sharpening m390 help

U

ubet

Joined
Nov 20, 2009
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I just got a benchmade 581 last week and had a few questions. The knife came sharp, but with a lot of grind marks on the edge, and two edges that arent even.... I havent re profiled it, yet. I took it to a med arksansas, then onto a spyderco fine ceramic whetstone, and it was duller coming off the ceramic than the ark. So I took it back to the med ark, then onto a black ark, and it was getting sharper with a shinier edge. Put it on a strop, and it seemed to lose its edge again. Whats going on here? Are the spyderco ceramic stones no good? I have had a tough time getting/keeping an emerson sharp with them. But this 581 will sharpen up on ark stones, but I go to a leather strop and it seems to dull.. any help would be appreciated.

Are the spyderco ceramic stones no good? I have had a tough time getting/keeping an emerson sharp with them too.

Does m390 take a polished edge, or like a rough edge?
 
M390 can definitely take a very fine, polished edge. As it happens, within the last week I've used my Edge Pro to rebevel (to 30° inclusive) and sharpen to a mirror finish two of my Spyderco M390 Mules.

Given that, I'm much more inclined to say what you describe is due to a technique issue rather than a problem with the stones or steel. You might be ending up with a wire edge on the Arkansas stones, but then knocking it off when you go to strop it or use the fine Spyderco stones.
 
ubet said:
I just got a benchmade 581 last week and had a few questions. The knife came sharp, but with a lot of grind marks on the edge, and two edges that arent even.... I havent re profiled it, yet. I took it to a med arksansas, then onto a spyderco fine ceramic whetstone, and it was duller coming off the ceramic than the ark. So I took it back to the med ark, then onto a black ark, and it was getting sharper with a shinier edge. Put it on a strop, and it seemed to lose its edge again. Whats going on here? Are the spyderco ceramic stones no good? I have had a tough time getting/keeping an emerson sharp with them. But this 581 will sharpen up on ark stones, but I go to a leather strop and it seems to dull.. any help would be appreciated.

Are the spyderco ceramic stones no good? I have had a tough time getting/keeping an emerson sharp with them too.

Does m390 take a polished edge, or like a rough edge?
Click to expand...


M390 is pretty easy to sharpen really, and yes it will take a very refined polished edge, but like most high alloy steels it will benefit for a coarser edge, it's a very agressive cutter.
 
i can't wait to finish my M390 mule so i can start using it. i have only heard good things about it.
 
I just reprofiled it, went from coarse nortons, to a med ark, to a black ark, then to the spyderco f, strop. It would push cut tp alright. Took it back to the black ark, to the spyderco, and it was a little better. Went back to the black ark, and it push cut through half a piece of 2ply tp. On my leg, with very light pressure it would shave it smooth, against the hair, not touching skin it would still cut hair. Any ideas on why the spyderco and leather strop are dulling passed where the black ark gets it. I am not the worlds best knife sharpener, but I can shave hair with an esee 5.

This damn spyderco stone though seems to dull everything. On them, to you go forward (edge to spine) or backwards (spine to edge) when sharpening on them?

Thanks
 
Ankerson said:
M390 is pretty easy to sharpen really, and yes it will take a very refined polished edge, but like most high alloy steels it will benefit for a coarser edge, it's a very agressive cutter.
Click to expand...

Could this be why the spyderco/leather strop seems to dull it?

I noticed, it sharpened rather quickly...
 
ubet said:
Could this be why the spyderco/leather strop seems to dull it?

I noticed, it sharpened rather quickly...
Click to expand...

I would still be inclined to think that a wire edge is the problem. I had no problem doing a re-profile on my M390 710 knives and both took a polished edge quite nicely. What I found was that a light touch on the stones seemed to work better.
 
Ok, after reading up on how to get rid of a wire edge I took it to a piece of oak, and cut cross ways. Came back in the house, push cut some toilet paper. Then another piece I seperated the plies and push cut this one ply.

IMAG0060-1.jpg


The tear at the end happened when I separated it to take the picture.

The toilet paper is the cheapo walmart brand...
 
The only times a strop would dull an edge is either when you use too much pressure and the strop "curves" around the edge and dulls it, or if your edge wasn't refined enough prior to stropping, and the strop merely took off the teeth.
 
might try lighter touch with the strop. also could be missing the edge when stoning it. i try for a 30inc or lower backbevel when i do a reprofile by hand and finish with a bit of a micro bevel at the edge something a bit more than 30 up to 40 depending on what steel im working with. i do strop mine pretty hard though as i like the edge to form into a more convex profile. i always end with real light stropps on the edge and almost all the time i get hair popping results and a nice polished edge.
 
ubet said:
I just got a benchmade 581 last week and had a few questions. The knife came sharp, but with a lot of grind marks on the edge, and two edges that arent even.... I havent re profiled it, yet. I took it to a med arksansas, then onto a spyderco fine ceramic whetstone, and it was duller coming off the ceramic than the ark. So I took it back to the med ark, then onto a black ark, and it was getting sharper with a shinier edge. Put it on a strop, and it seemed to lose its edge again. Whats going on here? Are the spyderco ceramic stones no good? I have had a tough time getting/keeping an emerson sharp with them. But this 581 will sharpen up on ark stones, but I go to a leather strop and it seems to dull.. any help would be appreciated.

Are the spyderco ceramic stones no good? I have had a tough time getting/keeping an emerson sharp with them too.

Does m390 take a polished edge, or like a rough edge?
Click to expand...

These other folks will give you more direct instructions, but I'll just note that I've used Sharpmaker stones to get rid of grind marks a Benchmade M390 bladed 710 with good results. I don't polish my edges, so I wouldn't know about that. I normally use DMT stones to sharpen. I do know that after using an X-tra fine DMT stone, a Benchmade M390 blade held an edge better than anything I've ever seen except CPM M4, and it tied that one.

side comment:
Benchmade does an excellent job with M390, no matter what numbnuts says. I may have to put him on ignore.
 
knarfeng,

Ive noticed it holds an edge really good. I have tried stropping it different ways, and just cant seem to get it to work on this blade, its gotta be me.... but on the black ark it gets damned sharp.
 
My EDC 755 MPR has been 'touched up' several times on my Spyderco Sharpmaker's white file edges. The key is frequently changing the edges - and cleaning them, too. It is razor-shap then, so the white file's flats are not used. I've added several more M390 BM's - the 480-1 and 581 - since then.

Stainz
 
If you have a good quality hard black Arkansas stone (Norton or Dan's) it should be finer than a fine Spyderco ceramic stone. The ultrafine Spyderco is comparable to a strop in how smooth the finish it will produce.
I would use the fine ceramic stone before the strop, in place of the hard Arkansas. If you want an even finer edge, finish with the black hard
Arkansas and then follow with a fine strop. The Spyderco ceramic stones require very light pressure. If you press too hard, you will produce a
wire edge.
I am often satisfied with finishing a knife edge with the fine ceramic stone, and then a coarse and a fine strop. I use a hard Arkansas stone for
sharpening tool blades, like chisels or plane irons.
 
Try using Balsa wood with a light touch, and ultra fine compounds for stropping.
It works far better for me than leather. :thumbup:

Ben
 
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