for cliff: trouble sharpening 154cm...grrrr

[MikeMade™]

Hey cliff, I went to sharpen my bm 520 and I cut into my medium spyderco ceramic to remove the weakened metal and cut down on burr formation. Well to my surprise the burr was extremely large once both sides were ground completely. I cut into the stone a couple more times to try and break off the burr and it kept coming back. So then I increased the angle to set a microbevel and the microbevel burred! What am I doing wrong?

 

[Cliff Stamp]

154CM is a difficult steel to sharpen because it is a high carbide steel with an extremely irregular and large carbide structure. It has a low grindability but at the same time is often fairly soft and deforms easily. It can thus be a nightmare to get a crisp edge to form and then it doesn't hold it well anyway.

The best thing you can do is get it rehardened. However if that isn't an option then you have to work with very clean and aggressive stones, so resurface oil/water stones and clean the diamond/ceramics. Cut into the edge to remove any burr and then alternate the sides on each pass and basically sneak back up on the edge and try to get it to form without oversharpening and producing a burr.

At times it is useful to use a trick I was taught by an engineer which never fails. Take an older piece of equipment which you have basically retired and violently destroy it in front of the equipment you depend upon but which is being tempermental. This both appeases the god of experimentalism and as well shows the current equipment its fate if it keeps acting up.

-Cliff

 

[MikeMade™]

Hahahaha, thanks Cliff. Yeah I don't have any heat treating equipment so I'll have to try alternating each pass once i figure out which extra course stone I wanna buy.

 

[EDCeeker]

154CM is a difficult steel to sharpen ...

Really? And here I was thinkin' 154CM was one of the (relatively) easier steels on which to get a good edge. (Like ATS-34.)

It can thus be a nightmare to get a crisp edge to form and then it doesn't hold it well anyway.

This comes as a shock to me, as well.

When I originally set out to get my first "good" folder, some six months ago, I first spent plenty of time reading what people had to say about the various knife manufacturers, designs (incl. lock types, handle materials, and blade profiles) and blade steels. From this, I gathered that 154CM/ATS-34 (they're nearly identical, no?) and VG-10 were steels that held an edge relatively well, weren't much prone to shattering/fracturing/chipping, and were relatively easy to get a good edge on. This is why those three steels became my first choices.

Now it seems you're saying I went wrong somewhere?

 

[Andros]

Really? And here I was thinkin' 154CM was one of the (relatively) easier steels on which to get a good edge. (Like ATS-34.)

This comes as a shock to me, as well.

When I originally set out to get my first "good" folder, some six months ago, I first spent plenty of time reading what people had to say about the various knife manufacturers, designs (incl. lock types, handle materials, and blade profiles) and blade steels. From this, I gathered that 154CM/ATS-34 (they're nearly identical, no?) and VG-10 were steels that held an edge relatively well, weren't much prone to shattering/fracturing/chipping, and were relatively easy to get a good edge on. This is why those three steels became my first choices.

Now it seems you're saying I went wrong somewhere?

I don't mean to be rude but according to my own experience ATS-34 (and for that matter 154CM since they are basically the same) is one steel that every time I see a knife made of it this alone is a criterion for me not to buy it. Now, VG-10 differs a lot and has given me much more positive responsiveness. That is why I am positive towards VG-10.

 

[Cliff Stamp]

And here I was thinkin' 154CM was one of the (relatively) easier steels on which to get a good edge. (Like ATS-34.)

154CM and ATS-34 are different manufacturers versions of the same steel. They are very high carbide steels with a lot of large chromium carbides, about 25 microns. They thus work best with fairly coarse edges. The main problem is that most are leaving the edges too thick and running the steel too soft. If you really want to see how the steel can perform then have some like Wilson reharden and regrind the blade. You can expect a performance increase which is many to one in several respects.

Now, VG-10 differs a lot and has given me much more positive responsiveness.

VG-10 is a pretty different steel because it removes most of the molybdenum which is in 154CM for secondary hardening which gives it a high hot hardness which is why it is used in things like turbines. However for knife blades using secondary hardness is a bad idea because you lose corrosion resistance, impact toughness and edge stability. VG-10 replaces the molybdenum with cobalt which acts to strengthen the steel and thus increase retention of the carbides. There are a huge family of such steels which are cutlery focused grades, unfortunately they are not commonly used in knives in north america.

