Blade Sharpness Research Project

[Pinto90]

I really enjoy these blade test because he answers a lot of questions that nag at me. Like a splinter in the back of my mind, to quote Morpheus.

The test between pre and post June, 2020 Wizamets was a good example.
Your previous post brings up another:

View attachment 1885278

The blades on the right. I've seen multiple claims that they're made in Israel but no proof. Yes, they probably are but there is nothing, zilch, nada on the box or tuck to indicate where they were made, just
Superior Technology from American Safety Razor Co., USA.
My Israeli Reds say Blades made in Israel right on the tuck and hanger. Yes, they may very well be the same blade/steel/grind but a test could answer that definitively.

So for me, that is one of the great side benefits of the tests and tedious work Dan is doing here and I hope I'm speaking for all of us by saying...
Thank You!

Are the new blades the ones in the package on the left?

Personally I would judge the package on the left to be older than the other packages on the right.

 

[Ron R]

@lasta Re: wire edge

Way back when I first joined B&B, I borrowed a microscope to see why the BIC CP blades I bought felt like barbed wire. I didn't take nearly as good of photos as Helicopter is getting - but this is what I was finding on that batch of BIC blades, this is not a hair - it is a piece of the wire edge that should have been stropped off but was left hanging. You couldn't brush it off - but running the edge thru a cork would pull it off. I later bought another batch of BIC CP that were good. I don't think these bad ones were counterfeit, just a bad run that should have been caught by QC.
View attachment 1884870

I remember when fellows would give me doubt when I rated my Bic blades at the bottom of my small collection of blades and I maybe got some tucks like these photo's shown, they just seemed a little unpredictable to shave with, one shave would be great and the next not so good(they seem to not wear in a similar wear pattern to other great blades when slowing dulling over time) . Thanks for the photo above- open attachment for photo reference!.
They must of missed this on their QC checking system IMO.

Have some great shaves!

 

[Sweeney_]

Are the new blades the ones in the package on the left?

Personally I would judge the package on the left to be older than the other packages on the right.

I'm fairly certain the one on the left is the newest because that box is still widely available through sellers. There is also another one that looks almost identical but lacks the graphic at the top right of the box with the German flag colors which may be an earlier version. The box on the right is likely the oldest since they can no longer be found (at least I can't) through sellers or the auction sites. I purchased those in August, 2022 and even then, they were getting more difficult to locate.

 

[helicopter]

Today, I answer the lingering question about the German Personna in a plastic tuck of ten blades as well as we can.

This is another one the @Sweeney_ generously offered for testing. This blade comes in a white plastic tuck of ten blades.

It is single -wrapped in strong waxed paper with some big wax dots.

There isn't any useful production information on the tuck, and there aren't any grind numbers on the blade, but we do get decent printing of the brand and blade.

It looks like the red one.

After the test, it looks like the red one did after the test, except this individual edge is in worse condition. I tested both edges of three blades from this batch, one on my face, and two with paper. This was the weak edge on the duller of the two paper tests. The other edges are more similar to the red one I looked at in terms of chipping, where this one shows significant wear and even some dead spots.

Information Summary:

I tested two of these, because the first one had one bad edge and I wanted to see if the whole batch was like that. Then I shaved with a third one and measured it.

We see some variation, but it is the same blade. One of the Blue/Whites is more similar to the Red than it is to the other Blue/White from the same batch. The dead spots, since they show up in data sporadically after P6-12 on some of the edges tested, put some randomness into the information that increases as we progress through the testing procedure.

