Need MORE sharpening Advice

K

Kezon

Joined
Sep 19, 2000
Messages
20
First off thanks to those that answered questions in my last post on what DMT's I needed. I just got the Razor Edge Book of Sharpening from the library Friday after placing it on hold. I read through most of it this weekend and now i'm even more confused as to what I need
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. They talked about relief, primary blade, secondary, etc, do these things also apply to convex edge? I'm not sure exactly how I'm going to structure this post so bare with me.

I guess the main thing right now I'm confused about is the different sharpening methods and what they'll do for my knife edge. BTW I want to primarily use the set-up for the Fallkniven F1 I'm buying.

Strop: Cliff recommended a compound from Lee Valley to apply to piece of leather. But by using the strop what am I doing to the knife? Sharpening the edge, polishing it or realigning it? Would a steel do the same thing such as Raz-R-Steel from Razor Edge Sharpening Syetms(RES)?

DMT: If I had one of the butterfly type with extra-fine and fine on either side, would this be similar use as a steel or strop? Or for grinding/reprofiling the blade?

RES: This includes course and fine stones with that smooth steel and guides. This seems like the perfect system for me but I think I may have been just SLIGHTLY influenced by there book. I wonder if I could not use the guides and maintain a proper convex edge by freehanding on stones and then steel as needed to maintain the edge?

If you can offer any advice its greatly appreciated. From what little I know right now I would just get the RES and try it freehand and use the smooth steel to maintain. Sergiusz Mitin mentioned in my last post that using the Spyderco benchstones would keep the convex edge so I'm hoping the RES ones will do the same since there cheaper. The strop looks really good too and I probaly would buy the necessary compund and leather as well since it may add to the edge. I'm not sure about the DMT's because I don't really understand the role they fill and if there needed in my setup.

I was going to use this setup for backpacking as well as at home but right now I just want to get a setup that will sharpen to a shaving edge.

If you think what I'm thinking of doing is stupid please let me know and if its good please tell me. Or just offer some advice.

All advice greatly appreciated,
Derek

 
A smooth steel only realigns an edge. It is smooth and non-abrasive. If usage of a convex edge has been light a steel will realign it. A leather strop with no added abrasive will mostly realign an edge with some polishing. A really hard alloy will be minimally abraded by the minor grit found in the leather. Anything else is going to be an abrasive process where you are removing material from the blade.

When Cliff suggested stropping a convex edge on leather with an abrasive compound it is primarily a honing process with material removal. It will follow the existing blade contour and polish the side of the blade and restore the edge--mostly. The softness of the strop may cause it to slightly wrap around the cutting edge and round it slightly. I like to follow the stropping with a few strokes on a fine ceramic stone to thin the last sixteenth of an inch of edge.

Anything with diamond abrasive, whether it folds or not, is definitely abrading an edge much more than aligning. If you use just a couple edge-trailing honing strokes on extra-fine diamond abrasive you may remove some folded-over burrs on your edge. They will primarily be cut off rather that realligned.
 
I'll try to help you out as best I can. If you need anything I say here clarified feel free to e-mail me, sharpening is my favorite part of my favorite subject.

First off I think you may be overthinking the process. All you do when you sharpen a knife is get the two bevels of your edge to meet as closely as possible. How you get to that point is for the most part unimportant. You could start an edge with a brick if you were so inclined. The tools are much less important than the skill of the user in my experience. Good tools certainly help, but they're still useless without skill. What is most important is having a good smooth stone to finish the edge with.

Strop: What you're doing with a strop is primarily polishing. The reason you want to use the strop on a convex edge is because it will follow the contour of the slightly rounded convex bevel. A flat stone will produce a flat bevel. A strop is nice because the more polished an edge is, the longer it will stay sharp and it will feel much sharper.

DMT: Diamond stones are primarily used for grinding. These will remove very significant amounts of metal quickly. This can be good and bad. You don't want to use these unless the edge is damaged and you need to take off a lot of metal.

