Reprofiling M390 using Sharpmaker CBN rods

[TkoK83Spy]

I think I've sharpened my M390 Para 3 more than enough times now, that I think it's time to take it down to 15dps. I've got the CBN rods and used them successfully on an 8cr Kershaw for practice a few months ago. I was wondering if anybody else here has done the same with M390/204P/20CV?? If so, what can I expect...besides the obvious that it will take multiple sittings, as I imagine this will take a while. Any ideas/tricks to help it go smoother and quicker?

[A.S.O.K.A]

I dont have experience with M390, 204P, or 20CV. But, I have expereience in reprofiling steels, the most challenging being S90V. The most important thing is consistancy. You can do it faster, but speed can have higher risk for mistakes

[ZrowsN1s]

Im reprofiling the AEB-L Urban to 15dps right now. Even with relatively easy to sharpen steel, patience is key.

I also tend to sharpen heel to tip down and tip to heel up not letting the tip slide off the stone. Doing one side at a time. After a bit of practice you can speed the process up a little with this technique. Just check your bevels and make sure theyre even with eachother on both sides. Your essentially getting two passes for one. When I'm done grinding the bevel and onto the finishing phase I switch back to alternating downstrokes.

[TkoK83Spy]

Thanks Matt. I've seen videos of people doing one side until they create a burr, then I've seen others where they alternate with every stroke. That heel to tip, tip to heel...then you alternate to the other side and repeat the process back and forth?

[Cambertree]

Lance explains the 'circular' reprofiling motion using the diamond/CBN rods:

https://youtu.be/DI8lTj-F8gA

Also, if you don't already have a magnifying loupe, I highly recommend getting one. It sounds odd, but it's one of the best pieces of sharpening kit you can get to improve your skills and sharpening experience.

I like the bombproof 10x Belomo Triplet, which uses Zeiss glass.

[ZrowsN1s]

Thanks Matt. I've seen videos of people doing one side until they create a burr, then I've seen others where they alternate with every stroke. That heel to tip, tip to heel...then you alternate to the other side and repeat the process back and forth?

Yep. With the CBN rods I do one side until I've reprofiled it and I'm close to forming a burr. Then do the other side until close to a burr. Then I do the alternating sides downward heel to tip strokes only to finish. Then I switch to the brown stones, then fine, ultrafine depending on how refined I want it. And of course a little 1micron diamond paste on leather stropping.

The only real trick is keeping on eye on the size of the left and right bevels and trying to keep them even to eachother.

Lance's technique works really well too. He told me about it a while back on the forum when I was new to the sharpmaker. I switched to the way I do it because it leaves a scratch pattern I prefer, but the concept is the same. Keeping the knife on the stone and not wasting movement speeds up the process .

[TkoK83Spy]

Lance explains the 'circular' reprofiling motion using the diamond/CBN rods:

https://youtu.be/DI8lTj-F8gA

Also, if you don't already have a magnifying loupe, I highly recommend getting one. It sounds odd, but it's one of the best pieces of sharpening kit you can get to improve your skills and sharpening experience.

I like the bombproof 10x Belomo Triplet, which uses Zeiss glass.

Thanks for the link! I'll give that a try as well. Not really nervous, but feel there's no room for error attempting this on a sold out exclusive, over a $30 Kershaw I did this with before haha.

I do have a 10x loupe as well, which will be right by my side.

[ZrowsN1s]

I feel ya man, I wish I had gotten into sharpening before I got into nice knives. I wouldn't say I've wrecked any edges, but some definitely turned out less than perfect along the way.

[Sharp Guy]

:)

I actually did this to give me a much wider range of grits for touching up harder steels. For reprofiling I'd still prefer using my Hapstone but I may give it a go with this one of these days. I tried using the SM with the CBN rods a couple times and it was kind of a pain. I imagine this might be the same even with 120 grit SiC. I guess we'll see...

[Pelagic]

In any sharpening where I know a lot of work has to be done on any particular stone (or even a strop if I'm going for a highly polished edge), I'll normally do one side until it's forming an extremely small burr (as soon as you can notice it along the entire blade), then do the other side until it flips the burr to the other side. From there, I'll do a certain number of passes (the number varies depending on what I feel the situation calls for), we'll say 5 passes per side for a few rounds, then 3, then 2, the finally alternating passes until the burr is undetectable and I'm satisfied with the edge. Check for the apex reflecting light with a flashlight, strop each side with one pass on leather to see if there's any burr you couldn't see, test on newspaper, done.