Date	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24
Blade	Personna Platinum	Platinum Chrome	59.a	Germany
Shaves	0	P3	P6	P9	P12
Location	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top
Medium	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29
Dulling Substrate	New	Paper	Paper	Paper	Paper
Measurements	30	30	30	30	30
Std. Dev.	13	26	61	61	60
Median F (g)	78	71	80.5	80	93
Mean F (g) Btm	76	69	75	76	79
Mean F (g) Top	83	101	137	140	159
Mean F (g)	80	85	106	108	119
BESS Adj. Factor	0.83	0.83	0.83	0.83	0.83
Av. Adj. F (g) Bt	63	57	62	63	66
Av. Adj. F (g) Top	69	84	114	116	132
Median adj. F (g)	65	59	67	66	77
Mean adj. F (g)	66	71	88	89	99

The one I shaved with has the same big top edge to bottom edge variance as the others. Knowing it was there, it was very easy to detect while shaving, and fun to be able to swap back and forth. I like the sharp edge better everywhere on my face, but the difference it makes depends a lot on the hair and skin. On my full but not dense cheeks, it doesn't really matter and is just something I can tell is there. On my chin, which is dense and coarse, but has tough skin, it is extremely easy to detect, but doesn't matter a lot because pulling through that part doesn't really hurt my face either way. On my looser neck hair, the dull edge is a bit annoying and leaves a lot more stubble. On my mustache, which is coarse, dense, and sensitive, it is enough difference to change the experience from acceptable but not great to something uncomfortable enough that I wouldn't keep using the blade. Of course, I was able to flip the razor around easily enough to deal with this.

Date	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24
Blade	Personna Platinum	Platinum Chrome	59.b	Germany		59.c
Shaves	0	P3	P6	P9	P12	1
Location	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top
Medium	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29
Dulling Substrate	New	Paper	Paper	Paper	Paper	Face
Measurements	30	30	30	30	30	30
Std. Dev.	11	19	46	37	65	13
Median F (g)	74.5	71.5	77	84	91	72
Mean F (g) Btm	74	77	112	108	149	77
Mean F (g) Top	79	81	82	91	85	67
Mean F (g)	76	79	97	99	117	72
BESS Adj. Factor	0.83	0.83	0.83	0.83	0.83	0.83
Av. Adj. F (g) Bt	61	64	93	90	124	64
Av. Adj. F (g) Top	66	67	68	75	70	55
Median adj. F (g)	62	59	64	70	75	60
Mean adj. F (g)	63	66	81	82	97	60

Mystery solved. There is a small chance of some unimportant difference, but most of the difference we see is batch variation, which seems to be alright, but not extremely well controlled for this facility. If you have both of them and find them to be different, they probably are, because the batches are inconsistent enough to notice. I believe it is made to the same or nearly the same specifications from the same or nearly the same materials.

Blade Sharpness Test Index

Complete Data

 

[Sweeney_]

@helicopter I commend you for removing that splinter from the back of my mind.

Case closed. I salute you sir. 🫡

 

[helicopter]

This afternoon, I checked the unknown Personna Platinum blade that was generously provided by another member. Unfortunately, I was unable to solve this one. It doesn't closely resemble any of the blades tested so far. It comes in a white plastic tuck of ten blades. It was produced May 15, 2019 according to the date code "9 135" on the side of the tuck.

The individual blades are single wrapped in thick wax paper, and there are no wax dots. The stenciling on the blade is the same as the German and Israeli ones.

The edge of the new blade is most similar to the American blades tested. The coating looks most like the current American Accutec blade, and second most like the Older American Energizer. The Israeli and German blades tested have a heavy coating. The primary grind looks the same as both American blades; coarser than the German or Israeli ones. The secondary grind and honing, covering about 40% and 10% of the bevel, are nearly identical to the Energizer. The other blades tested have a more distal secondary grind, but similar honing.

After the test, there is some small chipping, the coating has worn, and the bevel is smoother.

Information Summary:

I did the complete testing procedure on one blade, and did an abbreviated test on another to check for variation. The first blade doesn't closely resemble any of the other blades. The second blade closely resembles the Energizer. If it were not for the stenciling and the rumor that this blade is Israeli, I would probably think it was American. As it is, I am not drawing any conclusions. I wouldn't even be shocked if it were German. Perhaps a blade that matches it better and has a country of origin printed somewhere will come across my desk at some point in the future.

The blades were fairly similar. The second one was a bit sharper, especially before the first paper cut.

