Blade Sharpness Research Project

[spacemonkey42]

Lower = sharper

The number is the amount of force needed to cut a test strand, so the lower the number the less force needed, therefore the sharper the edge.

 

[purecro]

Lower = sharper

The number is the amount of force needed to cut a test strand, so the lower the number the less force needed, therefore the sharper the edge.

Thanks for the explanation, I appreciate it.

 

[helicopter]

@helicopter or anyone really, I have been reading thru this thread and looking at your index. When I see the score composition, do I assume the higher number is the sharper blade? I just want to make sure as I go thru this thread (its alot) and from this past week I am quite worn out and tired so I want to make sure I am not missing anything here. Thanks.

The index numbers represent the chronological order in which the tests were completed.

The sharpness ranking is in the image at the end of the latest test. The small vertical chart. If you click it to expand to full size, you can zoom in.

I haven't done a ranking by overall quality, best to worst, or anything like that. There are already a lot of existing lists like that, and I am not sure how much I can really do to improve them.

I will attempt such rankings at some point. There has been a lot of interest in that lately. But for now, I want to focus on measurements. And the next step will be some data cleanup. Once I have one big data table that works as a CSV, I will attempt some of this.

I had some ideas about how cutting force might be related to the subjective feeling of smoothness, but a shave with the subjectively smoother than expected Rembrandt yesterday makes me think it is probably more complicated than I previously thought.

I digress, but I believe after shaving with Rembrandt, that a specific location that is too dull to cut on the mostly sharp edge of a blade, can either catch and tug, or glide over hair, depending on how round or jagged it is, and either type of dead spot can yield the same cutting force result. The difference can probably be measured by scaling microscope pictures manually, but it probably isn't hiding in my cutting force data.

'Evenness' might be a better word than 'smoothness' to describe the variation in cutting force along an edge at different locations and a specific time in the test.

Anyway, it is something that should be quantified and also that should impact sharpness ranking, somehow.

Balance, durability, consistency of sharpness throughout the life of the blade, are all easy to quantify from cutting force data. Evenness shouldn't be too difficult, either.

In short, I want to answer the question of how sharp the blades are first, and focus on the question of objective quality later on.

 

[helicopter]

Lower = sharper

The number is the amount of force needed to cut a test strand, so the lower the number the less force needed, therefore the sharper the edge.

Oh yeah, that number. Thanks!

 

[purecro]

@helicopter Thank you for the very thorough explanation. I was a bit confused when I was looking at the charted index but when I see the graph now it makes more sense because of the blades that I see on there such as well Feather for example. I will admit though, some of the blades I have shaved with I did like myself and others do surprise me so its a very neat thing to look at. Very impressive work I have to say.

@spacemonkey42 Thanks for your explanation as well, appreciate it.

 

[helicopter]

This is the Super-Max Platinum Plus Superior Platinum blade, which was produced by Supermax PCPL in their Thane, India factory back in 2016. 90 microns thick, it is poorly balanced, and coarsely ground, but very durable and consistent.

Despite the coarse abrasives used, the transitions are fairly even, indicating significant changes in the angle at each of the three stages. The performance of the steel and coating are excellent. In the second photo, we see that after the test, the edge remained in excellent condition.

It is one of the most durable and consistent Indian blades I have tested. It isn't worth seeking out, due to the poor balance observed.

Date	18-Jan-2025			Blade Thickness, mm	0.090
Blade	Supermax PCPL	Super-Max	Platinum Plus SP	India	1-Jun-2016
Wear on Edge	0	3	6	9	12
Edges Measured	Bottom / Top	Bottom / Top	Bottom / Top	Bottom / Top	Bottom / Top
Measurement Medium	Stren 4 .21	Stren 4 .21	Stren 4 .21	Stren 4 .21	Stren 4 .21
Dulling Substrate	New	Paper	Paper	Paper	Paper
Measurements	20	20	20	20	20
Adj. Std. Dev.	15	14	13	7	10
Median F (g)	53	55	56.5	54.5	60
Mean F (g) Top	49	52	52	52	53
Mean F (g) Bottom	67	64	64	59	64
Mean F (g)	58	58	58	55	59
BESS Adj. Factor	1.39	1.39	1.39	1.39	1.39
Avg. Adj. F (g) Top	68	72	72	72	74
Avg. Adj. F (g) Bottom	94	90	90	82	90
Median Adj. F (g)	74	76	79	76	83
Mean Adj. F (g)	81	81	81	77	82

Blade Sharpness Test Index

 

[Beto Salatini]

Congratulations on your magnificent work, my dear @helicopter

Cheers!

