Some Sebenza newb questions- sharpening and maintenance

[Darth Detori]

Hey there!

I got my Small Sebenza 21 on wednesday and I LOVE it! As I've used it over the past few days, however, A few things have come up that I need answers to. THIS IS NOT A BASH IN ANY WAY! Please don't take it as such!

First, I'm having trouble sharpening the blade and keeping an edge. After my first day of using it, which largely was cutting lemons on a cutting board, the belly of my blade was dulling (not dull, but not that sharp either). Now I like to keep my blades INSANELY sharp, and I've been able to do this using my Smith's sharpening kit (the one that holds your blade in place and has the sharpeners on rods to keep a consistent angle) and stropping it. I tried for a while to get it really sharp at 40 degrees and I just can't get it crazy sharp. I have no trouble doing this on any of my spydercos (at 30 degrees though), and the blade was never really that dull to begin with. Cutting stuff now leaves a jagged edge and requires a bit of force to get the cut going. I'm used to 30 degree angles, and I'm thinking about grinding it down to one, however if I'm having edge retention issues now that would seem to just aggravate the problem. Why am I having an issue?

Second, and this is probably an obvious answer, I work at a restaurant and I cut a lot of lemons, limes, tomatoes, etc. so I clean my blade off immediately after. Knowing that titanium is really rust resistant, I didn't worry if I was getting a little bit of water around the pivot. Soon thereafter, opening felt a little bit gritty, then the action got a bit tighter to the point where it's difficult to thumb flick it open. The obvious answer, to me, would be that my knife isn't broken in to the point where this won't effect it, and that the water is washing out the lube. Does this seem like sound reasoning?

I'd ask these questions directly to CRK, however I know they're closed on the weekend and would really like some answers.

Now it's time to open her up and re-oil!

 

[MORIMOTOM]

the edge angle is closer to 30 degrees than 40. at least that is the setting i use.

yes, the water washed out the lube.

 

[SuzukiGS750EZ]

I can't answer your sharpening question, but I can answer the pivot question. Citrus is a natural degreaser, so you may very well be washing away the grease before the water even hits it. Or, the citrus' sticky nature could be getting trapped in there. Did you buy the CRK grease with the knife for maintenance?

 

[Darth Detori]

I can't answer your sharpening question, but I can answer the pivot question. Citrus is a natural degreaser, so you may very well be washing away the grease before the water even hits it. Or, the citrus' sticky nature could be getting trapped in there. Did you buy the CRK grease with the knife for maintenance?

That makes sense. And I didn't buy the CRK grease; I'll get some when I send in my knife next month to get dual thumb lugs installed.

 

[never too sharp]

After my first day of using it, which largely was cutting lemons on a cutting board, the belly of my blade was dulling (not dull, but not that sharp either).

CRK's S30V is, in my reckoning, a little soft. So you may have to sharpen it a little more often. Not really a bad thing, though.

Second, and this is probably an obvious answer, I work at a restaurant and I cut a lot of lemons, limes, tomatoes, etc. so I clean my blade off immediately after. Knowing that titanium is really rust resistant...

Titanium is rust resistant. In fact, I don't think it will rust at all. The bronze bushings, however, may experience some corrosion, bronze being made of copper and tin. So water and air will corrode the bushings, something the CRK flourinated grease will help prevent. Order up some grease, rip that sucka apart, then polish and grease the bushings. it will be smooth as silk.

 

[MORIMOTOM]

ti will not rust and i dont think it will corrode.

iron causes rust, and there is no iron in titanium or its alloys.

(right?)

 

[OldDude1]

Greetings: I believe the condition you have encountered regarding your Sebenza retaining an extremely sharp edge is not uncommon. You may wish to read this thread in it's entirety for a full debate on both the perception of retained edge sharpness and the purported causal factors. http://www.bladeforums.com/forums/showthread.php?t=747912&highlight=s30v+hardness

Regarding why the belly of a Sebenza may seem hard to sharpen. You may wish to read posts 1 through 20 of this thread. http://www.bladeforums.com/forums/showthread.php?t=740050&highlight=building



Regarding other "Issues" What some of us see as short comings, others see as assets. OldDude1

 

[Darth Detori]

Thanks for the links! Your info in that thread was excellent. I'll have to come back to it specifically when I get a sharpmaker, however it was eye-opening on how the tip/belly is convex- I knew something was different about it but couldn't place what.