Date	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24
Blade	Personna Platinum	Platinum Chrome SSS	ASRC Ever-Ready		May 15, 2019	60.6	60.6	60.6
Shaves	0	P3	P6	P9	P12	0	P3	P6
Location	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top
Medium	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29
Dulling Substrate	New	Paper	Paper	Paper	Paper	New	Paper	Paper
Measurements	30	30	30	30	30	20	20	20
Std. Dev.	14	13	16	22	26	10	11	16
Median F (g)	86.5	76	76	87	96	82.5	77	77
Mean F (g) Btm	89	80	82	85	93	84	76	77
Mean F (g) Top	86	79	84	98	113	78	80	88
Mean F (g)	87	80	83	91	103	81	78	82
BESS Adj. Factor	0.83	0.83	0.83	0.83	0.83	0.83	0.83	0.83
Av. Adj. F (g) Bt	74	66	68	71	77	70	63	64
Av. Adj. F (g) Top	71	66	70	81	94	64	66	73
Median adj. F (g)	72	63	63	72	80	69	64	64
Mean adj. F (g)	72	66	69	76	86	67	65	68

Blade Sharpness Test Index

Complete Data

 

[Flanders]

Well, this would fit with a narrative that while transitioning to the German plant, they temporarily had the US plant supply blades in the left over packaging from Israel. I say narrative as this wasn't even on my Personna bingo card!

 

[helicopter]

I tested another popular white label Chinese blade from Amazon, the Shaving Revolution Platinum Series Japanese Stainless Steel blade. It looks like performance should be fine, but nothing here justifies the price of $9.88 for 50 blades.

The outer box is nice.

The blade outline looks the same as the RK blades Henson is importing from India.

Double wrap. No wax.

The stenciling looks nice.

The grind and coating look alright. They are both a bit uneven, but nothing that should be detrimental to performance or blade feel.

This chipping at the edge after testing is typical of razor steel.

It is fairly mild in sharpness, and very consistent.

Date	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24
Blade	Shaving Revolution	Platinum Series	Japanese Stainless	Chine	~2023
Shaves	0	P3	P6	P9	P12
Location	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top
Medium	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29
Dulling Substrate	New	Paper	Paper	Paper	Paper
Measurements	24	24	24	24	24
Std. Dev.	15	13	24	12	18
Median F (g)	88.5	77	84.5	92.5	87.5
Mean F (g) Btm	94	80	86	93	88
Mean F (g) Top	82	82	90	89	96
Mean F (g)	88	81	88	91	92
BESS Adj. Factor	0.83	0.83	0.83	0.83	0.83
Av. Adj. F (g) Bt	78	66	72	77	73
Av. Adj. F (g) Top	68	68	74	74	79
Median adj. F (g)	73	64	70	77	73
Mean adj. F (g)	73	67	73	76	76

Blade Sharpness Test Index

Complete Data

 

[helicopter]

I tested the PearlMax, which is a Chinese blade and brand. It is another moderately sharp blade of good durability and consistency.

It comes in a five blade tuck with holographic foil on it. The individual blade is single wrapped in nicely printed heavy paper with no wax dot. The printing on the blade looks typical.

It has a medium grind and a honed edge with moderate and reasonably even distal coating.

The edge is barely changed with testing. THe coating is worn a bit, and the bevel is a bit smoother.

It is moderately sharp with excellent consistency.

Date	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24
Blade	PearlMax	Super Platinum	Super Stainless	China	~2023
Shaves	0	P3	P6	P9	P12
Location	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top
Medium	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29
Dulling Substrate	New	Paper	Paper	Paper	Paper
Measurements	24	24	24	20	20
Std. Dev.	9	7	9	8	8
Median F (g)	86	83.5	85	88.5	86.5
Mean F (g) Btm	91	86	89	92	91
Mean F (g) Top	80	82	80	83	84
Mean F (g)	86	84	84	87	88
BESS Adj. Factor	0.83	0.83	0.83	0.83	0.83
Av. Adj. F (g) Bt	76	71	73	76	76
Av. Adj. F (g) Top	67	68	66	69	70
Median adj. F (g)	71	69	71	73	72
Mean adj. F (g)	71	69	70	73	73

I have done abbreviated tests on these last two blades, with 112 cuts instead of the usual 150. This saves me a decent amount of time, so I am probably going to keep the change for most blades, and keep the 150 cuts for blades I consider to be especially important. Just in case there is some difference in blade wear from the measurement, I am going to switch media again soon. I had some concern when I saw how consistent these two blades were in the tests.

