power stropping questions

O

oldskywalker

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Sep 18, 2021
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Hello to everyone. I wanted to get into sharpening my own knives and bought a 1x30 Fucina belt sander, variable speed. I'll be sharpening mostly kitchen, fillet and hunting knives for everyday use. I just want to be able to put on a good working mans edge (a little toothy) and not necessarily looking to whittle hairs.

I'm having one problem. The stropping part is taking way too long. I've been starting with a 220 grit and following with a 400. Then I go to leather strop. At this point it takes forever to remove the rolled over burr. Probably about 20-30 passes. I check it with a 50x scope as I go along and while it feels fairly sharp I can still see the burr side rolled over (on the same side, I'm not making a new burr). I first tried with white compound and then also tried 6 micron diamond (gunny juice). The diamond actually cuts slower!... slower, but ends up sharp. Maybe I just need more on the strop but I thought I put on plenty.

I have a feeling the answers are going to be I need to progress more before stropping... maybe a 1000 grit. The thing is the belts wear really fast and don't want to have to replace a belt every two knives. So would a solution be to maybe strop with a 15 micron (or coarser) leather belt and then progress one more time to a 6 micron or less?

I don't understand how so many people stop at 400 grit and then claim to hit it a few times with green compound and it's done. I also have some .5 micron diamond coming but I'm waiting for my new leather. I had a thought that maybe finer diamond could remove the burr faster? Any thoughts or suggestions would be greatly appreciated. Thanks.
 
Perhaps its down to the belt sander method itself, but more than likely due to the lack of grit progression in combination with the amount of force you're using.

Try pulling the burred edge through a piece of scrap wood a few times before stropping.
 
SwissHeritageCo said:
in combination with the amount of force you're using.
Try pulling the burred edge through a piece of scrap wood a few times before stropping
Click to expand...
If that's the case maybe I need to simply progress one more time just to straighten the burr. I could be I'm using too much pressure and rolling the burr over (and it is rolling over as I can see it on the 50x scope. I'll keep trying different things until I get it. Now I understand why everyone says it takes time and practice.
 
Powered grinding can easily leave burrs that are much thicker & stronger than burrs created on stones (usually). Such heavy burrs won't be removed on a simple leather strop. Finesse and a very light touch are needed to reduce & thin the burr on the belt first, so the burr is light & thin enough to be easily cleaned up on the strop.

Reduce the pressure used on the finishing belt as much as possible, to reduce the burr. If the burr is still too tough to remove on the strop, that's the cue that further refinement (burr reduction) is necessary on the belt. OR, follow the belt with a few very light passes on a stone of similar or higher (finer) grit, to reduce the burr before stropping.
 
Are you doing edge leading grinding? That might cause this roll-over you describe.
On the belt grinder, I sharpen edge trailing, at the slowest possible speed, use very little down force, and progress to at least a 1k before moving to leather with Cr02.
After that, I usually do about 10 passes, each side, on an unloaded hanging leather strop.

-Phil
 
Obsessed with Edges said:
Finesse and a very light touch are needed to reduce & thin the burr on the belt first, so the burr is light & thin enough to be easily cleaned up on the strop.

Reduce the pressure used on the finishing belt as much as possible, to reduce the burr. If the burr is still too tough to remove on the strop, that's the cue that further refinement (burr reduction) is necessary on the belt. OR, follow the belt with a few very light passes on a stone of similar or higher (finer) grit, to reduce the burr before stropping.
Click to expand...
Got it. Makes perfect sense. I'll try that.
 
pwest said:
Are you doing edge leading grinding? That might cause this roll-over you describe.
On the belt grinder, I sharpen edge trailing, at the slowest possible speed, use very little down force, and progress to at least a 1k before moving to leather with Cr02.
After that, I usually do about 10 passes, each side, on an unloaded hanging leather strop.
Click to expand...
I sharpen edge trailing. I think I might be pressing too hard. I'm going to try to be extremely gentle and see what result I get.
 
O.K. problem solved. I just finished sharpening an edge and it turned out awesome. I slowed down the sander (very slow) and used light pressure (light as a feather) with the 400 grit so I wouldn't roll the burr over. Basically tried to polish and finish it with the 400 grit. Then hit it with a few passes on the strop and it was done. Looked perfect under the scope too. Sliced paper very smooth.
 
Last edited:
Not mentioned yet, but perhaps useful-
Different steels have different burr characteristics generally. Then heat treat, and geometry add two variable effecting burr character. You might add dedicated note book to log observable characteristics with your 50x scope and edge performance with your uses.
 
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