 

[abies]

I have to say I'm a bit skeptical of the idea that blade quality can be reduced to a single number after seeing these results. It seems like it would depend on what a person is looking for, not to mention coatings and so forth? Even the way in which the blade wears seems probably related to its feel and so forth.

 

[abies]

This is the Rimei Stainless Steel Platinum 2300 blade, which is made for the Chinese market and marked with an address in Foshan, Guangdong, China. It is hard to say, but it looks like a Carlife blade to me, although Kinghood and Ying Jili are the manufacturers I know of in Foshan City. Like a lot of Carlife blades, it mentions the US on the package. The Apache I tested was 102 microns, and could possibly be made with American 0.004" steel. This blade is made from 100 micron steel, fairly sharp, with excellent balance and durability and reasonably good consistency. It has a persistent coating so sharpness peaks after the second paper cut test.

This doesn't have a flap tuck like Apache, but the rest of the tuck die is pretty similar.

View attachment 1978477 View attachment 1978478 View attachment 1978479

It is a World class grind; even stria, even transitions, everything looks clean. In the second photo, we see that after the test, the failure mode of the steel was some small chipping. The grind is more like Carlife and Kinghood than Ying Jili.

View attachment 1978480View attachment 1978481

It is either a platinum or advanced ceramic driven metallic coating, and in this regard, does not resemble the Carlife Apache blade I tested previously. Performance is closest to the Xirui Rhinoceros. It is not very common in the US, and though there are some possibilities mentioned, it is hard to say who makes it. Rimei might even produce their own blades. Maybe one of you can tell me.

It is a blade of good quality, though not one many Western enthusiasts are using, perhaps because the street price of around $15/100 isn't competitive with similar blades like Rhinoceros XR.

View attachment 1978622

Date	16-Jan-2025			Blade Thickness, mm	0.100
Blade	Rimei	Rimei	SS Platinum 2300	China	1-Jan-2024
Wear on Edge	0	3	6	9	12
Edges Measured	Bottom / Top	Bottom / Top	Bottom / Top	Bottom / Top	Bottom / Top
Measurement Medium	Stren 4 .21	Stren 4 .21	Stren 4 .21	Stren 4 .21	Stren 4 .21
Dulling Substrate	New	Paper	Paper	Paper	Paper
Measurements	20	20	20	20	20
Adj. Std. Dev.	7	8	6	8	9
Median F (g)	52	46	43	47	51
Mean F (g) Top	50	45	46	46	53
Mean F (g) Bottom	55	51	41	48	50
Mean F (g)	52	48	44	47	51
BESS Adj. Factor	1.39	1.39	1.39	1.39	1.39
Avg. Adj. F (g) Top	69	62	64	64	74
Avg. Adj. F (g) Bottom	77	71	57	67	69
Median Adj. F (g)	72	64	60	65	71
Mean Adj. F (g)	73	66	61	66	71

View attachment 1978621 View attachment 1978620

Blade Sharpness Test Index

So I got interested in this Rimei blade, and in poking around it seemed suggested that this blade might be made in the US, which would imply Accutec? Does that even make sense?

It would be odd in some kind of weird reverse outsourcing way, but that does happen occasionally. I guess what I'm wondering is if the blade looks like a US Personna or Accutec, or something they might make to some spec for some reason.

It does seem hard to find in the US; I can only find a few sources for the brand, and I'm not even sure if they're carrying the same blade (some are labeled "super stainless" and others just "stainless", although the packaging for each looks very similar).

 

[helicopter]

I have to say I'm a bit skeptical of the idea that blade quality can be reduced to a single number after seeing these results. It seems like it would depend on what a person is looking for, not to mention coatings and so forth? Even the way in which the blade wears seems probably related to its feel and so forth.

I would generally define quality as having the things consumers are looking for, and there is no doubt blade consumers are looking for different things. In this sense, I agree with your assessment. It may be not much more useful than an Amazon star rating.