I feel that alternating every pass takes a lot longer and requires more focus to maintain your perfect angle. But if there isn't much work to be done, I'll stick to alternating passes (or I may start with 3 per side or some other amount... Just based off intuition). Seems to work well.

[Cambertree]

Thanks for the link! I'll give that a try as well. Not really nervous, but feel there's no room for error attempting this on a sold out exclusive, over a $30 Kershaw I did this with before haha.

I do have a 10x loupe as well, which will be right by my side.

No worries, you can tape up the blade flats if you're concerned about errant scratches. Apart from that, it's just patience, focus and consistency, and not runnng your tip off the rods, as mentioned above. If you feel your focus diminishing, give it a rest and come back later when you're fresh.

The technique Pelagic mentioned above for finishing your edge is also very useful to combine with taking your other hand off the Sharpmaker. That way, you are forced to use very light passes to refine your apex.

Examine your edge frequently with the loupe and you'll be fine.

[JD Spydo]

I dont have experience with M390, 204P, or 20CV. But, I have expereience in reprofiling steels, the most challenging being S90V. The most important thing is consistancy. You can do it faster, but speed can have higher risk for mistakes

I've even found the old 440V ( S60V) to even be more stubborn to sharpen than S90V :D Which I guess is why it's such a great steel for Spyderedged serrations.
This thread confirms to me that we need one really coarse stone of some type for the 204 Sharpmaker. I've been shouting it out for at least 6 or 7 years now and with so many of these upper tier blade steels it's becoming almost a necessity IMO.
I reprofile my M390 Military on a coarse or extra coarse diamond benchstone before I even put it to the 204 Sharpmaker. Heck if I used the stones of the Sharpmaker to do a complete sharpening job on my M390 Military it would take me probably at least 2 to 3 hours to get it done the way I like it.
M390 has a stubbornness to it that is similar to the old 440V I just mentioned. To me it's even more difficult than ZDP-189.
But the final results are well worth it. It's been some time since I've had to do a complete sharpening on my M390 Millie because I usually fine tune it daily which is far better than letting it get banged up. But I'm getting that way with most of my blades.
We've said it many times here on this forum that the 204 Sharpmaker in it's present set up should be called the "Sharp-Maintainer" instead of the Sharpmaker.

[A.S.O.K.A]

I dont have experience with M390, 204P, or 20CV. But, I have expereience in reprofiling steels, the most challenging being S90V. The most important thing is consistancy. You can do it faster, but speed can have higher risk for mistakes

I've even found the old 440V ( S60V) to even be more stubborn to sharpen than S90V :D Which I guess is why it's such a great steel for Spyderedged serrations.
This thread confirms to me that we need one really coarse stone of some type for the 204 Sharpmaker. I've been shouting it out for at least 6 or 7 years now and with so many of these upper tier blade steels it's becoming almost a necessity IMO.
I reprofile my M390 Military on a coarse or extra coarse diamond benchstone before I even put it to the 204 Sharpmaker. Heck if I used the stones of the Sharpmaker to do a complete sharpening job on my M390 Military it would take me probably at least 2 to 3 hours to get it done the way I like it.
M390 has a stubbornness to it that is similar to the old 440V I just mentioned. To me it's even more difficult than ZDP-189.
But the final results are well worth it. It's been some time since I've had to do a complete sharpening on my M390 Millie because I usually fine tune it daily which is far better than letting it get banged up. But I'm getting that way with most of my blades.
We've said it many times here on this forum that the 204 Sharpmaker in it's present set up should be called the "Sharp-Maintainer" instead of the Sharpmaker.

I agree. The sharpmaker for most of the steels I use is more of a sharp maintainer, except when it comes to vg10 in my experience. I use an Edge Pro, I manipulate it to use other plates and rods like the sharpmaker diamond rods. Once in a while I will use the other sharpmaker rods on the Edge Pro. Some folks seem to have better luck using the sharpmaker to sharpen blades. But for the most part, I'll stick with the Edge Pro

[JD Spydo]

I dont have experience with M390, 204P, or 20CV. But, I have expereience in reprofiling steels, the most challenging being S90V. The most important thing is consistancy. You can do it faster, but speed can have higher risk for mistakes