I prefer to wear the blades on the paper and minimize the impact of measurement on the edges, so I am going to test some thinner media this week. It's not a big concern, and I believe the tests with 0.29mm media are comparable to those done with BESS media, but I also think the that if I am not doing the same number of cuts on every edge, I should reduce this factor as much as practical, and I had excellent results with slightly smaller 0.27mm media in earlier testing.

I ordered 2 km of 6-lb test line, so wish me luck in getting good performance from it. I will need to pick a different point for defining a dead spot and capping force as well. I will probably base that on one standard deviation above the mean for the Flying Eagle Carbon Steel blade with some rounding to keep it simple down the line. I will need the media here to work that part out.

Blade Sharpness Test Index

Complete Data

 

[helicopter]

The Dorco New Platinum STP-301 Stainless blade is made in Vietnam under license from the Korean company. It is a blade of exceptional sharpness, the fifth sharpest tested so far, and it is reasonably durable and consistent. It appears to be made of tough and resilient steel. I am sure everyone at Dorco would be proud of the fact that this blade is sharper than any Russian or Chinese blade I have tested so far.

Thankfully, I still have 99 of them left.

It comes in plastic tucks of ten blades, which are individually wrapped in printed waxed paper with no dots. The only things missing are a date code and alloy. I don't know why anyone wouldn't share the alloy, as it is something that is very easy for their competitors to check anyway with an XRF metal analyzer.

The blade has nice printing.

It has a coarse and uneven grind, with a honed edge, and a heavy distal coating.

After testing, we see the edge is in excellent condition with some small dents and no chipping. I am surprised they got such a tough steel to stay so sharp through the test. This is excellent steel. The curved scratch lines on the primary bevel make me wonder if the edge is an S-grind or concave grind as well. Advanced edge geometry may partly explain this blade's exceptional performance overall.

Information Summary:

Date	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24
Blade	Dorco ST301	New Platinum	Stainless	Vietnam	~2023
Shaves	0	P3	P6	P9	P12
Location	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top
Medium	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29
Dulling Substrate	New	Paper	Paper	Paper	Paper
Measurements	30	30	30	30	30
Std. Dev.	7	9	11	10	14
Median F (g)	66	64.5	67.5	74	77
Mean F (g) Btm	65	70	75	80	84
Mean F (g) Top	66	64	66	70	78
Mean F (g)	65	67	71	75	81
BESS Adj. Factor	0.83	0.83	0.83	0.83	0.83
Av. Adj. F (g) Bt	54	58	62	66	70
Av. Adj. F (g) Top	55	53	55	58	64
Median adj. F (g)	55	54	56	61	64
Mean adj. F (g)	54	56	59	62	67

The objective performance of this blade is very impressive. I wish I hadn't shaved this morning because I am eager to find out if the edge feels smooth and comfortable. It is unusual enough that I am wouldn't try to predict that based on the appearance of the blade. On the one hand, you have the coarse and uneven primary grind, on the other, you have very consistent sharpness along the edges and a resilient steel, and there is the question about whether the bevel has a flat grind or not. I guess I will probably find out tomorrow.

Incredibly, you can get a case of 1000 of these for $65.50 on Amazon, or, absurdly, a subscription of regular deliveries for $62.22 per case.

Blade Sharpness Test Index

Complete Data

 

[WhiskerLess]

The Dorco New Platinum STP-301 Stainless blade is made in Vietnam under license from the Korean company.

I should have waited for this test before placing my Dorco Prime order.

Sometimes it’s confusing the way they label their blades. In AMZN Dorco Primes are actually STP-301. But I saw your previous tuck showing STP300-10P which makes me wonder what are the difference or just simply version number.