What I meant in this case was how well the product measures against some reasonable objective ideal, such as perfect balance, or perfect eveness, perfect consistency, or perfect durability. How far are the 100 cutting force measurements from being of the same value in all of these senses? How about ten blades from the same manufacturer?

We can quantify how well these things are controlled. I am confident I can demonstrate that Treet blades are more likely to do again what they did before compared to Samah blades, for example. That is my intent.

If you are recommending a blade for someone who likes mild blades to try, would you want to recommend one that you can't say with any reasonable confidence, about how sharp the one they actually get is going to be? What if they like it and want to order another 500 that perform the same as the one in the sample tuck? Would you want to recommend one that is usually about 15% sharper on one edge than the other?

Ultimately your subjective experience will determine what you like, and is all that matters, but that doesn't mean evey blade is equally worthy of a trial. It doesn't mean ther are no bad blades. It doesn't mean there are no good blades.

You mention coatings. They change measured sharpness too. Lubrication of a cutting edge isn't something that happens out in an ether where it can only be felt and not tested.

There is this religiosity in the broader shaving community around this false assertion that everything is subjective. In truth, there is a big objective component. It certainly benefits retailers that people espouse it, and it can't be refuted based on anecdotal evidence.

It is foolish to throw shaving gear at the wall and wait to see what sticks. Sure, it will get you to the same end eventually at much greater effort and expense. Just because everyone in shaving gives everyone else the same bad advice all the time doesn't make them all right. Truth is not democratic. Things that are measurable like sharpness are not democratic.

I am not planning to attempt to quantify everything, but I can definitely quantify enough to recommend dismissing certain products and trying others. I am already doing that now, just not in a way that uses the data I have to its fullest.

 

[helicopter]

So I got interested in this Rimei blade, and in poking around it seemed suggested that this blade might be made in the US, which would imply Accutec? Does that even make sense?

It would be odd in some kind of weird reverse outsourcing way, but that does happen occasionally. I guess what I'm wondering is if the blade looks like a US Personna or Accutec, or something they might make to some spec for some reason.

It does seem hard to find in the US; I can only find a few sources for the brand, and I'm not even sure if they're carrying the same blade (some are labeled "super stainless" and others just "stainless", although the packaging for each looks very similar).

It is not made in the US, but assuming it's a Carlife blade, it has a history of shared information and standards with ASR, the Verona Virginia company that evolved into the Accutec we have today. There were Personna branded Carlife blades at one point in time. I suspect some Carlife blades were or are even made of American steel, but not the Rimei I just tested.

 

[abies]

I would generally define quality as having the things consumers are looking for, and there is no doubt blade consumers are looking for different things. In this sense, I agree with your assessment. It may be not much more useful than an Amazon star rating.

What I meant in this case was how well the product measures against some reasonable objective ideal, such as perfect balance, or perfect eveness, perfect consistency, or perfect durability. How far are the 100 cutting force measurements from being of the same value in all of these senses? How about ten blades from the same manufacturer?

We can quantify how well these things are controlled. I am confident I can demonstrate that Treet blades are more likely to do again what they did before compared to Samah blades, for example. That is my intent.

If you are recommending a blade for someone who likes mild blades to try, would you want to recommend one that you can't say with any reasonable confidence, about how sharp the one they actually get is going to be? What if they like it and want to order another 500 that perform the same as the one in the sample tuck? Would you want to recommend one that is usually about 15% sharper on one edge than the other?

Ultimately your subjective experience will determine what you like, and is all that matters, but that doesn't mean evey blade is equally worthy of a trial. It doesn't mean ther are no bad blades. It doesn't mean there are no good blades.

You mention coatings. They change measured sharpness too. Lubrication of a cutting edge isn't something that happens out in an ether where it can only be felt and not tested.

There is this religiosity in the broader shaving community around this false assertion that everything is subjective. In truth, there is a big objective component. It certainly benefits retailers that people espouse it, and it can't be refuted based on anecdotal evidence.

It is foolish to throw shaving gear at the wall and wait to see what sticks. Sure, it will get you to the same end eventually at much greater effort and expense. Just because everyone in shaving gives everyone else the same bad advice all the time doesn't make them all right. Truth is not democratic. Things that are measurable like sharpness are not democratic.

