Help getting that last bit of sharpness

confucius37

confucius37

Joined
May 18, 2008
Messages
1,168
I have been working on my routine with a DMT aligner kit. I have been working at it for about 3-4 months now and I have it down to a point where I can get an edge to easily shave hair and 90% of the time whittle hair with some effort and it's a short whittle, meaning it doesn't slice into the hair for very long, its more like it just catches and splits the hair, but doesn't really whittle it.

I understand that hair whittling isn't necessarily an indicator of long term edge performance or even real world application, but I am just curious and have a desire to get a very refined hair whittling edge.

Typically my routine is as follows:
I use all DMT stones. I make sure that the knife is securely clamped and does not move. I use light pressure and decrease pressure as I go up in grits.

XC: get a burr on one side and flip to the other side. Reduce burr until not very noticeable with hand
C: get a burr on one side and flip to the other side. Reduce burr until not very noticeable with hand
F: get a burr on one side and flip to the other side. Reduce burr until not very noticeable with hand
EF: get a burr on one side and flip to the other side. Continue with this stone alternating sides reducing the number of strokes per side from 5 to 1 stroke per side and alternating each stroke in order to get the most minimal burr. For the last step I use only edge leading strokes to try to minimize burr formation.
EEF: get a burr on one side and flip to the other side (it's usually hard to detect the burr at all, sometimes I use a 30x loupe to check the edge for a burr). Continue with this stone alternating sides reducing the number of strokes per side from 5 to 1 stroke per side and alternating each stroke in order to get the most minimal burr. For the last step I use only edge leading strokes to try to minimize burr formation. I finish with 10 alternating stroke (1 per side) with most minimal pressure while still maintaining positive contact with the edge.

For the entire duration I use the clamp, I am careful to make all the strokes a consistent angle.

Strop: Finally I strop 20 strokes per side using green compound applied to a flesh (suede) side piece of tooling leather with a hard wooden backing. I use a VERY low angle, likely not making full contact with the apex at each stroke. I try to maintain very light pressure, as light as possible. I use such a low angle because if I start increasing the angle then I notice degradation in the edge compared to no stropping at all. I finish with a final 10 strokes per side on bare leather skin (smooth) side up.

I most recently used this method on a small Buck Vantage Pro (S30V). I use the lowest angle setting and I use a zip tie spacer. The resulting edge angle is between 32-34 degrees inclusive (based on DMT's FAQ on aligner angle settings).

With the above method I was able to achieve an edge on the Buck that shaved well and would whittle hair inconsistently (as described above). I notice that the edge does last a decent amount of time, I am just curious, what do I need to do to achieve a true hair whittling edge (even if it degrades very rapidly after initial sharpening). Or is just a matter of more practice and more patience?
 
dull your knife a little and it will whittle ;), splitting is a bit sharper than whittling, unless your hair responds different to mine
 
Grind equally. Grinding on one side until a burr forms means the edge has lost all symmetry.

Changing the strop leather type will help too, its not suitable for its current use. Also note that chromium oxide will be extremely slow on S30V. Slow like its almost not working.
 
I find that I tend to start sharpening on one particular side. If I always raised a burr before I switched sides, instead of sharpening equally on both sides, I'd end up with an uneven edge. Am I the only one who always starts sharpening on the same side?
 
My thoughts on your process...

Edge leading strokes only on the DMTs, no trailing strokes, equal strokes per side,

Stropping is the only place I would use edge trailing strokes, its what stropping means.

Use a firmer strop, especially NOT suede side leather, the strands/fibres are going to be trying to remove the edge you've made. This is against everything you're trying to do. Try wood, or MDF with compound. This will give a nice firm edge with much less chance of rounding your edge, and are easier to use to boot, as you are less likely to ruin your work with overpressure.
 
Thanks for the comments everyone. I had a feeling my strop was too soft, I will look for something like balsa or MDF. I will also get the 1 micron dia paste to get faster cutting on my strop. Any recommendations on the "best" stropping medium to use with the dia paste?

knifenut1013 said:
Grind equally. Grinding on one side until a burr forms means the edge has lost all symmetry.
Click to expand...

I think you may be right with this one. I measured the bevel with a digital caliper and I am getting 0.79mm on one side and 0.60mm on the other (its a hollow grind so its a pretty small bevel).

