I think I am through with diamonds!

Sharpnessis

Sharpnessis

Joined
Aug 11, 2012
Messages
810
I have tried hand stropping and then power stropping. NO matter what I do I seem to make the edge more dull. With 0.5 diamond spray.

I've tried different angles. More on the shoulder then more on the edge. To no avail! I think I'll stick with tried and true. For me that is.

Is there a secret? If I can get an edge screaming after green compound, I thought diamonds would make it even keener. More "toothy", I was hoping. Sometimes the edge feels a little sticky though.

Any secret tips from the pros would be most appreciated.

Thanks

-David
 
I'm about 99% sure it's either too much pressure on the strop, or just over-stropping, or both. I went through the same thing when getting acquainted with stropping in general. Diamond compound is pretty aggressive, even at small grit, and it's easy to overdo it. Some compounds cut the steel much more quickly, and over-stropping will almost always take the edge past the point of diminishing returns, especially if the backing is softish (leather) and too much pressure is used. It happens even faster on softer or less wear-resistant steels, which shouldn't take many passes on diamond to make 'em sing. On that note, what steel are you stropping?


David
 
The difference between .5 Micron compound and .5 Micron compound is very small.
 
Without watching technique, it would be tough to be sure.

Pressure (avoiding too much) is ever bit as important as correct angle. Also, while keeping the angle of stropping constant, you need to pay particular attention to the end of the stroke. There is a natural tendency to roll the edge to a higher angle as you finish, as if you were sweeping the floor. Pay special attention to the end of the stroke. It is most important. That last 1% will undue the rest of the stroke on the strop.
 
If you are ready to use .5 micron compound, you shouldn't be needing more than 8-12 strokes per side. I have a feeling that you may be 'over-stropping.'


Stitchawl
 
Sharpnessis said:
I may be overdoing it. Thanks. I will try again. I'm really hoping for that toothy effect.
Click to expand...

It's very unlikely you'll create much toothy effect from 0.5 micron diamond compound on a strop. It's more likely to highly polish and diminish whatever teeth are there. A 'toothy' edge is first dependent on what's done on the stones; most of the 'bite' is created there, and stropping on leather or any other softish backing, with fine compound, generally will only tend to refine it (make it less so). If you want to maintain some 'teeth' in the edge, finishing on the stones at a somewhat coarser grit will make most of the difference, and then some light stropping afterwards, to clean up the burrs, will get most of it done.


David
 
THANK YOU Obsessed!

I have been struggling w/ this dull ass Bark River I bought a while ago, came dull. Also my first convex edge. I watched all the videos on the tube, crazy virtuavoice include. Everything made sense to me, just couldn't establish an edge, and keep it, going from 400/800/1000/1500/2000/ black compound strop/ green compound strop.

I figured out I needed a lower grit to build a wire edge first, I started with 320 grit/ went to 800- then a few strokes black compound/ a few green compound, and can still cut paper that I could cut at 320. I think I figured this convex thing out, at least a little bit. I was using a semi-flexible piece of foam backing.
 
The reason I thought I would get a toothy edge is because of jdavis882. He showed how this 0.5 micron would do that. Damn YouTube! :confused:
 
Hey David. I use a belt sander. If I went to 320 grit then straight to the leather belt with green compound would that give me more tooth but still remove the burr? I've been wondering if a paper wheel would be better than the leather, as far as leaving it more toothy, and burr removal?
 
Can't speak to your situation, but I have used a belt sander to try to touch up an edge, and f_cked it up royally. You might be better served trying it manually, with a mouse pad/foam/ and sandpaper, that way, you have more room for error, or get some dull cheap knives to practice with on the belt sander first.
 
I'm pretty sufficient with the belt sander. I can get an edge screaming sharp, however, the edge feels like a piece of glass at the edge. When I run my fingers down the edge it doesn't want to cut. It is sharp, I'm not pressing hard, but I want to to be scared of the darn thing! Lol! I hope what I'm describing is possible? Maybe I should send a knife to Richardj and see what's possible?
 
If you send it to Richard J. it will give you a benchmark to strive for. You won't regret it.

Blessings,

Omar
 
Sharpnessis said:
Hey David. I use a belt sander. If I went to 320 grit then straight to the leather belt with green compound would that give me more tooth but still remove the burr? I've been wondering if a paper wheel would be better than the leather, as far as leaving it more toothy, and burr removal?
Click to expand...

IF (and only if) you're very comfortable with using the belt sander on your knives, that'd be one way to do it. Otherwise I'd avoid that. I don't have or use one myself. One very quick method I often use, to add some quick teeth to an edge, is just to make a handful of stropping passes (maybe 5 or less per side) on some medium-grit wet/dry sandpaper. In fact, lately I've been re-tuning the edges on several blades doing just that. I prefer very firm/hard backing under the sandpaper (I use glass), and it's been working well. Anything between 400-800 grit usually does well, and even 320 works pretty nicely (don't get too carried away with this grit). Following with green compound on a strop or belt might work as well, to clean up any burrs.

I asked earlier, what steel are you sharpening? I've liked green compound on 1095 carbon blades, and it also works well with simpler stainless steels as well, such as 420HC/440A and similar steels.


David
 
Sharpnessis said:
The reason I thought I would get a toothy edge is because of jdavis882. He showed how this 0.5 micron would do that. Damn YouTube! :confused:
Click to expand...

