I need help/advice Sharpening M390

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rgrad80
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I need help/advice Sharpening M390

#1

Post by rgrad80 »

Hello and thank you for reading my thread. I have a Sharpmaker with the brown stones, fine and ultra fine stones.
I started sharpening my own knives about two months ago. I thought I was getting the hang of it. I can put a wicked edge on 52100, S30v/35v, 8cr13mov, and all of my wife’s kitchen knives.
Tonight, I sat fown to sharpen a knife I had just purchased used in M390. I knew it was going to come dull, and that was fine, because I was looking forward to sharpening it:)
I started with the brown stones at 30 degrees doing alternating passes for about 20 passes on the narrow and then wide side. I repeated this process through the ultra fine. I stropped the blade on a 2 micron and finished with .5 microns on leather. The knife was still incredibley dull and it would not shave arm hair at all. In fact, it doesn’t even cut paper that well. My “crappy” Tenacious puts the M390 blade to shame...by a lot.

Please help. What am I missing? I stopped messing with the blade, because I didn’t want to mess up the knife.
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Woodpuppy
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Re: I need help/advice Sharpening M390

#2

Post by Woodpuppy »

Use a sharpie marker on the edge bevel and go to the medium stones again to see if you’re actually hitting the apex of the edge. If the knife is excessively dull or was sharpened at a lower angle, you’re still grinding back the bevel to 30 degrees. The marker will show you. You might find the 20 degree setting gets you a sharp blade and you’ll need to decide if that’s good enough or if you want the thinner edge.
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Re: I need help/advice Sharpening M390

#3

Post by Sharp Guy »

^ Yep! What Woodpuppy said!

My guess is you're not hitting the apex. I would sharpie the edge and use the medium (brown) stones set on the 40° side. Sharpen until you have a clean apex (sharpie gone from the very edge) and it feels sharp, cuts paper smoothly, etc. Then you can further refine on the fine stones.

I've only touched up the factory edges on my M390 & 20CV knives. As far as I can tell the bevels are about 30° from the factory. I used the 40° setting on the SM and they were pretty easy to get sticky sharp. Very similar to sharpening S30V maybe even a little easier.
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Tucson Tom
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Re: I need help/advice Sharpening M390

#4

Post by Tucson Tom »

Using the sharpie should tell the tale. You ought to be able to get it "decently sharp" just with the brown stones. If you can't get that to happen, there is no point refining the edge (or trying to) with the other stones. If the brown stones aren't cutting all the way to the edge, you have to keep at it until they do (essentially reprofiling the blade perhaps). Then the other stones can do their work.

My guess is that the blade was sharpened at some more obtuse angle and the stones are not getting to the edge at 30 degrees. The sharpie will tell. If you have a lot of metal to remove, you may be pretty frustrated trying to do it even with the brown stones.

When you say you know it was going to come dull, that is a strong hint that it isn't a Spyderco knife. I have had knives from other makers that have been sharpened poorly and at somewhat random angles. You may be wishing you have diamond or CBN rods if you have a lot of work to do. The suggestion of trying the sharpmaker set a 40 has merit and might save you a lot of work, but see what the sharpie says with the sharpmaker at 30 first.
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Re: I need help/advice Sharpening M390

#5

Post by KnickKnackCity »

Sharpie was honestly a pivotal moment in my progression with the sharpmaker. Once you familiarize yourself with visual representation you can move onto feeling what you are doing woth each pass.
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Tucson Tom
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Re: I need help/advice Sharpening M390

#6

Post by Tucson Tom »

Also, I hope it is clear that it is not the steel that is giving you trouble, but the blade geometry.

Well, I guess it is always possible that if the knife is not a Spyderco, there are issues with the steel, but I think that is really really unlikely.
rgrad80
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Re: I need help/advice Sharpening M390

#7

Post by rgrad80 »

Tucson Tom wrote:
Mon Oct 22, 2018 9:25 pm
Also, I hope it is clear that it is not the steel that is giving you trouble, but the blade geometry.

