KME Strop vs Lapping Films

J

Jason Puckett

Joined
Feb 14, 2019
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204
So, my poor impulse control and a really good deal led to me buying a KME system. It's the base system with the 140, etc. To start out I have no plans to majorly re-profile anything, I just want to be able to get what I have good and sharp, so I'm going to put off getting the 50 and 100 grit until I can sharpen well and consistently.

I know the 1500 grit will get me a good working edge, but if I wanted to take it further and go for a polished edge, is there much of a difference between a strop with stropping compound and the lapping films?
 
Jason Puckett said:
but if I wanted to take it further and go for a polished edge
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Stones.
~= 2,000, 4,000, 8,000
If you want to get really crazy add a 12,000 or 15,000

Maybe you don't need the 2,000 if you can get all the scratches out from your 1,500 using the 4,000

Back in the day I went from a King 1,000 or 1,200 to a Shapton Pro 2,000 to the Norton 4,000 and then Norton 8,000
Now I just use all Shapton Pros or Shapton Glass and don't skip a grit in that general range.

PS: Gritomatic's G8 8,000 stone is killer great. I was using that in my Edge Pro yesterday :thumbsup: It is a Silicon Carbide water stone. I can't say enough good about it. Stays flat, cuts hard steel, cleans up easily with a nagura. Leaves a very high polish; maybe not a super mirror but to the unaided eye . . . it's a mirror ! ! !
I think they make one for the KME
 
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Hrmm, the stones are a little more expensive, but they're also going to last a lot longer than either the stropping compound or the lapping films. I hadn't even considered higher grit stones, to be honest. Thanks.

On a more generic note, is there a practical difference between stropping and lapping?
 
You may get a better performing edge from the stones. You can go edge leading as well as edge trailing on the stones. On tapes / films some times the edge cuts into the tape when going edge leading so the stones are faster.

To me stropping is a way to remove the jagged remnants of the bur.
To me Lapping is refining and polishing the edge and the bevel to create the apex.

In other words Stropping is the final step of debruing the apex once it is fully created and most all the bur has come off on the stones.

Too much refining / polishing with strops has the potential to actually round over or otherwise make the edge less effective at cutting the firmer materials such as wood or cardboard etc.

Stropped edges that tend to suck cutting those materials can still whittle hair quite impressively.
Depends on what you are after.
 
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Jason Mr.Wizard nailed it on that short statement^. I've been using the KME for a couple months now and I just picked up the full lapping to try mirror finishing and I have had great success. You will be amazed at how precise your edges will be and it's very easy to achieve perfect mirror edges. Quick tip #1: Always start out lapping with downward strokes and only run the film a quarter of the way past the tip of the blade. Later when you feel comfortable using them you Can use a back and forth motion with little to no pressure applied but again start of with downward strokes first then back and forth motions. tip #2 to avoid contaminating your films with the corser grits I rinse the films in warm water and dish soap before I use them and I wipe the blade clean between each gritt. Honestly it's very simple to achieve a good reflective edge with very little practice.
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Thanks Night Rider Night Rider ! I remember in another post you said you did that s&w with just the 9 micron, right? I'm probably going to pick up the 9 micron, and will add the others over time.

What is the knife in your first picture? It looks like a cast iron cleaver! :D
 
Jason Puckett said:
Thanks Night Rider Night Rider ! I remember in another post you said you did that s&w with just the 9 micron, right? I'm probably going to pick up the 9 micron, and will add the others over time.

What is the knife in your first picture? It looks like a cast iron cleaver! :D
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Yes you are correct Jason. The SW and the Kershaw Blur were polished with 9 Micron film only. The Kershaw Natrix and Gerber Flatiron Cleaver had the full treatment of 9. - .10 Micron films. I think you can tell the difference of only using 9 Microns by the slightly hazy look of the last two pics but starting out with a 9 Micron film is a great way to get your feet wet so to speak and you will have great results i'm sure. So order one up (9 Micron) and be prepared to amaze yourself and have some fun at the same time.:cool::thumbsup:
 
Night Rider said:
Mr.Wizard nailed it on that short statement^.
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Thanks!

Night Rider said:
[with lapping film] it's very easy to achieve perfect mirror edges.
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When everything is working right I agree, but in off cases I feel that strops are significantly more error tolerant. For example I find that the conformity blends over these issues that lapping film may not:
  • change in thickness from one film holder or strop to the next
  • overgrinds, convexing, or faceting on the bevel left from lower grits
  • strong blade curvature (belly)
  • wavy or warped blades
  • recurves
  • plunge grind imperfections
  • jig imprecision (flex in clamp or arm; rocking on blade table; slop in pivots)
The aesthetic caveat is that if strops become contaminated you'll get random scratches, when film can simply be replaced.
 
Mr.Wizard said:
Thanks!