I am not planning to attempt to quantify everything, but I can definitely quantify enough to recommend dismissing certain products and trying others. I am already doing that now, just not in a way that uses the data I have to its fullest.

I agree about demystifying blade characteristics. I guess I feel like there's a trend — maybe it's always been this way in this thread but I can't tell — of people wanting a single ranking of blades, and I guess if that's what they want, such a thing can be produced. But to me much of what you might want to know from the information of this project's type is in there already, and more richly so.

For me personally, for instance, my favorite blades have not always been the sharpest (although most of them have been), and I might have missed out on some blades by just going down a list of blades ranked by sharpness. Some of the blades that I have tried that are ranked more sharp I have really disliked and others less sharp I have liked more.

I realize sharpness isn't all that's in these numbers, but I do still have a sense that the formula predicting subjective impressions is maybe sort of complex and varies from person to person.

To do it "right" I'd think you'd almost have to have a large number of people use a large number of the blades and rate them, and then figure out if there are patterns to preferences (someone who likes A also tends to like M, and someone who likes F also tends to like R), and what predicts those patterns of preferences. Even then you'd have batch to batch variation, user mismemory and so forth.

Maybe it's just that I think this database and resource is incredibly useful and feel like reducing it to a single number, or even a couple of numbers, wouldn't do it justice.

 

[helicopter]

Thanks. I will try not to ruin it. If it doesn't look like it will be useful and objective, I will put it in another thread.

 

[helicopter]

This is the New Superior Quality Vidyut Super-Max Superior Stainless Economy Pack red blade, which was made by the Thane Super-Max PCPL in 2016, most likely in their Kandla Vidyut Metallics factory. It is an extra-thin 85 micron blade, mild in sharpness, with excellent balance, and typical durability and consistency. Despite the 'Stainless' moniker, I believe it has a platinum driven metallic coating. I think this individual blade is probably an excellent representation of the specification. The plastic wrap has symmetrical folds on the ends, and it has batch codes and dates on it.

It looks like something from Vidyut Metallics Kandla, with the coarse and uneven stria, and errant stria. In the second photo, we see that the failure mode of the steel was lots of large denting and shipping, which isn't unusual with such a thin blade.

It looks an awful lot like the Vidyut Super-Max Platinum blade in performance. That one was a Middlesex blade of 95 microns, but I bet it was made with the same alloy and grind. 100 micron middlesex Dollar Platinum, 90 micron Tigaksha RK Chrome, and RK Stainless also have very similar performance. The blue box Vidyut Super-Max Super Stainless was a milder 90 micron Middlesex blade, but probably shared some characteristics as well. All of these Middlesex and Thane blades were probably made in the Kandla Vidyut Metallics plant. I believe I was mistaken about that detail in the previous test.

These blades weren't bad for $6/50 at Maggards, but I am not going to tell everyone to run out and buy them, either. The new and current RK blades of similar design are perfectly good substitutes.

Date	18-Jan-2025			Blade Thickness, mm	0.085
Blade	Super-Max PCPL	Vidyut Super-Max	Stainless Econ	India	1-Nov-2016
Wear on Edge	0	3	6	9	12
Edges Measured	Bottom / Top	Bottom / Top	Bottom / Top	Bottom / Top	Bottom / Top
Measurement Medium	Stren 4 .21	Stren 4 .21	Stren 4 .21	Stren 4 .21	Stren 4 .21
Dulling Substrate	New	Paper	Paper	Paper	Paper
Measurements	20	20	20	20	20
Adj. Std. Dev.	11	9	20	17	22
Median F (g)	58	56	57.5	63.5	66.5
Mean F (g) Top	58	60	68	72	77
Mean F (g) Bottom	60	54	54	57	63
Mean F (g)	59	57	61	64	70
BESS Adj. Factor	1.39	1.39	1.39	1.39	1.39
Avg. Adj. F (g) Top	81	83	95	100	107
Avg. Adj. F (g) Bottom	83	76	76	79	88
Median Adj. F (g)	81	78	80	88	93
Mean Adj. F (g)	82	79	85	89	98

Blade Sharpness Test Index