S35VN sharpening issues

S

Securis

Joined
Jan 9, 2013
Messages
69
I've had some trouble sharpening S35VN on several brands of blades.

the first one i did was a ZT450 which was actually the most frustrating. I used the Edge Pro for all my sharpening tasks, using aluminium oxide stones, going up the grits from 220, 400, 600, 1000, and finishing on 3000 grit polishing tapes. I found that the edge had literally no bite left. It was sharp and could cut newsprint (with some minor tearing), but you could run your finger on edge with some pressure and won't get cut.

I tried increasing the angle as i suspected i was tearing out chunks of carbide. along the way, i would try for bite and sharpness as i progressed on the grits and still found bite being reduced.

Went back to a lower angle and found that i was getting back at square one. I had another ZT450 new and untouched, and did, at the very least, find that i had slightly improved the cutting capability of of the 450 i was working on.

I eventually tried using an SF diamond plate (it's all i have right now) and found that bite was returning to the edge. I then jumped straight to the 3000 polishing tape and gave it a bit of a mirror. While it was improved, i'm still no where near happy with the performance.

I've also done a few Chris Reeve knives, The hawke ti lock, sebenza, inkosi, zaan. All these had similar results, but not quite as bad as the 450. I just find that it was loosing it's bite and wouldn't slice newsprint easy or cleanly. I used diamond plate and polishing tape on this one at first. I then tried again without the polishing tape and found that yes, it retained plenty of bite, but was just too course to be happy with the results.

More recently, i've sharpened a few Hinderers (an XM18 and an eclipse i think, i don't really follow hinderer's knives) Despite the much higher angle and thickness of the blade, i got them slicing pretty well. this time though, i went entirely on Aluminium oxide stones and finished all the way up to 3000 grits polishing tape.

I find it very frustrating to get so many different results from different brands. I know there are many factors that would cause me to have different results, other than the grits and finishes i employ. Pressure i put on the stone, bevel angle, heat treat, burnt edge from power grinding.

I know sharpness is relative, and someones hair popping sharp might be someone elses dull. I've been told many times to give it a rest, that it's good enough, but when i know it's possible to get it better (my elmax and D2 blades are satisfactory sharp for me, so i know what is achievable) i just cannot let it rest.

Any assistance and feedback is greatly appreciated.
 
Too many stones, do a 220, 600, 3000 for reprofiling, or 1000, 3000 to bring back the edge after it starts to dull or 400, 1000, 3000 if really dull.

Also make sure you are fully apexing on each stone

After your stones then strop,

also make sure you are deburring properly and don't make a huge burr. Also weaken the burr on the stones before moving to strop.

Keep in mind the polish reduces cutting endurance.

If you cut box's all day, need them teeth.

Also 15dps (no microbevel) is magic number for high performance on quality knives and experienced users.

Your angle sharpener doesn't guarantee a sharp edge there is still some thinking and troubleshooting involved. It just limits one of the biggest variables, angle inconsistency.

But doesn't do anything about burr formation, size, removal

Foil edges and burr keep ya from cutting, also not fully apexing (not sharpening to a burr) makes a "roundy" edge.
 
Aluminum oxide abrasives do not polish high vanadium carbide steels, like S35VN, in my experience. If you want somewhat polished edges, you would need diamond abrasives. I am currently testing 1 um diamond suspension deposited on the #2,000 polish tape of Edge Pro. So far, I can get an edge, which feels similar to VG-10 or LC200N sharpened up to #600 (of Edge Pro) and stropped on leather loaded with 3 um aluminum oxide. It has a good bite and yet push cut tissue paper without tear.


Miso
 
I've had similar issues with S35VN so I keep it Coarse.

I've polished a few S35VN blades up to my 1200 and 8000 mesh DMT plates and every time the steel just seems to lack bite and "run" over the surface of the things to be cut. Most of the time I stick with my Coarse DMT followed by some stropping with 1 micron diamond paste or if I'm using my Shapton Glass stones I will stop at 500 and finish with a little stropping. This edge type seems to allow much better practical sharpness and edge retention.

As other have said though, the aluminum oxide abrasive you are using will be holding you back. Once you start getting into the 15-20 micron abrasive size range your stones will drastically slow down from the interaction with the VC carbides.
 
Some of the advice given thus far, is good. If you are unable to get a consistently sharp edge, you are not fully establishing and removing a bure from each side. It's not some "mystical ability" to establish hair popping edges. If you create a bure on each side & hone it down to 0 edge with a 25 degree or less angle, you are going to have an extremely sharp knife. It has no choice but to obey the laws. I would also rec. ditching the aluma oxide and polish tape.(they suck) Get a set of ceramic water stones or diamond plates(stones). I use the Shapton Glass stones. Then practice what has been recommended here.
 
Yes , S30V and S35VN I prefer a micro-serrated edge for all purpose EDC work.
 
Thanks for the response guys, i'm glad to be getting some support.

I've tried several combinations of stone progression. The one i eventually went with was diamond straight to polishing tapes.

I do ensure i achieve the apex on each stone by achieving a burr (a very slight one), even on the polishing tapes. I've actually ordered some diamond plates, a couple shapton glass stones, and a naniwa water stone for the edge pro from CKTG. I've also got some DMT and richmond diamond stropping compound incoming.

2 methods i use to check for burr is to first feel for it with my fingers, and then i use a flashlight above the edge to check for reflection. I always ensure that no light gets reflected. Are there other methods to check for it?

I've been contemplating trying free hand for awhile, is there any significant advantage over the egde pro? Or should i just stick to what i'm familiar with.

I was watching a video by Michael Christy and realized he uses different stones for different types of steels (or carbide formers to be exact).

One thing i'd like to learn is to find out is to know which element (Cr/V) carbon decides to absorb.
 