I've even found the old 440V ( S60V) to even be more stubborn to sharpen than S90V :D Which I guess is why it's such a great steel for Spyderedged serrations.
This thread confirms to me that we need one really coarse stone of some type for the 204 Sharpmaker. I've been shouting it out for at least 6 or 7 years now and with so many of these upper tier blade steels it's becoming almost a necessity IMO.
I reprofile my M390 Military on a coarse or extra coarse diamond benchstone before I even put it to the 204 Sharpmaker. Heck if I used the stones of the Sharpmaker to do a complete sharpening job on my M390 Military it would take me probably at least 2 to 3 hours to get it done the way I like it.
M390 has a stubbornness to it that is similar to the old 440V I just mentioned. To me it's even more difficult than ZDP-189.
But the final results are well worth it. It's been some time since I've had to do a complete sharpening on my M390 Millie because I usually fine tune it daily which is far better than letting it get banged up. But I'm getting that way with most of my blades.
We've said it many times here on this forum that the 204 Sharpmaker in it's present set up should be called the "Sharp-Maintainer" instead of the Sharpmaker.

I agree. The sharpmaker for most of the steels I use is more of a sharp maintainer, except when it comes to vg10 in my experience. I use an Edge Pro, I manipulate it to use other plates and rods like the sharpmaker diamond rods. Once in a while I will use the other sharpmaker rods on the Edge Pro. Some folks seem to have better luck using the sharpmaker to sharpen blades. But for the most part, I'll stick with the Edge Pro

Before this year is over I've pledged to myself to get either an Edge Pro or a "Wicked Edge" sharpening system. I've had guys from both camps try to persuade me to get one or the other for almost two years now and at this point I'm leaning toward getting an Edge Pro because of the versatility advantages that a few users have told me about. But when I throw down a few C-notes to buy an advanced sharpening system I want to be relatively sure I've got the better of the two units.
I like any system that allows you to use other stones by other makers. Also it seems like I talk to more Edge Pro users that are satisfied than I do from Wicked Edge users. But that is barring any changes or improvements of either one in the meantime.

[jpm2]

:)

I actually did this to give me a much wider range of grits for touching up harder steels. For reprofiling I'd still prefer using my Hapstone but I may give it a go with this one of these days. I tried using the SM with the CBN rods a couple times and it was kind of a pain. I imagine this might be the same even with 120 grit SiC. I guess we'll see...

Where do you get those angled stone holders?
Do they have 1" x 0.25" slots?

[ShaneInDenver]

I actually did this to give me a much wider range of grits for touching up harder steels. For reprofiling I'd still prefer using my Hapstone but I may give it a go with this one of these days. I tried using the SM with the CBN rods a couple times and it was kind of a pain. I imagine this might be the same even with 120 grit SiC. I guess we'll see...

Where do you get those angled stone holders?
Do they have 1" x 0.25" slots?

I was wondering the same thing. Kind of looks 3d printed

[Sharp Guy]

Where do you get those angled stone holders?
Do they have 1" x 0.25" slots?

They're home brewed! :) and yes they fit 1" x 1/4" stones

[TkoK83Spy]

Nice job Pat! You've got some talent. Good to see you putting that to use. What else have you been messing around with?

[jpm2]

Where do you get those angled stone holders?
Do they have 1" x 0.25" slots?

They're home brewed! :) and yes they fit 1" x 1/4" stones

Those would sell...
I've always wondered why no one offered them. Been meaning to make some from wood or metal.

[Sharp Guy]

Those would sell...
I've always wondered why no one offered them. Been meaning to make some from wood or metal.

Yeah maybe. Problem is use isn't as easy as you'd think. There's a wide variance in stone thickness and it effects the angles. I noticed the same thing when I made the triangle bases for ZrowsN1s. Even though I tightened up the slots the angles still changed because the triangle stones are all a little different. Not much but it doesn't take much to make a significant difference. Pretty easy to correct with a little brass shim stock in the back though. But the amount of shim necessary changes for each stone/slot combination. It's even worse with the Moldmaster stones. Especially since you have to flatten them periodically. One of the Moldmaster stones in the grey base pictured actually has shims behind it to make it the same as the other side. I have 10 Moldmasters and one of them won't even fit the slots until I lap it. All others fit but some fit more loosely than others.

Gonna make a single slot (1" x 3/8") base to hold my double-sided Venev bonded diamond stones next. I don't want to buy another set. So I'll use 1 stone at a time and just flip it around to do each side of the edge.