Well, I guess it is always possible that if the knife is not a Spyderco, there are issues with the steel, but I think that is really really unlikely.
Still learning for sure. The sharpie trick is probably going to help me a bunch.I bet I was working away but not really getting to the meat of the problem with the blade. I would have never thought to use a sharpie. You guys truly are great at helping out.
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Re: I need help/advice Sharpening M390

#8

Post by legOFwhat? »

I would add a jewelers loupe or magnifying glass to go along with the sharpie. Being able to see what's going on at the edge helps me so much! Good luck!
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awa54
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Re: I need help/advice Sharpening M390

#9

Post by awa54 »

What they all said! M390 isn't a difficult steel to sharpen, but reprofiling on the Sharpmaker with just the brown rods can be a long tedious task :(

You really ought to get a coarse bench stone or at least the Diamond or CBN rods for the Sharpmaker, it might take literally hundreds of passes to re-bevel a blade with the medium rods!

Idahone also makes very coarse (100-200 grit) ceramic rods that fit the SM and Congress tools have a number of coarse triangle rods that can work on the SM (though a bit shorter than stock, a slightly sloppy fit and all wear much faster than ceramic).
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rgrad80
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Re: I need help/advice Sharpening M390

#10

Post by rgrad80 »

awa54 wrote:
Mon Oct 22, 2018 10:05 pm
What they all said! M390 isn't a difficult steel to sharpen, but reprofiling on the Sharpmaker with just the brown rods can be a long tedious task :(

You really ought to get a coarse bench stone or at least the Diamond or CBN rods for the Sharpmaker, it might take literally hundreds of passes to re-bevel a blade with the medium rods!

Idahone also makes very coarse (100-200 grit) ceramic rods that fit the SM and Congress tools have a number of coarse triangle rods that can work on the SM (though a bit shorter than stock, a slightly sloppy fit and all wear much faster than ceramic).
Thank you! Super good info.
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Bloke
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Re: I need help/advice Sharpening M390

#11

Post by Bloke »

Nothing to really add other than to say you can also with the SharpMaker set up, lay a strip of paper on the sharpening rod and hold it there.

Take the knife to the rod with the paper on it and run the blade down as you normally would when sharpening.
If the blade grabs the paper and wants to cut it you’ll be grinding to the apex. If it slides don’t the paper without biting into it and wanting to cut it you’re still grinding an obtuse bevel.

Hope this makes sense. :)
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Re: I need help/advice Sharpening M390

#12

Post by Bill1170 »

Bloke wrote:
Mon Oct 22, 2018 11:23 pm
Nothing to really add other than to say you can also with the SharpMaker set up, lay a strip of paper on the sharpening rod and hold it there.

Take the knife to the rod with the paper on it and run the blade down as you normally would when sharpening.
If the blade grabs the paper and wants to cut it you’ll be grinding to the apex. If it slides don’t the paper without biting into it and wanting to cut it you’re still grinding an obtuse bevel.

Hope this makes sense. :)
That’s a good trick, backup for when I’m out of Sharpies. Some posters seem to have missed that the dull knife in question was a used knife, not a new one. The diamond or CBN rods are much faster than the brown rods, but are easily ruined by too much pressure being applied. I reprofile freehand on diamond benchstones, it’s much faster.
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Re: I need help/advice Sharpening M390

#13

Post by ZrowsN1s »

rgrad80 wrote:
Mon Oct 22, 2018 10:29 pm
....
Thank you! Super good info.
You might check out this thread for pointers
http://www.spyderco.com/forumII/viewtop ... =2&t=80985
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Woodpuppy
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Re: I need help/advice Sharpening M390

#14

Post by Woodpuppy »

ZrowsN1s wrote:
Tue Oct 23, 2018 1:30 am
rgrad80 wrote:
Mon Oct 22, 2018 10:29 pm
....
Thank you! Super good info.
You might check out this thread for pointers
http://www.spyderco.com/forumII/viewtop ... =2&t=80985
Good idea, this has all been recommended before. Several of us posting in this thread are relatively new members here passing along what we’ve learned from “our elders”. We’re excited to be the ones to help this time around!

