From ShaveWiki

Contents 1 Aggression 1.1 Ranking by blade gap size 1.2 Table of blade gaps 1.3 Aggressiveness and Exposure

Aggression

Aggressiveness is not dependent upon a single dimension or measure of a razor. It depends upon blade geometry/angle, exposure, span, gap, weight, and most of all, the user.

Again: there are factors other than the blade gap size that might make a razor seem more or less aggressive. Most notable is "blade exposure", or, the protrusion of the blade above a line tangent to the razor head and blade guard as they touch the face (see picture for more information and terminology).

Ranking by blade gap size

The following, while based on a measurement of blade gap and razor weight, will hopefully agree with most of the impressions of the shaving community. This list was compiled by multiple people; inaccuracies are bound to result, and therefore multiple listings for the same razor are possible and even desirable. If there is only one measurement of a given razor gap, it assumes very strict manufacturing tolerances and that the razor measured has not ever been dropped, etc. which we know to not be the case.

The easiest way to measure the blade gap is with a feeler gauge. How to do it is described here.

Table of blade gaps

Blade gap, in 1/1000's of an inch [ +/- .001 inch ]

List order: Smallest gap size (mildest) to larger (more aggressive)

Blade gaps, ranked by gap size

thousandths of an inch	millimeters	Razor	weight, grams
15		Merkur Progress 570 @ 1
17	.43mm	Gillette Adj Black handle @ 1	Long Handle, 67
18	.46mm
19	.48mm	GEM 1912
20	.51mm	Ming Sui
		Gillette Rocket (UK)
21	.53mm	Gem Micromatic
		Gillette New Improved Tuckaway
		Schick Krona
22	.56mm	Gillette Adjustable @ 1
		Gillette New Norfolk
		Gillette TECH	Fat Handle, 48
		Merkur Classic
		Weishi
		Merkur Progress 570 @ 2
23	.58mm	Gillette NEW	Ball-end, 54; square end, 51
		Gillette Super Speed (Blue Tip)	45
24	.61mm	Gem G-Bar
		Gillette Adjustable @ 2
		Feather Popular
25	.64mm	Gillette Aristocrat (US)	late 1940s, 69
		Gillette Knack	43
		Gillette Ranger Tech
		Gillette Super Speed (black handle)
		Gillette Super Speed (late 1940s)	54
		Merkur HD Long Handle (38C)
		Wilkinson Croma
		Schick Injector Type L
		Merkur 23C
26	.66mm	Bic Disposable (orange handle)
		Gillette Adjustable @ 3
		Gillette Aristocrat (UK)
		Gillette Super Speed Red Tip (US)	65
27	.69mm
28	.71mm	Merkur HD (34C)	78
		Merkur Progress 570 @ 3
29	.74mm	Gillette Adjustable @ 4
30	.76mm	Muhle R-89/ Edwin Jagger DE89L
31	.79mm	Feather Portable
32	.81mm	Gillette Adjustable @ 5
		Bic Metal
		Gillette Super Speed Red Tip (UK)
33	.84mm	Merkur Progress 570 @ 4
34	.86mm
35	.89mm	Gillette Adjustable @ 6
36	.91mm
37	.94mm	Merkur Progress 570 @ 5
38	.97mm	Gillette Adjustable @ 7
39	.99mm
40	1.02mm
41	1.04mm	Gillette Adjustable @ 8
		Gillette Adjustable (black handle) @ 9
42	1.07mm
43	1.09mm
44	1.12mm	Merkur Futur @ 1	120
45	1.14mm	Gillette Adjustable @ 9
47	1.19mm	Merkur Futur @ 2	120
53	1.35mm	Merkur Futur @ 3	120
58	1.47mm	Merkur Futur @ 4	120
63	1.60mm	Merkur Futur @ 5	120
65	1.65mm	Merkur Futur @ 6	120
69	1.75mm	Merkur Futur @ 6 .5	120
?		Butterscotch Schick Injector	31
?		Lux	56
?		Stahly Live-Blade	164
?		1953 Gillette Super Speed	56
?		1952 Gillette Super Speed	42
?		1959 Gillette Super Speed	55
?		1956 Gillette Super Speed	58

Note: Gillette Adjustables - Slim and Fat Boy range from .022 @ 1 to .045 @ 9; Fat Boy (195) weighs 79 gm, Slim Adjustable weighs 70 - the Black handle Adjustable ranges from .017 @ 1 to .041 @ 9 or 1 setting smaller than the Slim or Fat Boy - Merkur Slant has a slightly variable blade gap, and is difficult to measure; it weighs 76 gm.

Subjective differences in ranking were limited to +/- .001 measurements so differences of .001 - .003 can be considered functional equivalent.

Aggressiveness and Exposure

Aggressiveness of a safety razor can be thought of as the degree to which a blade is exposed to the face and beard, or conversely the degree to which the face and beard are not protected from the blade by the razor's safety features.

The two things that protect your face and beard from the blade are the razor's cap and the razor's guard. The cap and guard touch the skin while shaving and the blade is exposed to the skin between the two. Thus, the blade exposure can be described as the distance the blade protrudes past an imaginary tangent between cap and guard. The "gap" discussed above is not the same as the exposure as defined here, but larger gaps will tend to create larger exposures, given that the rest of the geometry stays about the same. So, the above measurements do give an approximate ranking.

Another factor in aggressiveness might be the angle that the blade makes with that imaginary line. There is probably an ideal angle but that might be different for different beards and maybe even different for different areas of the same beard.

One advantage of an aggressive razor may be that the user has more control over the angle at which the blade touches the skin.