Razor Edge: If you want to maintain the convex edge, this isn't what you want. As I said before, a flat stone such as this will give you a flat bevel. This isn't neccesarily a bad thing, just different. Convex edges are hard to get right. If you can get it right though, it's awesome.

So bottom line, you're on the right track, just not for a convex edge. As I understand it, convex edges are applied using a belt grinder. The belt is slightly slack, and when used to put an edge on a knife it makes the bevels slightly convex. The only drawback is that those machines run into the thousands of dollars. You can get a poor man's convex edge with a little work. You can use a sanding belt to get the edge without the machine. If you secure the belt so it is just slightly slack, you can grind the edge in a stropping motion and get a convex edge. Another solution is to attach sheets of sandpaper to pieces of styrofoam and use the same stropping motion. The styrofoam gives a little and makes the bevels convex. These methods are quite a bit slower than a belt grinder, but also much cheaper.

I got most of this from the sharpening FAQ here, and it explains it a little better. It's very comprehensive and well written. Good luck with your sharpening.
 
You can sharpen a convex edge freehanded on stones, but it's a little tricky. You have to decrease and/or increase the sharpening angle in a smooth and continuous motion as you stroke the blade across the stone. It sounds more difficult than it actually is, but it does take at least a little bit of skill. Sharpening a convex edge on a stone might not be something an absolute beginner sharpener would want to try.

As the sharpening gurus have pointed out, a strop might be a better option than a stone for working a convex edge. Anything with a bit of slack in it (strop, leather on a board, sandpaper, cardboard) can curve around the convexity of the edge. A stone is less forgiving; since it's flat, there's always the possibility of accidentally creating planes on the edge instead of keeping it in a smooth curve. Something with slack in it will naturally conform to the rounded curve of a convex edge though.

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Cerulean

"My good reason to carry a knife is that God gave me rather weak teeth and rudimentary claws in an evolutionary trade-off." - J.K.M.
 
I'm afraid the only way you can put a genuine convex edge on a blade is with a slack belt on a $400.00 + belt grinder. They tell me that guys who have been doing it a long time 9(aka Bill Moran) can put such an edge on with a few swipes on each side. I have tried and it is much harder to do than it seems. I usually get one bevel much wider than the other.

There is another way. You can double bevel your blade. The only thing you need is a sharpening device that provides for multiple angles. Put your first bevel on very narrow. (16-18 deg.), then finish by increasing the angle to 20-25 degrees. What you have done is remove a large part of the shoulder where the bevel starts. So you are almost at a convex edge but not all the way there. The reason I mention such a disparity in angle choices is that there are many philosophies. Joe Talmadge and I discussed several different approaches. Find the one that work best for you. By the way, the only real advantage of the convex edge is that it eliminates some of the drag caused by the bevel shoulder. It is no sharper than your regular single bevel.
 
I'm afraid the only way you can put a genuine convex edge on a blade is with a slack belt on a $400.00 + belt grinder. They tell me that guys who have been doing it a long time 9(aka Bill Moran) can put such an edge on with a few swipes on each side. I have tried and it is much harder to do than it seems. I usually get one bevel much wider than the other.

There is another way. You can double bevel your blade. The only thing you need is a sharpening device that provides for multiple angles. Put your first bevel on very narrow. (16-18 deg.), then finish by increasing the angle to 20-25 degrees. What you have done is remove a large part of the shoulder where the bevel starts. So you are almost at a convex edge but not all the way there. The reason I mention such a disparity in angle choices is that there are many philosophies. Joe Talmadge and I discussed several different approaches. Find the one that work best for you. By the way, the only real advantage of the convex edge is that it eliminates some of the drag caused by the bevel shoulder. It is no sharper than your regular single bevel.
 
You have gotten some great advice here! Good jobbie forumites!

