Swivel knife sharpening

[Mungo]

Is it possible to change the geometry of a swivel knife blade just by stropping it? My knife came with a fantastic blade and I would hate to alter it to an undesirable angle. I probably don’t strop it as often as I should and when I do it’s only stropped two or three times on each side. Still, if need be I could get something like the Big Red by Chuck Smith to correct the angle. Thanks 

[dikman]

You'd have to do a lot of stropping with a coarse abrasive to significantly change the blade geometry! Eventually though it would need touching up on an oilstone.

Edited 6 hours ago by dikman

[bruce johnson]

My thoughts and experience.

1 - You can’t change the overall blade angle much with stropping compounds even if you use black emery. If You can do that, you have my respect for perserverence.

2. You can however round over a blade edge very easily using mild compound on a  strop and either a) - not keeping a constant angle or rolling that angle  b) keeping the angle too high or c) using a soft strop

3. Use a mild compound on a firm surface like card stock, file folder, or hard roll horsebutt for stropping a swivel knife. And don’t do it a ton. A few strokes to clean but much more than will violate point #2 above. I like purple compound but green or white is OK. Whatever you’ve got that isn’t black or red. 
 

Round and cutting knives can use a “softer” strop like vegan leather because a little convexing of the edge can make a “Moran edge” that is durable. On the other hand Swivel knives  I feel need a flat edge all the way out for easier and cleaner cutting. That means a harder strop and less aggressive compound. 

I’ve had a bunch of swivel knife blades through here in all tiers of quality and use. I probably have 75 blades right now. When I sharpen one I set the blade up in a jig and mark the facets with fluid. . I can guarantee that more than 95% of them will not scratch the marking fluid off the very edge intially because the edges have been rounded from in inconsistent angle on an abrasive maybe but mostly due to over stropping.

I go back up the grits to something coarser to flatten the facets and bring back the angle and then run through my grits to 5000. Then I strop with the jig at 1 to 1.5 degrees higher with purple compound to take off the burr edge. It’s literally almost just a touch on each side for the bur.
By hand, there are a few jigs I like and the Big Red you mentioned is sure one of them. I think hitting a blade on 2000 if needed and then 5000 wet/dry with a jig and a light strop as above to maintain is better to maintain than stropping the crap out of them like has been recommended by a lot of people the last 50 years. 
My thoughts for what it’s worth. 

[Mungo]

Thanks for the replies, I think I’ll go ahead and get that Big Red just in case. Never underestimate my ability to break things.