Blade Sharpness Research Project
- Thread starter helicopter
- Start date
- Thread starter
- #1,242
This is Sotraco's Lord Super Stainless patriot blade in a 5 blade tuck. It is a standard thickness blade, mild in sharpness, with good balance, and fair durability and consistency. Performance suggests a platinum driven metallic coating despite nomenclature that would conventionally indicate an absence of metallic coating.
It is a three stage grind with some large stria from using crude abrasives. The coating is sloppy. In the second photo, taken after the test, we see that the failure mode of the steel is lots of large chipping and some denting typical of Sotraco and inexpensive low-quality blade steel in general.
Performance doesn't closely align with other Sotraco blades tested so far. My guess is that this example, with its good balance, is close to the nominal specification, which seems to take some luck with Sotraco. The street price of this blade is around $8/100. At that price, the performance is completely uncompetitive. You can get vastly superior Chinese blades for half of the price.
Blade Sharpness Test Index
It is a three stage grind with some large stria from using crude abrasives. The coating is sloppy. In the second photo, taken after the test, we see that the failure mode of the steel is lots of large chipping and some denting typical of Sotraco and inexpensive low-quality blade steel in general.
Performance doesn't closely align with other Sotraco blades tested so far. My guess is that this example, with its good balance, is close to the nominal specification, which seems to take some luck with Sotraco. The street price of this blade is around $8/100. At that price, the performance is completely uncompetitive. You can get vastly superior Chinese blades for half of the price.
| Date | 5-Jan-2025 | Blade Thickness, mm | 0.100 | ||
| Blade | Sotraco | Lord | Super Stainless P5 | Egypt | 13-Nov-2021 |
| 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. | 16 | 8 | 26 | 26 | 25 |
| Median F (g) | 56 | 51 | 56.5 | 58 | 74 |
| Mean F (g) Top | 54 | 51 | 68 | 70 | 79 |
| Mean F (g) Bottom | 62 | 52 | 58 | 58 | 72 |
| Mean F (g) | 58 | 52 | 63 | 64 | 76 |
| BESS Adj. Factor | 1.39 | 1.39 | 1.39 | 1.39 | 1.39 |
| Avg. Adj. F (g) Top | 75 | 71 | 94 | 97 | 110 |
| Avg. Adj. F (g) Bottom | 86 | 73 | 81 | 80 | 100 |
| Median Adj. F (g) | 78 | 70 | 79 | 81 | 103 |
| Mean Adj. F (g) | 81 | 72 | 87 | 89 | 105 |
Blade Sharpness Test Index
Those seem all viable. In my quest to find good blades, I am just trying to figure out how I can use the information that you are gathering for a possible benefit for me. Perhaps it could also benefit others.
You mentioned that the Treets have a "clean grind categorization" and a "thicker and tougher edge" - What does that exactly mean, how are you determining those things? Is there a way to find blades with similar "grind" characteristics and similar "edge profiles"? Even if its just a subjective characterization, it may be helpful?
Maybe I missed it but would you be willing to make some of the data people would use to sort blades available in a read-only google sheet so we can sort in some way. For those that only use a blade once, it would be also interesting to see what the ranking would be of sharpness as new. If the blade doesn't get past the first shave, I'm not keeping it for the second or third.
No worries either way as I am sure is a lot of work.
Some more anecdotal info. I also have in my notes that Astra Blues and Wizamets felt tuggy to me as well but they rank well on the scale and sharper than Treet Classics.
Interestingly also, is that a lot of people claim Feather AC blades are the sharpest blades (or some of the sharpest) out there but none of them passed a hanging hair test for me. They also felt dull to me every time I have used them. They rank dull on your ranking despite convectional "wisdom" - which is great to see. So some of my experiences mirror your testing.
Who would have thought edge sharpness could be so complex?
Interestingly also, is that a lot of people claim Feather AC blades are the sharpest blades (or some of the sharpest) out there but none of them passed a hanging hair test for me. They also felt dull to me every time I have used them. They rank dull on your ranking despite convectional "wisdom" - which is great to see. So some of my experiences mirror your testing.
Who would have thought edge sharpness could be so complex?
- Thread starter
- #1,245
The cutting force wear curves of Treet blades tested fall into clean buckets making a stair-step chart, because their processes are well controlled. It follows that a typical Treet blade will perform close to the nominal specification, and it makes it easy to identify which grind specification they used for the model.
They don't have any grinds that are very sharp, because all of their specifications are for bigger angles at the apex.
Since grinds are done in stages at different angles, and my scalable images all show the side of a flat blade, I can't calculate the angles, but I can get a general idea by looking at thicknesses and bevel heights.
Voskhod is definitely more acute at the apex than any of the Treet blades, which should translate to more bending and flexing, and less plowing straight through.
Such publicly available Google Sheets do exist, but it is against forum rules to put the links here or mention the place where the links are published.
There is a zip file with an excel sheet higher up the thread that @BigAlVista updates and posts.
If you want to find blades similar to the ones you like, one strategy is to expand the big chart at the end of the most recent test, look at the blade you liked, and see if there are blades nearby with similar curve shapes. You could look up the tests in the index link there, and see if the test indicates a blade you might want to try.
Last edited:
- Thread starter
- #1,246
You could look at standard deviation in the test summary chart. That shows how much the sharpness varies from location to the next. If it varies a lot, then there will be some spots that are below the average sharpness. Those duller spots will certainly tug first, especially if they represent big chips or dents.