I have the Razor's Edge Pro kit (2" by 8" stones, folding steel, big and small knife guides, edge tester and the case) and before I started using my current sharpening methods, I was in love with that kit. The rough stones work real fast and that folding steel is the best steel out there, in my opinion. Do think of sharpening techniques and gear as a learning experience, as the techniques and gizmos change all of the time. I started with a sharpmaker, went to the Razor's Edge kit and now I use my belt sander and Sharpmaker for my sharpening needs. By the way, I am learning how to make knives, so that is why I have a belt sander! Though it was considerably less than $400. Any belt sander will do as far as I know, but power equipment is hardly portable, dangerous and if you don't get the technique right you wreck things quickly. Burnt steel sucks!!!

Ihave been mulling over the idea of selling my Razor's Edge kit, which is in good working order still! E-mail me if you want to chat more about the RES kit, or perhaps we can work out a deal.

Good luck on your search for sharpening info.

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"Come What May..."
 
You can also use a plain old bench grinder if you have one. If you don't I think they can be had for somewhere around $40.00 and up. The following is a quote from Jason Stewart, formerly of the Marbles knife co, who also use the convex grind. Hope it helps.

"Your most likely will get the best results, however, by using a stitched muslin wheel and then a loose wheel, both made of cotton.
On the stitched wheel, use a black greasy compound (about 600 grit) that you can obtain most likely from the same place you're getting your white compound. Lay the blade against the wheel at a slight angle (12 to 14 dgs.) and apply firm pressure, starting at the choil and working your way to the tip. One or two passes on each side should do it. COOL THE BLADE with water.

Now, use "knifemakers green" compound, also easily available through Koval or Brownell's, on the loose wheel. Be careful, these are grabby wheels . One or two passes on each side should work. Now you're done. By the way, you can probably substitute the white compound you have for the green."

 
All of the above posts have something in common - no matter what tools you use - you need practice. Buy a couple cheap knives from Walmart and start on them until you get the knack of your system.

Steve-O
 
Thank you all for your wonderfall advice! It will really help me in choosing the proper system/sharpener. BTW I had looked at the sharpening FAQ before but all it did was confuse me more. Looking at it again it seems to make more sense.

Steve-O thanks for your suggestion, thats exactly what I was hoping to do as soon as I find a store around me or an internet store so shipping isn't more then the knives
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that stocks a few varieties of Frost Moras.

Thanks again!
Derek
 
skarb:

<font face="Verdana, Arial" size="2">I'm afraid the only way you can put a genuine convex edge on a blade is with a slack belt on a $400.00 + belt grinder. </font>
Click to expand...

You can buy a slack belt sander for about $50 which will easily handle all such sharpening. You don't even need the sander, you can simply use the sandpaper manually as described in the above. It takes longer but the quality of the edge is the same.


-Cliff
 
You can maintain a convex edge with a flat benchstone by using trailing strokes, pulling the blade backwards, just as you do on a strop. I use this technique on my Marble's blades which came with convex edges. Takes a bit of practice, but it works great.
 
Quick question: I was looking at honing/stropping leather on Lee valley site and wasn't sure which type was necessary the link shows the strop that has leather attached to wood and looks like it would work well. But they also sell leather just as pieces and you can stick it to your own wood or use as is. Question is which is better, are pieces of leather more easily usable for strop or is one on wood?

http://www.leevalley.com/wood/page.asp?page=32971&category=1,43072&ccurrency=1&SID=

Thanks,
Derek
 
If you have a chunk of wood sitting around and don't mind doing a bit of work then buying the leather and compount is fine, as it saves you a bit of $$. If you don't feel like making a strop, buying the already made one is better. If you can find some place near you that sells buffing compound, I'd suggest also going to a leather worker and telling them that you want a strip of leather 2" by 8 or 10" to make a strop out of, and they'll sell you a piece.

Good luck strop hunting!

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"Come What May..."
 
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