I brought it to 15* then put a 20* edge on it- it's exactly where I like my knives to be in terms of sharpness right now, at least in terms of how sharp I can make it with the tools I have at hand. Next month's knife purchase is going to be a sharpmaker with ultra fine rods, so I can get that insane edge on it.

 

[OldDude1]

Perhaps you will be able to manipulate the laws of physics better than I can. An "insane" edge can of course be applied to your Sebenza but you may find it somewhat frustrating trying to keep it that way. The current heat treatment produces a blade hardness of 58 to 59 RC. This hardness level reduces the propensity for the steel to chip when used but, in doing so, it necessarily allows the edge to more easily roll. The Sebenza is designed for comparatively hard use. In a hard use knife, the longer a blade retains a FUNCTIONALLY useful edge, the longer it can keep cutting before sharpening is required. A harder blade can KEEP an "insane" edge longer, but only if it is not subjected to forces which can readily chip the comparatively harder but more brittle steel. One or two blade chips and the knife is no longer FUNCTIONALLY useful. The physical structure of the S30v steel makes it quite resistive to abrasion. This further extends the FUNCTIONAL life of it's edge. Unfortunately the steel doesn't care whether its' resisting abrasion from whatever you are cutting or its' resisting abrasion from your sharpening stones while you are trying to reapply an "insanely sharp edge. The Sebenza will TAKE an "insane" edge but it will quickly degrade through rolling into a functionally useful, very long lasting, albeit less razor like edge. Because of it's abrasion resistance, the S30v will take a bit more effort in returning it to an "insane" level of sharpness than a less resistive steel. Constantly keeping an "insanely" sharp edge on an frequently used Sebenza requires a goodly amount of frequent attention. You may find that a functionally sharp or very sharp, or just plain sharp edge on your Sebenza is more than adequate for your purposes. If not, there are other means of addressing your requirements. A factory stock S30v Sebenza ,although an EXCELLENT knife, may not fully be one of them. The foregoing is only my opinion. OldDude1

 

[kawr]

Is it possible to maintain the Sebenza edge with just a leather strop + compound or is it best to use the sharpmaker like Chris Reeve suggests?

 

[marthinus]

Is it possible to maintain the Sebenza edge with just a leather strop + compound or is it best to use the sharpmaker like Chris Reeve suggests?

You can maintain the edge on a strop. I did for the first month of my Insingo and then decided to use the fine rods on my Lansky Turn Box kit (not as great as the sharpmaker) just before hunting (dont want to struggle in the field with a slight dull edge ) but I have been maintaining the edge after that only on a strop the past week.

Personally I only use the fine rods after a days work and I can see the edge rolled a bit. I use a fine diamond lansky paddle sharpener if I slice through paper and there is a small 'holdup' through the cutting motion. Other then that the strop sees the most work to get the edge polished and shaving sharp. (I have shaved with my old small Sebenza but not yet with the Insingo)

 

[OldDude1]

Greetings Kawr: Stropping, based upon my limited level of expertise, is a final refinement of an already fully established and highly sharpened edge. Stropping can however cosmetically polish a less than truly sharpened blade. In expert hands. on an appropriate backing, a knife can be "maintained" for a period of time just by stropping. In practice, the Sharpmaker rods have been more effective for my personal "maintenance" needs. Few of us wish to remove more metal than is absolutely necessary to obtain the desired result. But, sufficient metal must be removed to reestablish the cutting edge. This often means using the fine, or if needed, the medium then the fine Sharpmaker rods. Correctly performed stropping is the final step. If you are not yet sufficiently adept at stropping, it may not yield the same return for the effort expended on the Sebenza as it might on other blades and steels. Of course this is just my opinion. OldDude1

 

[Harry Callahan]

The Seb is a fantastic knife, congrats on landing one. But if you work in a professional kitchen environment there are better choices. The Sikayo is CRK's kitchen knife and it absolutely ROCKS. Doesn't get much talk time around here as the Seb pretty much hogs the spotlight (not such a bad thing I suppose). The Sikayo is quite possibly the ultimate production kitchen knife. I wouldn't recommend getting caught cutting up food with a folding pocketknife of any kind. A health inspector would have a seizure on the spot. Just thinking about whatever lube you used on the pivot being bled over into my tomato slice is pretty much a turnoff. Use the Seb as a pocketknife. Cut your customer's onion slice with a Sikayo.