I’m one who started with bench Arkansas stones but find I get more consistent results with the sharpmaker. Reprofiling is no fun on it though. I cheated and laid a diamond plate from another system against the sharpmaker rod and held the bottom of the plate against the base of the rod with a toothbrush. That made reprofiling an obtuse Benchmade 210 much, much faster. Now that knife I’d named “Nemesis” because I never could get it sharp. In reality I was experiencing the same thing you’re describing here, I was not removing materiel to the apex. Once I started using the sharpie trick and was getting my other knives into scary sharp territory (somewhere beyond shaving, into cuts when touched by accident), I went back to my old nemesis, reprofiled it to 30 degrees, and will get a custom pocket sheath made for it to actually use it.

Hope this all helps, the sharpie and hand lens will show you where you need to work on the blade and will make a big difference quickly in your abilities.
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Re: I need help/advice Sharpening M390

#15

Post by rgrad80 »

Woodpuppy wrote:
Tue Oct 23, 2018 4:38 am
ZrowsN1s wrote:
Tue Oct 23, 2018 1:30 am
rgrad80 wrote:
Mon Oct 22, 2018 10:29 pm
....
Thank you! Super good info.
You might check out this thread for pointers
viewtopic.php?f=2&t=80985
Good idea, this has all been recommended before. Several of us posting in this thread are relatively new members here passing along what we’ve learned from “our elders”. We’re excited to be the ones to help this time around!

I’m one who started with bench Arkansas stones but find I get more consistent results with the sharpmaker. Reprofiling is no fun on it though. I cheated and laid a diamond plate from another system against the sharpmaker rod and held the bottom of the plate against the base of the rod with a toothbrush. That made reprofiling an obtuse Benchmade 210 much, much faster. Now that knife I’d named “Nemesis” because I never could get it sharp. In reality I was experiencing the same thing you’re describing here, I was not removing materiel to the apex. Once I started using the sharpie trick and was getting my other knives into scary sharp territory (somewhere beyond shaving, into cuts when touched by accident), I went back to my old nemesis, reprofiled it to 30 degrees, and will get a custom pocket sheath made for it to actually use it.

Hope this all helps, the sharpie and hand lens will show you where you need to work on the blade and will make a big difference quickly in your abilities.
I’m ordering a few more stones for the Sharpmaker today...along with a 3 pack of Sharpies. I could send the knife in to get sharpened, but that wouldn’t help me long term. You guys are great at giving detailed information. I went back and read the other thread that was linked...helped a lot.
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Re: I need help/advice Sharpening M390

#16

Post by Chumango »

In the absence of coarse rods, you can clip sandpaper to the rods you have for quicker stock removal, then use the rods alone when you get to the apex.
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Re: I need help/advice Sharpening M390

#17

Post by JD Spydo »

My main EDC is an M390, C-36 Military model which I'm extremely fond of and find it to be a great EDC. Since I've moved up to the Supersteels on my Every Day Carry folders (EDC) I've resigned myself to the fact that using diamond benchstones for quicker stock removal is truly a great way to go. Then when you get out your 204 Sharpmaker all the hard work is done then you can get down to the fine tuning of the apex. AS good as most of these newer/better blade steels are it's time we all realize that owning diamond sharpening tools is really a fact of life.

However I have wondered why Spyderco ( or anyone who makes compatible stones for the 204 Sharpmaker) hasn't come out with a coarse or extra-coarse stone in Aluminum Oxide or Silicon Carbide for quicker stock removal. It's about the only weakness that the 204 Sharpmaker has at this point.
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