How to sharpen and hone a convex edge?

Stones is a lot harder technique than the stropping techniques on leather or a mousepad for convex edges. It's the recommended technique for convex edges from a number of sources, but perhaps most importantly, Mike Steward of Bark River Knife and Tool. He specializes in convex ground knives.

 

http://dlttrading.com/bark-river-sharpening-accessories.html  has their recommended equipment. Their green and black compounds are not like the standard green chromium dioxide compound. www.leevalley.com sells the same leather strop paddle which is where I got mine years ago.

 

Stropping technique:  http://www.youtube.com/watch?v=FQCkKPGSOtA

Almost all convexing is done with edge trailing (aka "strop") strokes only.  In fact, if you pull your blade off the end of the stone or strop, you'll reflexively roll the spine up and convex the edge.

 

Every freehand sharpener convexes to some degree, it's a function of inevitable "bobble" error.

 

If you're serious about convexing quit screwing around by trying to make unsuitable tools do the job.  Just as sand paper isn't the best choice for wiping your posterior, bench stones aren't the best way to convex.  Start stropping on materials with give.

 

In my opinion the benefits from convexing kitchen knife edges are minimal.  That said, there's no better way to determine whether something is a waste of time or not than by wasting time trying it.

 

There's nothing special about steeling a convex edge.  Just steel as usual on a fine or polished rod; certainly not anything aggressive enough to profile.   But you shouldn't steel on anything aggressive enough to profile anyway.

 

BDL

 

 

A (slack) belt grinder will certainly give you a convex edge.  Whether it's the right way to handle your kitchen knives is problematic. There's a lot to using a belt grinder, of which I know squat.  The guys I know who use them are tool junkies.  You might want to check out the Knife Forum, I know there are a bunch of belt sharpeners there.  Thom Brogan who posts at Fred's Cutlery Forum (as well as the KF) is a good person to help you get oriented.

 

Stropping is used for whatever you want to use it for.  Some people do it all on loaded and/or plain strops, some people reserve their strops for polishing.  Also, there are other kinds of strops than leather on wood.  When I strop it's usually to polish, and most of my stropping is done on charged balsa wood strops.  But I know and know of plenty of guys who do it differently and for different purposes.

 

If you're going to stay with knives made from the same sorts of alloys as your Messer, oil stones will do as good a job as water stones.  I have several sharpening kits, and recommend all the stones in my the oil stone kit.  They're excellent quality and a lot of bang for the buck as well.  They are:  Norton Coarse India; Norton Fine India; Hall's Soft Arkansas and Hall's Surgical Black Arkansas.  "India" is a Norton trade name, so it might have been redundant to include the manufacturer's identity, however the quality of Arkansas stones varies a great deal from quarry to quarry and manufacturer to manufacturer so "Hall's" is meaningful. 

 

At the end of the day, water stones are slightly more efficient sharpeners, oil stones are a little easier to maintain, and a good oil stone is less expense and longer wearing than a good water stone set.  But it doesn't make a huge difference.  FWIW, most of my water stone choices are overkill for Messermeisters.

 

A "true" double bevel isn't easy to sharpen, but a "micro-bevel" is about as easy as it gets -- provided you sharpen well enough to get a good edge underneath.  There's nothing wrong with a micro-bevel... you get all of the benefits of a double bevel at the expense of some extra maintenance.  I'm not saying a true double can't be done freehand.  It requires the same skill level as "thinning."  Heck, a double bevel is really the same thing as a single bevel edge on top of a thinned section pretty much.

 

When you're talking about a Messermeister chef's knife, you're really not going to pull much more performance out of it than doing your best to sharpen it at around 17* and not worrying about multi-bevels or convexing.  Get it thin, get it sharp, use a good steel between trips to the stones, and take it back to the stones when and as necessary.

 

If you must have a metal steel, RH Forschner rods are excellent and reasonably priced, rod hones.  Get either polished, fine, or the combo.  If you can afford it, the DMT CS2 12" ceramic rod is also very good.  It's got a metal reinforcement rod inside the ceramic and is nearly unbreakable.  The only drawback is that it comes (or at least  used to come) sloppy from the factory, and requires some light sanding to get the refectory "blow back" off.   

 

Hope this helps, 

BDL

I will admit that I find my belt grinder to be an indispensable sharpening tool.  I use water stones on my own kitchen knives but Germans generally get the belt treatment, as do many of my outdoors type knives.  I can sharpen half a dozen Wusthofs on my Kalamazoo grinder in the time it takes to soak my Chosera stones.  And the edge doesn't suck by any means; in fact, the results are often maddeningly good.  Maddening because when you get everything just right on the belts you get an edge that's soooo close to the best edges off of stones, and so much faster, that you almost wanna throw your stones down an elevator shaft.