My next question is then, if I grind equally, should I still be striving to raise a burr? I assume by grinding equally I will be changing sides fairly often until enough metal is removed and by the time I reach apex I should be able to raise a burr in just a few strokes on the coarsest stone.
 
Typically your should make a dozen passes and switch and repeat. If you keep alternating then technically you can form a perfect edge without ever creating a burr. But, yes, you will still be looking for that burr, just look closer and find it when the bevel planes contact.

For me I check for a burr to let me know when I'm close. I say close because the burr can trick you and make you believe the edge has reached a apex. The edge will have a very specific feel when it is finished properly on a stone. This feel is the same with all edge angles and sharpening media.
 
Ok I see, I assume you are referring to the difference between an edge that has just been folded over and not apexed vs an edge that has a true apex and is forming a burr?

Can you describe what a real apexed edge feels like? I am not sure if I have seen/felt one.
 
confucius37 said:
I have been working on my routine with a DMT aligner kit. I have been working at it for about 3-4 months now and I have it down to a point where I can get an edge to easily shave hair and 90% of the time whittle hair with some effort and it's a short whittle, meaning it doesn't slice into the hair for very long, its more like it just catches and splits the hair, but doesn't really whittle it.

I understand that hair whittling isn't necessarily an indicator of long term edge performance or even real world application, but I am just curious and have a desire to get a very refined hair whittling edge.

Typically my routine is as follows:
I use all DMT stones. I make sure that the knife is securely clamped and does not move. I use light pressure and decrease pressure as I go up in grits.

XC: get a burr on one side and flip to the other side. Reduce burr until not very noticeable with hand
C: get a burr on one side and flip to the other side. Reduce burr until not very noticeable with hand
F: get a burr on one side and flip to the other side. Reduce burr until not very noticeable with hand
EF: get a burr on one side and flip to the other side. Continue with this stone alternating sides reducing the number of strokes per side from 5 to 1 stroke per side and alternating each stroke in order to get the most minimal burr. For the last step I use only edge leading strokes to try to minimize burr formation.
EEF: get a burr on one side and flip to the other side (it's usually hard to detect the burr at all, sometimes I use a 30x loupe to check the edge for a burr). Continue with this stone alternating sides reducing the number of strokes per side from 5 to 1 stroke per side and alternating each stroke in order to get the most minimal burr. For the last step I use only edge leading strokes to try to minimize burr formation. I finish with 10 alternating stroke (1 per side) with most minimal pressure while still maintaining positive contact with the edge.

For the entire duration I use the clamp, I am careful to make all the strokes a consistent angle.

Strop: Finally I strop 20 strokes per side using green compound applied to a flesh (suede) side piece of tooling leather with a hard wooden backing. I use a VERY low angle, likely not making full contact with the apex at each stroke. I try to maintain very light pressure, as light as possible. I use such a low angle because if I start increasing the angle then I notice degradation in the edge compared to no stropping at all. I finish with a final 10 strokes per side on bare leather skin (smooth) side up.

I most recently used this method on a small Buck Vantage Pro (S30V). I use the lowest angle setting and I use a zip tie spacer. The resulting edge angle is between 32-34 degrees inclusive (based on DMT's FAQ on aligner angle settings).

With the above method I was able to achieve an edge on the Buck that shaved well and would whittle hair inconsistently (as described above). I notice that the edge does last a decent amount of time, I am just curious, what do I need to do to achieve a true hair whittling edge (even if it degrades very rapidly after initial sharpening). Or is just a matter of more practice and more patience?
Click to expand...

I use a DMT and want to know what you mean by "zip tie spacer". Thanks.
 
well, I think it was the strop that was killing the edge. I took a paint stir stick and sanded it smooth with some 220 grit and then applied some green compound with a bit of mineral oil to spread it out and let it dry overnight. This morning I took the Buck and did a quick 15 swipes per side just before heading to work. It's seriously making hair FLY off my arm now, I mean literally, its flying off. It is whittling hair more consistently now, still not exactly where I want it, but I will try again with a knife that's fresh off the stones and use the DMT dia-paste that is coming in the mail.
 
Stropping on different materials with and without compounds and abrasives is an entire science by itself. It will test your sanity...
 
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