Free hand sharpening is a fantastic skill to possess. But it, alone, is not going to miraculously make your knives sharper. I used the Edge Pro for many years, but now I use my my own built system similar to the Edge Pro. It uses the Edge Pro, or Hapstone stones. My edges are insanely sharp using an Edge Pro style sharpenering system. But I have invested a considerable amount of time in perfecting my technique. You should deffinately give free hand a try, as some people just have a knack for it. So, it is possible that certain people will be better with one over the other. But it's a condition relative to the individual. It has nothing to do with one system or the other. You could make a crude system with some 2x4 and a rod or thin, fairly stiff wood bar. Tape the stones to the rod and raise the back of it against some wood. Position the knife off the end of the 2x4 with the Edge facing you. Use a sharpie to locate the angle and go to town. It's very simple- use high quality sharpening stones, maintain a consistent angle on the blade and the knife will be just as sharp as a $700 sharpening system.
 
Securis said:
Thanks for the response guys, i'm glad to be getting some support.

I've tried several combinations of stone progression. The one i eventually went with was diamond straight to polishing tapes.

I do ensure i achieve the apex on each stone by achieving a burr (a very slight one), even on the polishing tapes. I've actually ordered some diamond plates, a couple shapton glass stones, and a naniwa water stone for the edge pro from CKTG. I've also got some DMT and richmond diamond stropping compound incoming.

2 methods i use to check for burr is to first feel for it with my fingers, and then i use a flashlight above the edge to check for reflection. I always ensure that no light gets reflected. Are there other methods to check for it?

I've been contemplating trying free hand for awhile, is there any significant advantage over the egde pro? Or should i just stick to what i'm familiar with.

I was watching a video by Michael Christy and realized he uses different stones for different types of steels (or carbide formers to be exact).

One thing i'd like to learn is to find out is to know which element (Cr/V) carbon decides to absorb.
Click to expand...



Remember that the #3,000 polish tape seems to use aluminum oxide as abrasive (Reference). You would want to use a diamond lapping film or silicone carbide sand paper at least.


Miso
 
miso2 said:
Remember that the #3,000 polish tape seems to use aluminum oxide as abrasive (Reference). You would want to use a diamond lapping film or silicone carbide sand paper at least.


Miso
Click to expand...

would finishing with a diamond paste strop alleviate that issue? As in either i go through the normal steps, polish on the 3000 tape, and strop with diamond compound, or i skip all tapes (ouch! cause i just ordered 6000 grit EP tapes, which is fine, they don't cost too much) and go straight to strop. I did also get 6K shapton glass stones, that might do it for me for polishes.

How would you say Ceramic stones behave on vanadium/chromium steels? I know why diamond is preferable on V steel, that it cuts the harder carbides.
 
The Shapton Glass will take care of pretty much any steel you. Especially the higher grit, as they do not remove material. The 6K Shapton Glass is a fantastic finishing stone! I use it on many knives and skip the strop. I like using bonded diamond to reprofile and metal removal of the real high alloys and high speed steels. Saves time, and more importantly, doesn't waste my expensive stones. But I like switching to the 500grit Shapton Glass, followed by 1000gr, 4000gr, 6000gr and sometimes 8000gr.
 
Securis said:
would finishing with a diamond paste strop alleviate that issue? As in either i go through the normal steps, polish on the 3000 tape, and strop with diamond compound, or i skip all tapes (ouch! cause i just ordered 6000 grit EP tapes, which is fine, they don't cost too much) and go straight to strop. I did also get 6K shapton glass stones, that might do it for me for polishes.

How would you say Ceramic stones behave on vanadium/chromium steels? I know why diamond is preferable on V steel, that it cuts the harder carbides.
Click to expand...


I think finishing with diamond abrasives is ideal. In my limited experience, even the silicone carbide #2,000 polish tape does not give a finish, which feels like polished at that girt, on S35VN. So I say to go with diamonds.

With that said, I don’t think ceramic stones, made of mostly aluminum oxide, silicone carbide, and tungsten carbide, work well on S35VN, since vanadium carbide might be harder than any of them. My only experience is with aluminum oxide ceramic, and I was not happy with the result.


Miso
 
@miso2

Are Shapton glass stones Al oxide as well? if yes, then d#%^it! i got a couple on the way.

@nomo4me
Does it cut metal (steel matrix) or carbides aggressively? I hope it's the latter.
 
I do not have them and cannot comment myself. I looked up their web site, and it says their glass stones can sharpen anything other than ceramic or tungsten carbide.


Miso
 
Ooh it will cut just fine, its not a one to one translation of what the abrasive hardness is and what the carbide in the steel is, its wayyy more complex. Its to be used as a reference not the end all be all.

So many factors, also alumina is almost as versatile as steel since it can be "alloyed" or fused with other abrasives to change its proprieties and can have a variety of different bonds and still be cooperative when being made into a stone.



I've sharpened my CRK Large Inkosi at 59-60HRC just fine with the Shapton glass, 500 and 2000.
 
I have used the Shaptons on many different steels, including super steels. knives I make are almost exclusively from CPM3V and CPM20CV(which has the same amount of Vanadium, A LOT more Chromium and a pinch of Tungsten). The Shaptons have no problem doing the job, and leave an edge with incredible bite.
 
@BeadboxHero & @DavidHoback
Thanks for the clarification. I'll be eagerly awaiting my stones to arrive (that sounded different in my head).

As of now, I usually run through a series of different finishes with different types of stones to experiment on what works best for a steel i'm not yet familiar with. If there is a "rule of thumb" i can follow, based on the steel composition, and fine tune the process afterwards, that would greatly save me some time, stone and steel.
 
You must log in or register to reply here.
Back
Top