Thread: proper included angle

Can anyone clue me in as to what sort of included angle a straight razor should have at the edge? (I understand that it varies, so rough ranges would be more than good enough.) Industrial razors are often in the 30 deg. range, so I'm assuming that it's a fair bit under that.

Cheers.

~ Karl

My vote would go for 16 +- 3 degrees, there lots of variables.

Here is a thread.

http://straightrazorpalace.com/razor...zor-angle.html

Charlie

The consensus among those who know is somewhere in the range of 16 to 18 degrees.

feather blades are at 22degrees per Tim Zs study
and i have had nothing but problms when running at under 14 degrees

hows that for a range

Hey, thanks guys.

I'd tried searching a few times, but hadn't found that page yet.

I used to work in an industrial testing lab, so my fallback plan would be to measure mine, but it's nice to see a variety.

BTW - I'm not on here often, but accurate measurement and metallurgical funkybusiness are some of the few things that I do actually know a useful amount about. I'm always happy to chat about that stuff.

I doubt manufacturers actually measured the angle… but throughout the history of making razors, most (if not all) manufacturers adhered to the proportion of the blade about 3.5 times the thickness of the spine.

So for example: 4/8th would be bit over 1/8th inch spine, 5/8th would be 3/16th inch spine, 6/8th razor would be a bit under ¼ inch spine, 7/8th to 8/8th razor would be about ¼ inch or more spine thickness.

They would start with a bar of steel about the width of the spine of the finished razor (I guess 3/16th and ¼ in thickness was the common sizes of steel supplied in those days), and simply forge the blade a bit more than the desired width, then after grinding, finishing and sharpening the razor would be somewhere about right.

But as you can well understand, “early” razors were all forged and ground by hand, and variations will occur, so there may not be a precise figure for the angle. However, as manufacturing techniques became more modern and efficient… they still stuck to the 1 to 3.5 proportion... because it worked.

I doubt manufacturers actually measured the angle… but throughout the history of making razors, most (if not all) manufacturers adhered to the proportion of the blade about 3.5 times the thickness of the spine.

Thank you! I can work with that --

with a blade that's 3.5x as wide as the spine,

the included angle is 16.3 degrees.

[The arithmetic:
the thickness is 1/3.5 of the blade width, so
the half-thickness is 1/7 of the blade width, so
the half-angle is arctan (1/7) = 8.13 degrees, and

the angle is 16.26 degrees.

Charles

Originally Posted by cpcohen1945

a blade that's 3.5x as wide as the spine

It is the golden razor ratio if there ever was one

Yes, but imagine a circle with centre in the middle of the blade with radius Z (Z to the spine and Z to the edge).

Now, if we place this imaginary circle around the blade and now imagine that it is a disc of height A, we can work out the volume of this encompassing disc as follows:

Volume = area X height

Area of a circle is Pi X (radius squared), which is, in our case,

Pi x Z x Z

So the Volume must be

PiZZA!

Ergo, when thinking of the best angle for a razor, it is best to have a pizza.

Math don't lie.

James.

Should the pizza be 3.5 x as wide as it's crust?