 

Recently I picked up a used Moritaka from a member of another forum.  The edge was pretty beat up and the tip had a minor ding.  I've been so busy lately that I decided to whisper a prayer of forgiveness to the Knife Gods and put a "quick and dirty" belt edge on it so I could try it out, with the idea being to sharpen it properly a day or two later.  But coming off the leather belt the edge was really, really superb!  It's just sick how it cuts, and the edge retention is so good that I've grudgingly resolved to keep using it until it really needs re-sharpening.

 

Nothing beats a grinder for repairs and fixing really dull blades.  Quality aside, though, it does remove a bit more metal than is ideal for routine sharpening, although with practice you'll get to the point where that's no a very serious issue.  A convex edge is especially nice for softer steels as it adds a bit of strength to the edge.

 

My experience mirrors BDL's re the balsa wood strops- they work very well.  Stropping is probably superior to using a ceramic hone if portability isn't an issue.  Of course, it's hard to carry a charged strop around to and from work without contaminating it and getting compound on everything.

I concur. My Viel belt sander is a must for repair work, such as buzzing down sharp spine edges and reducing bolsters, or getting the initial burr on a seriously dull blade

 

I finish all other blades on other gear but meat or bone cleavers go all the way on the belts. I have a massive 8" bone cleaver in the que this week that is all kinds of messed up and will see a lot of the belts.

 

Jim

Another vote for the belt sander, before the belt sander I used stones since the early/mid 1990s Mine is the $30 Harbor Freight one. Touched up 3 work knives yesterday. Just a few minutes at half time between the Oakland-GB game.

To hone you can use a leather or felt belt that fits the sander.

 

Many converts came from stones, EP or other systems.

 

There's a lot of info at KnifeForums.

 

http://www.knifeforums.com/forums/showtopic.php?tid/776367/tp/1/

 

also

 

http://www.knifeforums.com/forums/showtopic.php?tid/862418/

 

 

Ignore this post, sorry. 

You'll love the EP.  It's a terrific tool.  The one suggestion I'd make is that you may want to look into upgraded aftermarket stones for it.

While the OP is moving away from convexed edges, I want to comment one thing further.

 

Convex edges are very easy to maintain and quickly regain sharpness. But you must maintain it frequently. Convex edges are a lot of work to restore from dull without power equipment. Don't let your convex edges go dull.

 

 

Thought I would add this series of tutorial videos on creating/maintaining non-mechanized convex edges.

 

http://www.knivesshipfree.com/pages.php?pID=4&CDpath=0

JohnR -- I just watched the first of those.  I love your use of the large model edges, and the camera angles when you move to the pad or the table top as stone.  Very well done, very clear.  More than the drawing pads I've seen in some other instructionals for the theory part.

To be clear I am not in the video and they are not my videos. I believe the person in the video won a contest that the vendor was having on the explanation of sharpening convex edges.

Thanks for linking then. I'd like to see more instructional with such perfect props!

FWIW I discovered convex edges a while ago when sharpening an old machete entirely by mistake. It seems due to the length and size of the knife and cramped conditions o had to work with at the time was causing me to unintentionally be slightly rolling the blade through half the stone. It oddly to me at the time worked extremely well and I have adapted this can we say technique to other softer steel tools as it does cause the edge to last a bot longer and be much less prone to having the edge roll or chip etc.

It feels a bit weird compared to the typical v edge where you trying to keep the blade at the same angle for the entire stroke across the stone.

I had never really thought about trying this on my kitchen Knives as I was always looking for improvements in sharpness etc but after viewing the bids in the links I am seriously intrigued (especially the one from Jon comparing many different high end Knives).

If my knife could scare off potato slices like that I know I would enjoy cutting them many times more than when the stick like frickin glue.

My question is if the loss of sticking is solely from a convex bevel? Just seems to simple.

I'd imagine convexing the blade face, or at least a portion of it behind the edge, would do better for food release than convexing the bevel. More experienced heads will chime in, I hope. Been thinking about this for one of my gyutos.

By that do you mean you may think the convex may need to extend further up the blade than the current bevel does, or am I just using bevel incorrectly?

I think you're using the term bevel correctly.  Yes, "extend up the blade".  The grind of some knives is convexed on the whole blade face. Or atleast behind the bevel. Above the bevel. It should be subtle, but not imperceivable. When you buy a knife that's right or left-handed, that might be the asymmetric bevel; it might be a d-shaped handle; or it might be the grind of the whole blade, that makes it so. 

Edited by Wagstaff - 12/22/11 at 12:05pm