Eventually I plan to quantity smoothness using something like this, though it will be more sophisticated than just standard deviation. AI, which is very good at solving problems like putting a number on smoothness or tugginess, tells me I will probably want to use different formulas for each stage of the test, and that seems like a good way to do it.
I think there is probably a better way to express the centrality of the sharpness than averages, too, but averages are good enough for now, while I am focused on testing, and averages are easy to understand.
I still have more blades to test before I get into that, though. The plan is to test more, then clean up data table into something AI can manipulate very effectively, and then come up with some more analysis techniques. A lot of what is not reflected in the charts of averages has still been measured and is there in the data.
To the content in bold - This is becoming more interesting. In my shave notes, I use a word like "pop" where the sensation is the blade just plowing straight through as you say and popping off hair effortlessly. It's the same sensation I get when I use a heavy grind straight razor which has considerably less flex than something hollow ground. It's the best feeling and something I have been chasing. I always thought it had to do with sharpness for DE blades because they are all so thin compared to the body/edge of a straight razor. But maybe these small nuances in bevel angle, even in a really thin and flexy DE blade can give you that clean cutting "pop" feeling.
I will have to look at your pictures to see what I can discern. Like you said, the pictures are of a flat blade so I am not exactly sure what I am looking for but I'll try to give it a go this week. Thanks again for the other info as well.
I also haven't felt them to be that sharp. To me the sharpest AC blades are the Schick Prolines.
At least that's how they feel anyways!
I used a different Diplomat last week. I suspect these were made in the Personna plant in Israel, but I don't have any proof of that beyond the wrappers being the same as other blades I have from that plant.
Last edited:
- Thread starter
- #1,250
That's the one I just tested. It is definitely a Nazareth blade. Not just the wrapper. It has the Star of David on it. Is the tuck like mine, or is it the one that says the packaging is made in England?
I'll try to double-check the tuck tonight, and report back.
The first two shaves on it were nothing to write home about. Shave number three was a nice shave.
- Thread starter
- #1,252
This is Sotraco's Lord Platinum primary from a 5 blade tuck. It is moderate in sharpness with fair balance, durability and consistency. I believe this example is a reasonably good representation of the specification.
The scratches are not coarse, but they are uneven. There is a visible metallic coating. In the second picture we see that the failure mode of the steel was some medium chipping.
Performance is pretty close to the other Lord Platinum that is not labeled as "new" on the tuck, so I think they are probably both made to the same specification and both good examples of that specification.
Blade Sharpness Test Index
The scratches are not coarse, but they are uneven. There is a visible metallic coating. In the second picture we see that the failure mode of the steel was some medium chipping.
Performance is pretty close to the other Lord Platinum that is not labeled as "new" on the tuck, so I think they are probably both made to the same specification and both good examples of that specification.
| Date | 6-Jan-2025 | Blade Thickness, mm | 0.090 | ||
| Blade | Sotraco | Lord | Platinum Primary 5 | Egypt | 1-Mar-2021 |
| 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. | 13 | 11 | 16 | 30 | 23 |
| Median F (g) | 48 | 47 | 48.5 | 55.5 | 57 |
| Mean F (g) Top | 44 | 54 | 50 | 59 | 59 |
| Mean F (g) Bottom | 55 | 45 | 52 | 74 | 66 |
| Mean F (g) | 49 | 50 | 51 | 67 | 62 |
| BESS Adj. Factor | 1.39 | 1.39 | 1.39 | 1.39 | 1.39 |
| Avg. Adj. F (g) Top | 61 | 75 | 69 | 82 | 82 |
| Avg. Adj. F (g) Bottom | 76 | 63 | 72 | 103 | 91 |
| Median Adj. F (g) | 67 | 65 | 67 | 77 | 79 |
| Mean Adj. F (g) | 69 | 69 | 71 | 93 | 87 |
Blade Sharpness Test Index
- Thread starter
- #1,253
This is Sotraco's Lord Platinum in a red tuck of six blades packaged for the Malay Archipelago markets, and I believe it is made to the same specification as the primary color tuck version measured in the previous test.
The grind looks the same as the other one, but this one held up better to testing, with a failure mode of small chipping and denting.
I couldn't get a 90 micron measurement on this individual, but I suspect it is made from 90 micron stock like the other one, but warped.
This blade is included in the charts for the prior test above, so I won't post them again here.
Blade Sharpness Test Index
The grind looks the same as the other one, but this one held up better to testing, with a failure mode of small chipping and denting.
I couldn't get a 90 micron measurement on this individual, but I suspect it is made from 90 micron stock like the other one, but warped.
| Date | 6-Jan-2025 | Blade Thickness, mm | 0.093 | ||
| Blade | Sotraco | Lord | Platinum Red 6 | Egypt | 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 | 9 | 8 | 24 | 17 |
| Median F (g) | 54.5 | 49 | 50 | 48.5 | 51 |
| Mean F (g) Top | 51 | 49 | 54 | 62 | 60 |
| Mean F (g) Bottom | 56 | 50 | 49 | 41 | 48 |
| Mean F (g) | 54 | 50 | 51 | 51 | 54 |
| BESS Adj. Factor | 1.39 | 1.39 | 1.39 | 1.39 | 1.39 |
| Avg. Adj. F (g) Top | 71 | 69 | 75 | 86 | 84 |
| Avg. Adj. F (g) Bottom | 78 | 70 | 67 | 57 | 67 |
| Median Adj. F (g) | 76 | 67 | 70 | 67 | 71 |
| Mean Adj. F (g) | 75 | 69 | 71 | 71 | 76 |
This blade is included in the charts for the prior test above, so I won't post them again here.
Blade Sharpness Test Index
Similar threads
