Factory sharpening?

dkb45

dkb45

Joined
Dec 16, 2012
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I just got a knife back from Benchmade and the edge is pretty damn sharp, but I recently learned about carbide structure and how they work with sharpening and I was wondering how edges are done at the factory.

I know steels like M390 (the Barrage I got back) are best done with diamonds, CBN, or a few other natural or synthetic abrasives, and I was wondering if factories treated these steels properly or if they sharpened them with aluminum oxide or silicone carbide.

I did some research and found nothing definitive, just speculation.
 
Norton ceramic belts cut all steels pretty quick and they are commonly used. Efficiency of grinding is a very important factor in industrial settings because when running large volume of material using the wrong belts can ruin the work piece and cost time and LOTS of money.
 
I figured they would use ceramic belts. I knew it was unlikely they would do special treatment for vanadium carbide steel production models. Looks like I will need to break out my DMT Magna-guide.
 
If it's sharp enough that you enjoy it use it as it is unless your OCD is getting to you in which case go right ahead with the DMT.
 
Like I have always said, do not put the factory edge on a pedestal.
 
There's also a distinction to be made about 'ceramic' belts. The word 'ceramic only implies a process by which the abrasive is made, and not specifically the material of which it's made. 'Ceramics' can include base materials of alumina (most common), silicon carbide, zirconia and perhaps even CBN as well.

The makers of high-wear steels, containing vanadium carbides in particular, will usually include recommended grinding methods or materials in the data sheets for the steel. This is where you'll usually find what's best for industrial grinding of the steels in the manufacturing environment.

Another thing to think about: most factory edges are ground at pretty low grit levels (maybe 220 or lower), which won't really do much (or any) refining of the relatively small carbides in the steel. This is why many will still use AlOx ceramic belts for applying factory edges, in spite of the fact that it would take CBN or diamond to really refine those carbides, if the edge finish were taken further. At the coarse grit of most factory edges, the abrasives are just plowing the matrix steel away, stripping out whole carbides along the edge, as opposed to finely shaping them; much like a backhoe will dig large rocks out of the ground, in spite of the fact that it's blade isn't actually hard enough to grind the rocks themselves.

Most blade manufacturers will just use whatever's most economical to put acceptable factory edges on blades. It comes down to much $$ they spend on replacing belts or grinding wheels, in relation to how many blades they can get out the door for the $$ spent. AlOx-based belts & wheels (ceramic or otherwise) will always be cheaper up front, and likely what will be used most of the time.


David
 
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According to my coworker, who formerly worked in the sharpening departments at a well known Portland area knife company, it's very likely they use a bench grinder and a buffing wheel. His company freehand ground 2 passes on each side of the blade with the bench grinder and then ran it over a buffing wheel. Another large well known company in the area does pretty much the same, but uses a fixture to hold the knife.
 
I wouldn't worry much about factory sharpening unless I had a Rockstead. No regular production company is going to give you an edge as good as you can give yourself.
 
bpeezer said:
I wouldn't worry much about factory sharpening unless I had a Rockstead. No regular production company is going to give you an edge as good as you can give yourself.
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That was the first indicator that I was getting better at sharpening was that factory edges just weren't cutting it anymore. No pun intended.
 
Well I am a little disappointed, but I was expecting disappointment. I ask because I can't find my damn sharpener, and this is the best factory edge I have seen from Benchmade, all even and sharp. Looks like I need to find my sharpener.
 
dkb45 said:
Well I am a little disappointed, but I was expecting disappointment. I ask because I can't find my damn sharpener, and this is the best factory edge I have seen from Benchmade, all even and sharp. Looks like I need to find my sharpener.
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Well, here's a little story. One of the first "fancy knives" I've bought is a Tidioute Cutlery #92 talon. I like 1095, and I thought is would sharpen up easy, but it took me a while, and I cut myself badly in the process. I spent days obsessing about the edge(much of my arm hair hasn't grown back). Now this thing didn't have a good factory edge on it by any means, but...
Wait, I'm rambling. Here's the moral. If it came with a good edge(e.g. hair shaving) the most you should do is give it a little stropping. But for goodness sake, don't go nuts. If you think that the edge is sharp, it probably is pretty sharp, no matter what these esteemed gentlemen (not discounting their opinion by any means) tell you.
 
bpeezer said:
I wouldn't worry much about factory sharpening unless I had a Rockstead. No regular production company is going to give you an edge as good as you can give yourself.
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What he just said.
Many Higher end Japanese culinary knife companies do a superb job on their production knives but your european & american are usually fair to poor factory edges. It all comes down to dollars spent on man hours & abrasives used sharpening. When you purchased a new knife 100 years ago it almost never had a edge on it.
You did it yourself or the cutler you purchased the knife from did it.
 
I found my sharpener and killed the edge. Mostly flat ground means my clamp system is pretty much useless, apparently. Well damn.
 
dkb45 said:
I found my sharpener and killed the edge. Mostly flat ground means my clamp system is pretty much useless, apparently. Well damn.
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Not sure I understand that; I keep seeing this comment in relation to flat or full-flat grinds 'not working' with clamped setups, but it makes no sense. What clamping system are you using, and how are you normally setting up the clamp on your blades?

I normally found full flat grinds the easiest to clamp to, because the wide flats of the blade maximize clamping surface, and make for a very steady grip. The only caveat is, if one is still attempting to keep the two clamp sides parallel to each other; many will claim it's the only 'proper way' to do it, but that's only causing trouble for most blades. If trying to maintain the clamp parallel with a blade grind that isn't, the blade will pivot up & down in the clamp, and angle control is out the window. Easy solution is to keep both sides flush to the flats of the blade grind, maximizing surface area in contact. That'll keep the blade steady, and the edge will be crisp when finished. Never mind trying to maintain the clamp's two halves parallel, if only doing it to keep the 'angle setting' accurate. They aren't accurate anyway, in terms of actually getting the angle as indicated by the clamp.


David
 
Bob6794 said:
On a practice knife then you come back to this knife when you feel confident enough. No point in screwing up a nice knife.
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I guess I did things backwards when I learned, but it sure gave me motivation to get it right :D
 
bpeezer said:
I guess I did things backwards when I learned, but it sure gave me motivation to get it right :D
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When I first got my belt wander first thing I did was sharpen my nicest knife. To some it isn't a good idea, but it worked out fine for me. I have done free hand sharpening and I have used clamp systems a lot, I just want to,use a clamp system because my hands drift after some time, so while I may start at 15° I will end up around 20°, more difference using my right hand to guide because I am left handed. I would rather have somebody else do it consistently if I can't than get some abomination myself.

I plan on experimenting with soft rubber like neoprene to try and try to make the clamp system work better with a flat grind.
 
You might want to use 'preload' wrist that Heavy Handed advocates. When you get tired, you'll get shallower, not more obtuse, good luck!
 
I'm stupid and give up really easily only to come back shortly after and finish. I adjusted the clamp by tightening the screw less and the knob more, and that gave me the angle I needed to clamp decently securely to the flat ground blade. I apparently forgot how to triangles. Sharpened up now and the factory edge is unable to cut in comparison.

Guess the moral is that no matter how good the factory edge is you can get it sharper with the right tools, like the DMT Aligner/Magna-guide with coarse to extra extra fine stones and proper technique.
 
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