-Cliff

 

[FK]

"154CM is a difficult steel to sharpen because it is a high carbide steel with an extremely irregular and large carbide structure. It has a low grindability but at the same time is often fairly soft and deforms easily. It can thus be a nightmare to get a crisp edge to form and then it doesn't hold it well anyway."

????????????

http://www.warrenknives.com/blade steels.htm

Warren indicates nothing negative for ATS-34,,,,,,could it be the poor heat treatment schedule with some factory knives.

Regards,
FK

 

[HoB]

could it be the poor heat treatment schedule with some factory knives.
FK

Of course, just because everybody focusses on S30V right now doesn't mean that ATS-34 is treated right all the time. But independent of the heattreat (well not completely independent) ATS-34 is, as Cliff just said, a coarse grained steel.

 

[rusty edge]

I've had great luck with my 154CM Benchmade Styker; it holds a nice edge. I think this is a unbiased opinion because I own S30V, VG10, H1, ATS-55, AUS and ZDP-189 to compare it too. My favorite is by far ZDP-189, it just sharpens soo easily and holds a beautiful edge. I like S30V's edge retention but it is a pain to sharpen for me. I really don't find, in my personal USE, and experience, a huge performance difference between VG10 and 154CM. I'm sure its true that VG10 holds an edge longer in the long run, but they all get touched up on the sharpmaker or strop after weekly carry regardless. So they all hold an edge long enough for me. I want to say again that ZDP-189 sharpens soo nicely, it really does live up to the hype. just love that steel.

 

[Cliff Stamp]

...could it be the poor heat treatment schedule with some factory knives.

The large carbide structure of ATS-34 is inherent in the steel due to the very high carbon and chromium content. Such high wear steels are simply not designed to hold fine cutting edges they are not knife steels. Ironically neither is S30V which is promoted on that page as being the first specific purpose knife steel. Steels like 13C26 are knife specific steels as of course are the many tool steels which are intended to hold fine cutting edges.

Most of the issues with 154CM which make it much worse than its actual potential have to do with the heat treatment and more so with the geometry and which knives it gets used to make. It is often in large tacticals and since the steel is inherently very brittle the edges are often thick and obtuse. This leave the knife with low cutting ability and it is then very difficult to sharpen because there is so much material to remove and on top of that you still have micro-cracking at the edge which is how it will dull in use. On top of this you have issues with deformation as makers will underharden it intentionally to try to make it tougher and this is generally a really bad thing for a whole host of reasons.

-Cliff

 

[roshi]

I own a number of Emerson knives which are all 154 CM. I've never had any trouble getting a good edge. Perhaps they have been using 154 CM so long that they have the heat treat right.

 

[UffDa]

I have owned a few knives made of 154CM that had the same problem. When trying to sharpen them, they felt "Gummy" on the stone and the edge would just fold over from one side to the other. I suspected it was a heat treat problem, because I had another 154CM blade that did not have the problem.

Who knows what evil lurks?

 

[Maqua]

My Benchmade 710 takes and holds a good edge, but nothing like an old Old Timer I have. The 154CM plate I sawed on for so long used up about 15 bi-metal hacksaw blades. It truly was an exercise to cut out the knife blank. I hope TKS knows how to heat treat this stuff.

 

[db]

ATS 34 154 cm is good knife steel if heat treated right depending on what type of edge you like and use.

 

[Cliff Stamp]

I own a number of Emerson knives which are all 154 CM. I've never had any trouble getting a good edge.

Note that when it is mentioned that steels have limitations in regards to ability to obtain a high sharpness this is only in reference to high push cutting sharpness and specifically a very high level, above shaving sharpness for example, approaching the sharpness of an actual razor blade.

When trying to sharpen them, they felt "Gummy" on the stone and the edge would just fold over from one side to the other.

The most common hardening problem is underhardening because pretty much everything not done optimally reduces the hardness of a steel. As the hardness drops on a high wear steel you get the exact performance you describe. This can be fixed by rehardening however the procedure can be complicated especially if the steel was tempered so as to induce secondary hardening which is common in 154CM.

-Cliff

 

[STR]

The 154CM and ATS34 steels are the only two I most always own in combo edge only just for this reason. The way I figure it they at least cut that way when I need them to but truthfully this steel is the one I have noticed to burr the most also. I say this steel but refer to both.