 

[Jay21]

I haven’t met a Dorco that I haven’t liked (assuming made in Vietnam).

 

[Sweeney_]

I should have waited for this test before placing my Dorco Prime order.

Sometimes it’s confusing the way they label their blades. In AMZN Dorco Primes are actually STP-301. But I saw your previous tuck showing STP300-10P which makes me wonder what are the difference or just simply version number.

If I remember correctly, it's just packaging. STP-301 is plastic and STP300 is cardboard tuck.

The one he just tested in red/white is the ST-301. Stainless in plastic tuck.
Also available in cardboard tucks as
ST300

 

[helicopter]

The Dorco New Platinum STP-301 Stainless blade is made in Vietnam under license from the Korean company. It is a blade of exceptional sharpness, the fifth sharpest tested so far, and it is reasonably durable and consistent. It appears to be made of tough and resilient steel. I am sure everyone at Dorco would be proud of the fact that this blade is sharper than any Russian or Chinese blade I have tested so far.

Thankfully, I still have 99 of them left.

View attachment 1885543

It comes in plastic tucks of ten blades, which are individually wrapped in printed waxed paper with no dots. The only things missing are a date code and alloy. I don't know why anyone wouldn't share the alloy, as it is something that is very easy for their competitors to check anyway with an XRF metal analyzer.

View attachment 1885544

View attachment 1885545

The blade has nice printing.
View attachment 1885546

It has a coarse and uneven grind, with a honed edge, and a heavy distal coating.
View attachment 1885547

After testing, we see the edge is in excellent condition with some small dents and no chipping. I am surprised they got such a tough steel to stay so sharp through the test. This is excellent steel. The curved scratch lines on the primary bevel make me wonder if the edge is an S-grind or concave grind as well. Advanced edge geometry may partly explain this blade's exceptional performance overall.
View attachment 1885548

Information Summary:

View attachment 1885549

Date	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24
Blade	Dorco ST301	New Platinum	Stainless	Vietnam	~2023
Shaves	0	P3	P6	P9	P12
Location	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top
Medium	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29
Dulling Substrate	New	Paper	Paper	Paper	Paper
Measurements	30	30	30	30	30
Std. Dev.	7	9	11	10	14
Median F (g)	66	64.5	67.5	74	77
Mean F (g) Btm	65	70	75	80	84
Mean F (g) Top	66	64	66	70	78
Mean F (g)	65	67	71	75	81
BESS Adj. Factor	0.83	0.83	0.83	0.83	0.83
Av. Adj. F (g) Bt	54	58	62	66	70
Av. Adj. F (g) Top	55	53	55	58	64
Median adj. F (g)	55	54	56	61	64
Mean adj. F (g)	54	56	59	62	67

View attachment 1885550

The objective performance of this blade is very impressive. I wish I hadn't shaved this morning because I am eager to find out if the edge feels smooth and comfortable. It is unusual enough that I am wouldn't try to predict that based on the appearance of the blade. On the one hand, you have the coarse and uneven primary grind, on the other, you have very consistent sharpness along the edges and a resilient steel, and there is the question about whether the bevel has a flat grind or not. I guess I will probably find out tomorrow.

Incredibly, you can get a case of 1000 of these for $65.50 on Amazon, or, absurdly, a subscription of regular deliveries for $62.22 per case.

Blade Sharpness Test Index

Complete Data

I put STP301 in the first sentence here, but it is ST301 as pictured.

 

[helicopter]

The Dorco New Platinum ST-300 Stainless blade is made in Vietnam under license from the Korean company. It has a substantial variance in sharpness from one edge to the other, which is not something I like to see. It appears to be ground at a wide angle.

Unfortunately, I still have 99 of them left. At least it was inexpensive.

It comes in a cardboard box with ten cardboard tucks of ten blades each.

The individual blades are double wrapped with nice printing on both papers and no wax dots. There is a date code on the end of the tuck, unlike the one in a plastic tuck.

It has a thick bevel with a fine grind and some honing at the edge.