Way too many variables to predict how the compound by itself will affect the finished edge. With compound that fine, the condition of the edge before stropping will make the most difference. The stropping material and backing underneath it (wood, glass, etc.) will affect how aggressively (or not) the compound works. Steel type makes a BIG difference, vs. what compounds are used. And as has been mentioned, going just a little too far with the stropping can quickly negate any positive results. A lot of 'skill' in sharpening and stropping often comes down to knowing just how far to go, without overdoing it, and knowing when to stop.


David
 
Thank you David. I have been sharpening mainly vg10 and my new case cv blades (think they are 1095). I realize the vg10 is much harder. Either way I was hoping I could get a mirror polish, which I did get, I sharpend to 3000 grit, then stropped from course to xfine using all 4 strop man compound. The blade was sharp! I could slice phone book paper easily, no problem. So I used the half micron diamond spray on buffalo leather. Can't tell a difference. Was really hoping for those teeth. Thought it was the best of both world's. Mirror polish AND teeth.
 
Sharpnessis said:
Thank you David. I have been sharpening mainly vg10 and my new case cv blades (think they are 1095). I realize the vg10 is much harder. Either way I was hoping I could get a mirror polish, which I did get, I sharpend to 3000 grit, then stropped from course to xfine using all 4 strop man compound. The blade was sharp! I could slice phone book paper easily, no problem. So I used the half micron diamond spray on buffalo leather. Can't tell a difference. Was really hoping for those teeth. Thought it was the best of both world's. Mirror polish AND teeth.
Click to expand...

Try stropping on a very firm/hard backing (like glass or hardwood) using compound on a thickness or two of paper, or on very thin cardboard (kleenex box, food packaging, etc.), or on the wood itself. Unless technique is perfect (angle control, proper use of pressure), stropping on leather or other more forgiving (softish) substrates is always going to be prone to some apex rounding and polishing, due to the way the substrate rolls around the apex under some pressure. Used with compound, that effect is magnified further, and it gets worse if the edge is over-stropped. The goal is to polish the bevels only, without taking much away from the edge apex itself. If you use your stones or sandpaper/belt grinder or whatever to create the 'teeth' in the first place, you want to minimize what stropping takes away from that. Using a firm/hard backing to polish the bevels only, while just barely 'kissing' the edge apex, is what will help protect the bite in the edge. I've been tending to favor stropping by these methods (paper/cardboard with compound, over glass) mainly for this reason. My finished edges are retaining more of the 'bite' this way, because the apex is now crisper than I was getting on leather before.


David
 
Wow! Thank you for the time out of your day to help me.

This makes sense and I will try it right away! A little nervous about just kissing the edge. I will need my 30x loupe for this job!

:beer: cheers to you my friend!
 
Sharpnessis said:
I have tried hand stropping and then power stropping. NO matter what I do I seem to make the edge more dull. With 0.5 diamond spray.

I've tried different angles. More on the shoulder then more on the edge. To no avail! I think I'll stick with tried and true. For me that is.

Is there a secret? If I can get an edge screaming after green compound, I thought diamonds would make it even keener. More "toothy", I was hoping. Sometimes the edge feels a little sticky though.

Any secret tips from the pros would be most appreciated.

Thanks

-David
Click to expand...

As already mentioned a number of times, it is very difficult to put "tooth" back into an edge by stropping. Generally you'd have to drop back down to a larger grit - something in the 10-20 micron range. By using an extremely firm backing you can minimize the smoothing effect of compounds, but if you apply it to anything with even marginal give the abrasives will all sink into the material, you'll get fairly even pressure and use only a fraction of the abrasive surface. A .5 micron abrasive might only have half of that standing proud enough to bite on steel - it'll polish off your teeth if you apply more than a handful of very light passes. As your backing material gets harder, you'll find yourself in a different sort of operation - materials that have less give also have less for the abrasive to catch on and you'll be doing more lapping than polishing. You can apply compound to wood, but the vehicle the abrasive is suspended in and how it reacts to the surface (wood, glass, etc) becomes more and more critical. The abrasive might slide across the surface or roll. This is why, depending on the edge you're looking for, you might want to use a larger stropping abrasive like black emery, takes a lot of guesswork out of the situation.
Polishing (stropping) a relatively toothy edge with a really fine compound, as you describe from your belt sander, frequently leaves a smooth but overly broad cutting edge. The belt leaves too many irregularities and the compound concentrates pressure at the apex. The apex width is a function of the size of your grinding abrasive. Polishing a sharp but irregular 320 grit edge to a mirror, will leave you with an apex that is somewhat more obtuse than you realize. Paper wheels would minimize this I believe, as the wheels are very dense and will not conform around the apex any where near as much - the pressure doesn't concentrate at the point where the belt comes off the apex. The other way around this is to move to a much more acute edge and belt polish at a more acute edge too. In any event, stropping with a powered belt and fine abrasive is going to remove some tooth no matter how careful you are. If you're using waterstones, you could try backhoning right on your 3000 grit stone, strop on some plain paper or newspaper and you'll have very sharp but catchy edge.
As mentioned, much easier to preserve tooth than it is to put it back. And of course, different grinding and finishing methods all produce slightly different types of edges...
 
sharpnessis, send me the knife you are having problems with so i can see it. then i'll sharpen it up so you can see the difference. just pay return shipping and insurance. send me an email and i'll send you my info.
 
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