Now, on to the subject of maintaining your Seb's edge. Get a DMT hone. I recommend the black one (ultra course). As life goes on these DMT stones lose their pizzaz so it's always good to go with the coursest one you can get. Use the DMT stone to get going. Then move on to your Smith's system (which sounds alot like a Lansky). Then finish off with the Sharpmaker's white stones set at 40 degrees. On this final step it is CRITICAL that you use almost impreceptable pressure. Basically just touch the stones on the way down. About two hundred strokes or so. Real slow and careful. Any kind of "real" pressure and you'll end up with a wire edge folded over to one side. You should be able to push cut paper effortlessly if you do this final step correctly. If you start to get a wire edge, go back to the DMT for a quick couple of strokes. You'll get the hang of it. It's worth the effort. The Seb is a great pocketknife. Cheers.

 

[kawr]

Greetings Kawr: Stropping, based upon my limited level of expertise, is a final refinement of an already fully established and highly sharpened edge. Stropping can however cosmetically polish a less than truly sharpened blade. In expert hands. on an appropriate backing, a knife can be "maintained" for a period of time just by stropping. In practice, the Sharpmaker rods have been more effective for my personal "maintenance" needs. Few of us wish to remove more metal than is absolutely necessary to obtain the desired result. But, sufficient metal must be removed to reestablish the cutting edge. This often means using the fine, or if needed, the medium then the fine Sharpmaker rods. Correctly performed stropping is the final step. If you are not yet sufficiently adept at stropping, it may not yield the same return for the effort expended on the Sebenza as it might on other blades and steels. Of course this is just my opinion. OldDude1

Makes sense, I already have a Spyderco Sharpmaker so I guess I'll just stick with that. Great info, much appreciated.

 

[Slim to None]

A good chromium oxide loaded strop will definitely reduce the number of sharpenings you'll need. One of the best investments I made in knife collecting.

 

[Wyldey]

OldDude1 speaks a lot of sense, "scary sharp" edges that can whittle hairs sound nice and impressive but it's very limited in practicality lest that be all you intend to do with your sebenza. A Seb can be sharpened to that degree but it wasn't designed for that. It's a great general utility blade steel at it's present hardness with the hollow grind and sufficient blade stock behind the edge to make it tough, making the edge too acute is possible to achieve scary sharp but not what the seb is about and if you actually use the knife you probably won't be satisfied with how the scary sharp edge wears.

About stropping I'd recommend practice on something else first if you've never done before, mark the edge with a marker, it's easy and yet frustrating if you can't figure it out, light strokes knowing the right amount of pressure and the proper medium (strop, backing and compounds etc) and a lot of people don't realize they aren't actually hitting the edge (hence the marker technique) when they try stropping, blade geometry makes the classic and 21 easier to strop imho, shallower belly vs deep belly in some other blade deigns, the factory grind however is not even and would quite likely have to be reprofiled if you want to strop smoothly, that of course won't matter if your edge has already been reprofiled from repeated sharpening.

The sharpmaker is good sharpening system for general edge maintenance, I use the 30/40 secondary/primary bevel angles as per general sharpmaker user instructions that come with the kit and finish off with light stropping using BRKT green compound and strop. That works for me and I'm happy with my results.

 

[sjhong]

A quick question to the OP: is there a reason why you use a pocket knife in the kitchen?

 

[viva la]

I work at a restaurant and I cut a lot of lemons, limes, tomatoes

get a paring knife, or a small chefs knife. You shouldn't be using a pocket knife esp on food that will be served raw to customers. It is unsanitary, unsafe, and unprofessional.

use this instead:

 

[Sidman]

There is a SMALL chance that this may play a role. What are you using for a cutting board? If it is glass or marble, you will dull any blade in about 3 cuts.

Be sure you use only wood or thick plastic cutting boards. Hope this helps

 

[Sidman]

That makes sense. And I didn't buy the CRK grease; I'll get some when I send in my knife next month to get dual thumb lugs installed.

Oh and be careful what you put on your blade for lube and protectant....most are poisonous. You can get a jug of "Mineral Oil" in the, ahem, laxative section of your drug store (for ~$3 ). OR, if you don't mind the smell, check out the ingredients list on J&J Baby Oil.....(1) Mineral Oil (2) Fragrance (that's all)

P.S. Use the Mineral Oil on your wooden cutting boards too. Waaaaay cheaper than that stuff made-for-cutting-boards-and-wooden-counter-tops. (obviously use it on your wooden handled knives too)

P.P.S. It washes out of clothes in the normal laundry cycle!!!!!!