This ST300 is definitely different from the thinly and coarsely ground bevel and more proximal honing on the ST301 I tested immediately before this one. The STP300 Prime Platinum cardboard blade I tested previously is also a different grind from these two. The STP300 has a thin and fine primary grind, with the more proximal honing like the ST301. The STP300 was like the ST301 except with a finer and more consistent primary grind. I suppose it is possible it is just an old belt versus a new belt between the STP300 and ST301 blades I tested, but I would hope they are controlling their processes better than that.

After testing, there is a lot of fine chipping along the edge. It looks worse than it should considering how consistent it was in sharpness through the test.

Information Summary:

It looks moderate on the chart, but more detailed analysis in the table shows that one edge was fairly dull, and the other fairly sharp.

Date	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24
Blade	Dorco ST300	New Platinum	Stainless	Vietnam	April 14, 2019
Shaves	0	P3	P6	P9	P12
Location	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top
Medium	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29
Dulling Substrate	New	Paper	Paper	Paper	Paper
Measurements	30	30	30	30	30
Std. Dev.	14	13	9	12	12
Median F (g)	91.5	84.5	80	87.5	94.5
Mean F (g) Btm	104	94	88	97	104
Mean F (g) Top	80	79	75	81	86
Mean F (g)	92	87	82	89	95
BESS Adj. Factor	0.83	0.83	0.83	0.83	0.83
Av. Adj. F (g) Bt	87	78	73	81	86
Av. Adj. F (g) Top	66	66	62	67	72
Median adj. F (g)	76	70	66	73	78
Mean adj. F (g)	76	72	68	74	79

The durable coating is indeed such that both edges actually got sharper on the first cut test and again on the second cut test. If you are lucky enough to get a batch with two edges that are of a suitable sharpness, this would be a good blade to use for a long time. It take a lot of wear before it starts to degrade. Most people could easily take it a week before seeing any drop in cutting performance.

The variance we see here is disappointing. I consider this batch of blades to be of poor quality overall. As I have said of other blades with major issues, it isn't terrible, but it also isn't good. You will feel a difference between these two edges if you use a blade like this one. It is not something we should see.

Blade Sharpness Test Index

Complete Data

 

[cranewarrior]

I tested the PearlMax, which is a Chinese blade and brand. It is another moderately sharp blade of good durability and consistency.

It comes in a five blade tuck with holographic foil on it. The individual blade is single wrapped in nicely printed heavy paper with no wax dot. The printing on the blade looks typical.

View attachment 1885510


View attachment 1885511

It has a medium grind and a honed edge with moderate and reasonably even distal coating.
View attachment 1885512


The edge is barely changed with testing. THe coating is worn a bit, and the bevel is a bit smoother.

View attachment 1885513


It is moderately sharp with excellent consistency.

View attachment 1885519

Date	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24
Blade	PearlMax	Super Platinum	Super Stainless	China	~2023
Shaves	0	P3	P6	P9	P12
Location	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top
Medium	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29
Dulling Substrate	New	Paper	Paper	Paper	Paper
Measurements	24	24	24	20	20
Std. Dev.	9	7	9	8	8
Median F (g)	86	83.5	85	88.5	86.5
Mean F (g) Btm	91	86	89	92	91
Mean F (g) Top	80	82	80	83	84
Mean F (g)	86	84	84	87	88
BESS Adj. Factor	0.83	0.83	0.83	0.83	0.83
Av. Adj. F (g) Bt	76	71	73	76	76
Av. Adj. F (g) Top	67	68	66	69	70
Median adj. F (g)	71	69	71	73	72
Mean adj. F (g)	71	69	70	73	73

I have done abbreviated tests on these last two blades, with 112 cuts instead of the usual 150. This saves me a decent amount of time, so I am probably going to keep the change for most blades, and keep the 150 cuts for blades I consider to be especially important. Just in case there is some difference in blade wear from the measurement, I am going to switch media again soon. I had some concern when I saw how consistent these two blades were in the tests.

