Precise Angle with the KME?

N

No1up

Joined
Feb 27, 2016
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So I was playing around with my KME and new roo strops.

I noticed that I could no get the edge shiny through out the entire lenght of the spyderco PM2. So I placed the angle cube centered right above the edge of the blade (on the holder). And moved the holder back and forth slowly. The angle continues to change. Tip 20° and heel 18.50° . Taking a closers look at the scratch pattern it's very noticeable.

I'm wondering if I'm doing something wrong or that's just the way it is? Does the Wicked Edge have this same quirk?
 
It could be the factory grind too. A high powered 2x72 and a second longer on one spot vs the other can make this .is it a consistent problem or just the one knife?
 
I can put any knife in the clamp, set the arm and angle cube up. Set it example 20. Now if I just slowly move the arm up and down the travel path the angle will change. Higher at the tip, the angle I set it at in the middle and like 2 degrees less at the back of the blade.

I set the blade as centered and straight as I could... I'd like to have a 22.50 angle through the the blade if possible.
 
It also matters where you clamp the blade, you have to play with the position in order to get a consistent angle over the entire length of the blade. The center of the blade is rarely the "sweet spot" for getting the bevil even:)
 
It is possible that you press to hard on the sharpener during sharpening. There is a little flex in the guide rod - and that flex will give you a convex edge in about 1-1,5 degrees.

Try to sharpen the same knife again, now with very light pressure on the sharpener. It takes a little more time to do - but the scratchmarks will be veey small and innthe end you will get a veey shiny edge without scratchmarks.

Scratchmarks comes mostly from the first course sharpener you use, and to hard pressure. Next finer sharpener can not grind those scratchmarks away - if you dont let it take a lot of time to grind them away. The third sharpener with even finer grit makes the scratchmarks dissapear (for a while) - but when you start ro polish the edge - the scratchmarks are visble again...

Thomas
 
No1up said:
So I was playing around with my KME and new roo strops.

I noticed that I could no get the edge shiny through out the entire lenght of the spyderco PM2. So I placed the angle cube centered right above the edge of the blade (on the holder). And moved the holder back and forth slowly. The angle continues to change. Tip 20° and heel 18.50° . Taking a closers look at the scratch pattern it's very noticeable.

I'm wondering if I'm doing something wrong or that's just the way it is? Does the Wicked Edge have this same quirk?
Click to expand...

Try this thread... Angles on Clamp Style Devices
 
Another thing is distal tapers , clamps will give a wider bevel on a thicker part of the blade vs a smaller on a thinner .

You can sharpie in where the angles are different and sharpen then change your angle on the machine and do the other part or what I would do is just do the whole blade at the lowest angle read .
 
To get the same angle all along the edge can be a little tricky :). A tappered blade can be grinded a little diagonal where the thickest part are a little more away from the pivot point then the thinner part of the blade are. That compensate the tappering.

This link is to my homepage and my sharpening tool IcePal that sharpens ice drills. Look at the edge on the drill bit, it is one of the hardest edges in the world to sharpen, perhaps the hardest. A knife edge have 1 dimension. Drill bits on ice drills have 3 dimensions. IcePal sharpens all the three dimensions at the same time.

1 the edge angle angle holds 40 degree in one end and 20 degrees on the other end, the anhle changes 20 degrees along the edge (that is why the edge are clamped diagonal so thatvthe closets part of the edge gets 40 degree angle - and the far away part get 20 degree edge).

2, the edge is also screwed.

3, the edge are not straight, it is U-shaped.

My point here is that it is possible to adjust how the blade are fixed in the clamp and use different distances to compensate for example tappered blades.

