knife not staying sharp

E

eprst

Joined
Feb 20, 2013
Messages
3
Hello
I've got a Spyderco Sage knife in maxamet steel. For some reason it is not staying sharp for long.
I'm sharpening it to 20 DPS using diamond stones and a jig to keep angles consistent. I can make it very sharp with mirror finish.
But it only stays very sharp for a day or two, then it stays decently sharp for a long time, but not sharp enough to shave, dice tomatoes or push cut paper.
I'm not abusing it, it is only used for light work. There's no visible chipping.
Any advice?
 
Super-sharp, highly polished edges do not last long at their peak sharpness. If you want a long-lasting working edge, stop at a lower grit and do not polish. I sharpen my Spyderco Maxamet with a 1000 grit diamond stone, and strop, if stropping is needed, on unpasted denim or leather. The edge lasts quite a while, even cutting abrasive cardboard.

Dicing tomatoes and cutting citrus fruits is less hard on the edge of high-chromium stainless steels, which are better able to resist the acids.
 
As has been mentioned, an edge that's less polished will usually be more durable in typical tasks. Try finishing at around 600 grit with the diamond hones and test sharpness by slicing paper (instead of push-cutting) and slicing a tomato. If the edge is fully apexed and burr-free* when finished, sharpness should remain much more stable.

* 19-FEB-2026 - Edited to add:
Sharpness which quickly diminishes with little use is often the result of incomplete burr removal. And on guided systems used to polish to a high degree, the burrs formed at the edge can become extremely thin and very unstable. Burr removal is usually best done by raising the held angle a bit and using very light strokes to bend the burr back toward the bevel away from the stone, so it can then be turned over into the stone and scrubbed away with light edge-leading passes. If the angle isn't raised to fold the burr, the burr will be much more difficult to clean up.
[End Edit]

Improved cutting performance comes mostly from narrower edge geometry. Very fine push-cutting of paper and other things can improve when the edge geometry is taken narrower than 20 dps. Big improvements can be seen at 15 dps or narrower. Most blade steels can remain stable in non-abusive tasks at edge geometry down to 12.5 dps (25 degrees inclusive), and the edge finish of choice will become somewhat less of a factor at narrower geometry. But until the edge geometry is taken narrower, the most straightforward strategy would be to finish at medium grit and don't polish too much beyond that.
 
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My most used shop knife is a Sypderco Maxamet at 15 DPS, which is also almost solely used to cut cardboard. I love polished edges and find it stays shaving sharp after cutting around 200-300 feet of cardboard. Not a comfortable shave but it will shave nicely, say around 200 BESS . I would question the integrity of the apex when you are done sharpening. Maxamet is a fun steel to sharpen, as I find it has similarities to ceramic. You have to be very careful not to damage the apex as it fractures easily, which is more noticeable the finer the stone you use.
 
Obsessed with Edges said:
As has been mentioned, an edge that's less polished will usually be more durable in typical tasks. Try finishing at around 600 grit with the diamond hones and test sharpness by slicing paper (instead of push-cutting) and slicing a tomato. If the edge is fully apexed and burr-free when finished, sharpness should remain much more stable.

Improved cutting performance comes mostly from narrower edge geometry. Very fine push-cutting of paper and other things can improve when the edge geometry is taken narrower than 20 dps. Big improvements can be seen at 15 dps or narrower. Most blade steels can remain stable in non-abusive tasks at edge geometry down to 12.5 dps (25 degrees inclusive), and the edge finish of choice will become somewhat less of a factor at narrower geometry. But until the edge geometry is taken narrower, the most straightforward strategy would be to finish at medium grit and don't polish too much beyond that.
Click to expand...
What he said...
I keep our kitchen knives around 100 Bess. And yes, that super sharp apex only lasts for two or three uses. After that initial sharpness wears off super steels begin to shine. They will maintain a sharp edge longer than standard steels.
You can test this yourself but what you are describing is pretty normal I believe. I don't know of any steel that would keep a 100 BESS score for more than a very few uses.
The suggestions will help but a 100 BESS reading leaves an unbelievably tiny apex. It is just too fragile for long term expectations. IMHO

Edit: The reason to sharpen super sharp...The sharper a knife is to start, the longer it stays sharp. Generally speaking.
 
I had a Schrade 340T that was made in the U.S. Managed to lose it.

The replacement 340T is made in China. I sharpen it, then I swear that it will get dull without even using it.
 
Thank you for your hints. I actually tried finishing at 700-800 grit and then stropping, didn't help much. Time to try 15 degrees and maybe a microbevel.
I also suspect I may be getting a micro-burr which gives this fragile super-sharpness, but I don't know how to check or remove it, I was hoping stropping should take care of it.

I sharpen it, then I swear that it will get dull without even using it.
Click to expand...

Mine is from Taiwan, but I get the same feeling
 
The user's technique is a factor that rarely comes up in these discussions.

An edge sharpened to a more acute angle (maybe starting around 15 degrees per side) is much more susceptible to poor cutting technique than one sharpened to a more robust angle. If you are sharpening to a lower angle you had better not be using the knife like a hatchet, chopping rather than slicing. A well-trained cook will enjoy that ultra sharp edge considerably longer than the guy who slams his apex into the board and then wonders why it dulls so quickly.

I took a cooking class once, and one of the instructors demonstrated how important this is. He put a big, over-ripe tomato on a single layer of paper towel, on a stainless steel surface. He sliced the tomato into a million ultra thin, translucent slices, and then he picked up the paper towel. He had not sliced the towel, the towel was completely intact. He was slicing the tomato, but his technique was such that he didn't cut the paper the tomato was resting on. Much different from the way most folks use their knives!

I think many of us, especially when we first get seriously involved in the sharpening process, pay way too much attention to shiny bevels and excessive stropping.
 
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