I prefer to wear the blades on the paper and minimize the impact of measurement on the edges, so I am going to test some thinner media this week. It's not a big concern, and I believe the tests with 0.29mm media are comparable to those done with BESS media, but I also think the that if I am not doing the same number of cuts on every edge, I should reduce this factor as much as practical, and I had excellent results with slightly smaller 0.27mm media in earlier testing.

I ordered 2 km of 6-lb test line, so wish me luck in getting good performance from it. I will need to pick a different point for defining a dead spot and capping force as well. I will probably base that on one standard deviation above the mean for the Flying Eagle Carbon Steel blade with some rounding to keep it simple down the line. I will need the media here to work that part out.

View attachment 1885521

Blade Sharpness Test Index

Complete Data

I recently used PearlMax though it was in different packaging. It felt fairly dull to me and your measurements make me want to try this version.

 

[helicopter]

Finally, for now, we have the new Dorco Prime Platinum in a plastic tuck. This one doesn't have a part number on it, but retailers who are breaking down the bigger boxes of these tucks are calling it the STP-301, so I will too. It doesn't have a date printed on it, but it was purchased within the last month.

This is the dullest of the four Dorcos tested so far, and like the ST-300, there is a large variance between the cutting force on one edge and the cutting force on the other edge. This one is the worst. You probably wouldn't want to use this batch.

This might be the same blade as the ST-300. It looks similar under a microscope, and the edge that is reasonably sharp on this one is just slightly duller than the edge that is reasonably sharp on the other one; so there is some overlap in the performance of the two, despite this one being worse overall, with one edge that is far too dull to meet any reasonable specification, despite being a flagship "Prime" blade.

This STP-301 has a finely ground uneven edge of medium thickness with distal honing and uneven medium coating. It looks similar to the ST-300. It might be the same blade.

After testing, we see some medium chipping along the edge; the steel is typical mid-grade.

Information Summary:

Date	7/29/24	7/29/24	7/29/24	7/29/24	7/29/24
Blade	Dorco STP301	Prime Platinum		Vietnam	~2023
Shaves	0	P3	P6	P9	P12
Location	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top	Bottom/Top
Medium	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29	Stren 8 .29
Dulling Substrate	New	Paper	Paper	Paper	Paper
Measurements	20	20	20	20	20
Std. Dev.	22	24	20	27	21
Median F (g)	97	98.5	104	98	112
Mean F (g) Btm	111	120	122	130	129
Mean F (g) Top	81	83	86	86	96
Mean F (g)	96	101	104	108	112
BESS Adj. Factor	0.83	0.83	0.83	0.83	0.83
Av. Adj. F (g) Bt	92	99	101	108	107
Av. Adj. F (g) Top	67	69	71	72	79
Median adj. F (g)	81	82	86	81	93
Mean adj. F (g)	80	84	86	90	93

It is a good thing I only have one tuck of this one.

Blade Sharpness Test Index

Complete Data

 

[Flanders]

Yeah, I bought 300 a few months ago. I know somebody else who just did the same this week. Roll those dice!
(or spend your money on Schicks and Accuforge blades)

Edit to add that from now on, I am trusting my own instinct and binning blades ruthlessly. If I end up throwing out hundreds then so be it!

 

[Sweeney_]

Yeah, I bought 300 a few months ago. I know somebody else who just did the same this week. Roll those dice!
(or spend your money on Schicks and Accuforge blades)

Edit to add that from now on, I am trusting my own instinct and binning blades ruthlessly. If I end up throwing out hundreds then so be it!

It's disappointing to see so much variation between the edges of the Dorcos and even between what should be the exact same model blade in different packaging. Hopefully I was lucky on my last purchase. That first STP-301 that was tested in the cardboard tuck came from a batch of 200 I ordered back in March and they seem to shave just fine.

 

[helicopter]

Perhaps this is why Amazon offers a subscription to 1000 blade cases. You can set it at 3 months or so, and you should get a new batch to try each time. Eventually you are bound to hit the jackpot and get a lifetime supply of good or even excellent blades.

It might be cheaper just to buy Accutec Personnas, but that isn't as thrilling.