Thomas
 
I cannot find it now, but somewhere someone posted a picture of a shoebox laid sideways with three pieces of jute looking string. All three strings were taped at the same origin, at the top far corner of the shoebox and ran down lengthwise to three different terminal points, where they were taped down, one terminating nearest, one terminating in the middle, and one terminating at the far end of the bottom of the shoebox nearest the camera. That picture provides a great aha moment as a static example, for folks not familiar with the more complex calculus of guided knife sharpening systems.
Now I see Ron has a stone thickness compensator and curved stone holder for the KME. interesting progression for compensating stone thickness and bevel radius! As I play with the KME to gain experience and understanding, I am thinking of ways to fabricate a distance measuring rod ala wicked edge for the KME.
 
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Gonna add too some clamps have issue with FFGS. I would test more knives mainly ones you've sharpened the most and with different grinds , just to rule out the machine or mind the problem ,playing with the position of the blade in the clamp may help as well , it could be a few things from loose tolerances in the machine to the grind and the way the clamp holds it ,to the person sharpening it ground an uneven bevel etc. Personally and this is just a suggestion id try to rule out if it was the machine first or a tolerance issue if no play in the arm or arm holder than look at how other knives especially knives with good flats behave as well as different positions in the clamp lastly if it's a factory sharpening goof up you just take the bevel down the lowest angle of your reading or to say 15dps to even it up.

Curious as to what the fix is , keeps us posted.
 
scottc3 said:
I cannot find it now, but somewhere someone posted a picture of a shoebox laid sideways with three pieces of jute looking string. All three strings were taped at the same origin, at the top far corner of the shoebox and ran down lengthwise to three different terminal points, where they were taped down, one terminating nearest, one terminating in the middle, and one terminating at the far end of the bottom of the shoebox nearest the camera. That picture provides a great aha moment as a static example, for folks not familiar with the more complex calculus of guided knife sharpening systems.
Click to expand...

That's an 'oldie' but goodie from Twindog...

http://www.bladeforums.com/forums/showthread.php/788007-Wicked-Edge-Edge-Pro?p=8885882#post8885882
 
Well I tried a different knife (beater knife) and th bevel looks nice like glass. So the look is uniform... But still following the path of travel with the angle cube shows the angle constantly changing... I'll have a read throw guy that thread tonight after work. I'd love some clarity. I'm enjoying learning and experimenting with different stones...

Would you guys suggest lapping film or chosera stone set as my next toy?
 
Thank you for the link to Twindog's picture. ..doh, my description was back *&#ward and upside down :-) saved as a PDF.
 
No1up said:
So the look is uniform... But still following the path of travel with the angle cube shows the angle constantly changing...
Click to expand...

Are you sure it is not just an erratic reading on the angle cube? When you move the pivot arm sideways, do you rotate the angle cube on top of the stone holder so it stays at a a 90 degree angle to to edge?

22642968589_a4d38c9c31_c.jpg


22616845288_c724f3d141_c.jpg
 
Yes and I let it settle. I'll play with it some more after work, I'll see if I can get some pictures.
 
Would you guys suggest lapping film or chosera stone set as my next toy?[/QUOTE]

I haven't taken the plunge for the Chosera stones yet. But I have the strop and lapping film sets. Working them together are great for that true mirror finish. With the great results I get I haven't found the need to get the Chosera stones.
c56fe60fb192cf8d24005291afaaf10c.jpg
 
You know what, thinking about it now. I've kept the cube parallel with the stone holder... It was like 3am so I wasn't thinking straight... I'll try again when I get home.
 
Any good way of keeping th diamond stones from scratching up the blad? I've been trying to break them in but they still scratch th blade of my heater knifes pretty good...
 
No1up said:
Any good way of keeping th diamond stones from scratching up the blad? I've been trying to break them in but they still scratch th blade of my heater knifes pretty good...
Click to expand...

Painters tape. Or masking tape . When diamonds are new hell you know what I'm about to type . If you have any old tools lying around you don't mind using grab them and sharpen them on your plates freehand use as much of the stone as you can and it will calm them down a bit .

Some diamonds break it faster than others though for instance I have a dMt ee that's 4 years old and just now am.I getting the results that are advertised with it but now that I am man oh man what a stone .
 
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