When everything is working right I agree, but in off cases I feel that strops are significantly more error tolerant. For example I find that the conformity blends over these issues that lapping film may not:
  • change in thickness from one film holder or strop to the next
  • overgrinds, convexing, or faceting on the bevel left from lower grits
  • strong blade curvature (belly)
  • wavy or warped blades
  • recurves
  • plunge grind imperfections
  • jig imprecision (flex in clamp or arm; rocking on blade table; slop in pivots)
The aesthetic caveat is that if strops become contaminated you'll get random scratches, when film can simply be replaced
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  1. Mr.Wizard I have a couple answers to the issues you brought up. . KME has done a wonderful job at maintaining the same thickness of their Diamond stones, wet stones, and lapping films. They have also recently released a thickness compansater for other manufacturers stones but I have not used one yet. . As for over grinds, convexing, or faceting, The beauty of a fixed system like the KME or WE is that the final lapping film you use will be gliding on the exact edge plane that the first sharpening stone created. This creates a perfect line where the plunge grind meets the edge that is aesthetically pleasing with coated blades. . For curvatures employing sweeping motion diagonal to the edge will take care of that but recurves call for the addition of a tapered 3 sided Diamond stone. . Wavy or warped blades are no good on a clamped system. . Fixing plunge grind imperfections will not work on a clamped system. . As for Jig imprecision (flex in clamp or arm; rocking on blade table; slop in pivots) The KME has only one pivot and one guide rod. The pivot is never more than 5 Inches away from the blade edge thus leaving no room for rod or guide flex and when used with the base the blade is only 6 inches off the table and very stable. . When it comes to blades flexing or wiggling in the clamp, some blades will give you a harder time than most like large swedges, fullers, Funky shapes, or distal tappers but the rubber clamping surface varies in thickness front to back and makes up for those Slightly. A couple layers of painters tape on the spine can make up the rest in most cases. I recently made up some leather strops and started working on my Technic and I was amazed at how quick I could put a working edge on my work knifes with just a couple of passes but I also took a razor sharp edge and ruined it when I tried to polish the edge so I have a lot to learn in the hand stropping department. When it comes to free hand sharpening I have Zero skills and can turn a scalpel into a butter knife real quick free hand on wet stones Lol and that's why I love the KME so much because it's like edge perfection for Dummies like myself :D.
 
I got my KME yesterday and broke it in on an old Rado cutlery kitchen knife that was basically a butter knife at that point. It took some work, since I don't have the 50 or 100 grit and was basically putting a new bevel on it, but I got it sharp. Then tonight I tried it with a Kershaw Shuffle. I spent a good hour on it with the 140 grit stone, working up a burr on one side, flipping it and working up a burr on that side as well. Then I did a few more passes on each side before moving on to the next grit, and repeated the process up to the 1500 grit (I haven't gotten my lapping films yet). I ended up with a near mirror polished dull knife. It's definitely sharper than when I started, but nowhere near shaving sharp. It won't even catch on my thumb nail.

I suspect that I didn't full apex the edge, but I thought that was what the burr meant. Any ideas as to what I'm doing wrong? I'm pretty sure my angle was right, I used the sharpie and marked the edge between each grit and it always took off all the sharpie after one or two passes of the stone.
 
The edge should catch on your thumbnail from both sides after every stone along the entire edge. If you are checking this consistently you will know where in the progression something went wrong.
 
Thanks M Mr.Wizard . I wasn't taking it out of the clamp to check after each one, because I was worried about being able to get it back in the clamp in the same position. This one is DLC coated, so I can't draw a cheater line on it in sharpie to be sure I get it right. I checked the knife again this morning and there's definitely still a burr on one side too, so when I get time tonight I'll knock that down and see if that helps.
 
You can leave it in the clamp and check the edge with something else, like the barrel of a plastic pen, if your thumbnail would be too awkward. Regarding the DLC coating, are you concerned that the marker will stain the coating? That would surprise me. Nevertheless you can use an overhead transparency marker if you want something water soluble.
 
No, just didn't think I'd be able to see black marker on a black blade. It's an old beater from my desk at work, I'm trying to practice on all my El cheapos before I use it on any of my good knives.
 
Jason Puckett said:
No, just didn't think I'd be able to see black marker on a black blade. It's an old beater from my desk at work, I'm trying to practice on all my El cheapos before I use it on any of my good knives.
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Smart move using beaters to practice on Jason, I started with a couple kitchen knives first. When sharpening be sure to raise a bur tip to base, flip, and repeat threw all of the diamond stones. keeping count of the number of stokes on each side is very important in order to keep the edge centered. On the finer stones it can be hard to detect a bur so you can lift the blade holder out of the base (keeping the blade in the clamp) and angle it downward then look at the blade from the spine side towards the edge and you will see a very thin shinny line, That is your bur. For under ten bucks you can pick up a 10 Times magnification jewelers loupe and that will make the process almost fool proof. The Loupe will come in handy when you are trying for a mirror edge by checking for scratches. You will want to make sure that you removed all the scratches from the previous stones and films as best as possible. I picked one up with a built in light source (LED) for $10 bucks on Fleabay. Last but still important, Don't bother wasting your lapping films (when you get them) unless the knife is sharp first. So tonight when you have some free time make yourself a drink and give it some more practice, you will get it. Have fun and good luck :thumbsup:
 
Thanks Night Rider Night Rider , some folks on the edge snobs FB group suggested I hadn't fully deburred either, and they were right. When I woke up this morning, I checked it and sure enough there was still a considerable burr on one side. Few quick strokes with the 1500 grit stone and it's nice and sharp now. Thanks for the tip on the loupe, I'll have to pick one of those up.
 
Glad you're getting it sorted out. Another thing to remember is go light. Diamonds require slight pressure and applying too much can bugger your edge and eventually ruin the stone. It's easy to start grinding hard without realizing it when you have been at it a while and/or start getting flustered.
 
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