I've found that some of the blades of this are great and don't burr that bad if at all. Those I keep. Others are the biggest PITA that you can imagine and I usually donate those to someone that needs a knife or for some other cause.

I hate the bad ones. I've had great luck with Emerson 154CM, and Buck (BOS) ATS34 though. These have been some admirable performers.

STR

 

[thombrogan]

Steels like 13C26 are knife specific steels as of course are the many tool steels which are intended to hold fine cutting edges.

You'll never win the public over with a medium carbon stainless. Look to see what 19C27 can do for you.

ATS 34 154 cm is good knife steel if heat treated right depending on what type of edge you like and use.

If you want an edge thicker than 20-22 degrees per side, I agree. The back bevel or plunge or hollow or whatever you call it behind that edge/microbevel can be fairly thin if you limit your cutting to soft-yet-abrasive/corrosive materials. My experience/thinking with 154CM/ATS-34 and S30V is that if you have a stable edge at 15 degrees per side, it's too thick.

 

[sjahn]

You may try to use coarser stone if the knife keep developing burr that does not go away.
I had similar problem with VG10 and D2 blades sharpening on fine stone. Those burrs are bitch to remove.
I moved to slightly corser stone and the problem solved.
You can of course do what Cliff suggested (alternating each pass), though it is tedious to do.

Good luck with sharpening.

(BTW I haven't had problem with my one 154CM blade, though I generally sharpen it with corser stone than I used for VG10. Maybe that was the trick. I also heard from one who're more experienced in sharpening than me that 154CM often has rubbery feel and not always sharpen cleanly, so more care is needed.)

 

[Andros]

154CM and ATS-34 are different manufacturers versions of the same steel. They are very high carbide steels with a lot of large chromium carbides, about 25 microns. They thus work best with fairly coarse edges.

I had noticed exactly that with regards to the type of edge (i.e. coarse)! I just could not attribute it to any specific reason(s).

VG-10 is a pretty different steel because it removes most of the molybdenum which is in 154CM for secondary hardening which gives it a high hot hardness which is why it is used in things like turbines. However for knife blades using secondary hardness is a bad idea because you lose corrosion resistance, impact toughness and edge stability. VG-10 replaces the molybdenum with cobalt which acts to strengthen the steel and thus increase retention of the carbides. There are a huge family of such steels which are cutlery focused grades, unfortunately they are not commonly used in knives in north america.

-Cliff

So, my observation is not just a subjective thing but can be substantiated with scientific data. Thank you for explaining / elaborating on this.

 

[Cliff Stamp]

You'll never win the public over with a medium carbon stainless.

They are actually all high carbon by defination, the requirement is a lot lower than what most people think. But I don't need to be concerned about public opinion (shocker!) as I am not selling anything. Besides, eventually some knifemaker will get very vocal about such steels and they will be accepted as the the new ultimate steel anyway. You just need a P/M version with a cool name like P/M EPYH. I am waiting for people to realize that you don't need massive amounts of chromium in steel to enable it to cut something and watch Alvin's head explode with "I told you so!" 50 million times.

If you want an edge thicker than 20-22 degrees per side, I agree.

That's not a fair answer because you changed the question, that isn't a knife.

You may try to use coarser stone if the knife keep developing burr that does not go away.

Yeah, it often is the better choice for a lot of cutting anyway,

You can of course do what Cliff suggested (alternating each pass), though it is tedious to do.

Optimally you sharpen one side right up to the point the edge forms and then switch and repeat. The tricky part is knowing when to switch without viewing the edge under high mag (1000X). This is why you have to oversharpen (form a burr) or just alternate and sneak up on the edge. If you sharpen completely, then cut it off lightly (1-2 passes into the stone directly), it usually only takes a minimal of passes to reset the micro-bevel which means you are only alternating for a dozen passes or so. The basic procedure is hone on one side to burr, repeat on other side, cut off burr directly, alternate to sharp.

So, my observation is not just a subjective thing but can be substantiated with scientific data.

Yes, most people are fairly objective about such matters, aside from when they are emotionally attached to the product in some way. So don't ask the best friend of a knifemaker to comment on his blades or ask him and the knifemaker's ex-wife and the reality is likely between those extremes.

-Cliff