. For the base plate, it means no holes had to be drilled. And for the cap, no pins would have to be moulded, machined or otherwise secured. On the flip side the head is a complex shape and be hard to manufacture. As can be seen from the drawings, it would probably be easier to cast than to machine from a billet.

Or, as Mr Kiam describes the head in the patent text:

…comprising a main frame having side bars provided in their inner sides with recesses b and with projecting portions 5 and having the back plate rigid with said main frame and concaved on its inner face, the flexible blade and the guard-plate provided in their ends with notches to receive the inwardly-projecting portions 5 on the inner sides of the side bars of the main frame, and the handle provided with a screw turning through the cross-bar of the main frame and bearing against the guard plate and adapted to press the same toward the back plate, the guard-plate having a convex surface conforming to the concave surface of the back plate…

From US patent #788,318

Similarly framed heads can also be found on patents from Frank M Edmons and Thomas E McDermott – among others – but for different reasons.

Patent drawing from US 788 318
The drawing for patent US 788318
Patent drawing from US 914 957
The drawing from patent US 914,957

The main difference between Mr Kiam’s two patents is in the head. For the first patent he envisioned the frame and top cap is in one piece. In the second patent this assembly is in two parts, likely designed that way for easier manufacture. The seed for this idea is also present in the first patent, as can be seen from a careful examination of the text and drawing. His second patent also depicted square instead of round cutouts in the blade and bottom plate.

Overall I would say that Benjamin Kiam’s patents represents a very interesting road not taken… It should be possible to manufacture razors more or less to these patents today, but there would have to be quite major modifications done to make them work with modern, slotted double edged razor blades.

For those interested, both patents can be read at Google Patent; US 788,318 and US 914,957. Mr Kiem’s first patent is also available at