Conves Sharpening - Is Stropping on Leather Necessary?

D

Dieselashi

Joined
Feb 12, 2010
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Hello everyone,

I can't believe it's been over 3 months since I bought my Fallkniven S1 and still haven't gotten around to setting up a usable sharpening toolkit for my only convex-ground knife.

I've been tinkering with a portable convex sharpener as detailed here <http://www.bushcraftusa.com/forum/showthread.php?t=5006 >, which I suspect many of you are aware of already, and was wondering if I even need a compound-loaded or bare leather strop to finish sharpening my S1. Lee Valley has some 3M "microabrasives" listed at a .5 microns -- more or less equivalent to the ubiquitous green stropping compound -- but a sheet of the .5 micron sandpaper costs about 1/5 as much as the compound, AND I wouldn't need to buy any leather, as I don't have any properly-sized scraps laying around and I need my belt to hold up my pants :rolleyes:


One of the benefits of this sharpener is that it will cost me next to nothing and I can slap it together in my garage in about 5 minutes. Can I just go from, say, 5 micron to 1 micron to .5 micron paper and skip the leather, or does compound-loaded cowhide do something special that the sandpaper can't?

Thanks for your input!
 
The lapping film or whatever you want to call it works more than fine. Leather tends to have more drag which is good for grabbing and removing burrs, but the lapping film does awesome on its own for great edges.
 
I'm not sure I understand?
Are you skipping the leather entirely? I was under the impression that the leather also
acts as a cushion for convex edges to conform to.
I just this week tried my hand at compounds and leather stropping and have been
very happy with the results. The edge went from sharp to really sharp quite well.
 
Thanks for your comments,

Yes I am planning on skipping the leather entirely, mostly because I don't have any and don't know where to buy just the little 2" x 5" piece I need to make this strop. I was just going to use a small section of mousepad beneath the sandpaper for cushioning.

General consensus is that this will all work just fine without leather, but might be even better with leather? The reason being that even though the green compound and .5 micron sandpaper have technically the same grain size, the roughness of the leather will help grab and snap off any wire edge better than the sandpaper? Am I understanding you all correctly?

Pardon my ignorance, all I've ever used up to this point has been a SharpMaker and a little DMT stone, convex edges are a new thing for me.
Anyone have a source for small bits of leather that won't cost more to ship than to buy?
 
There are leather shops and shoe repairs in many parts of the planet - any of those should be able to sell you a scrap of leather or you could order online from Tandy or get li'l leather strop pieces pre-selected and pre-cut from Lee Valley. But leather's not particularly needed.

Neither's the 0.5 micron lapping for that matter. If you already have the compound, you rub on paper, wood, or fiberboard. If you have neither, you can pick 2,500 grit wet/dry from an autoparts store. Sure, it's 1 micron, but it breaks down faster in use to be even finer.
 
Whether leather is actually 'necessary' is a matter of personal preference. It's at it's best when refining an already very sharp edge, helps to take it up another notch. And one very nice thing about it, you can apply a wide range of compounds to it, again according to preference. I'm finding it very handy in that regard. For convex edges in particular, it's perfect, either by itself (with or without compound), or as a softish backing for convexing with sandpaper.

As for finding 'inexpensive' leather, look at it in terms of long-term cost. When used with compound, a piece of leather can be cleaned up, sanded if one wishes to do so, and will last a very long time. Without compound, if appropriate care is taken when cleaning it, it also will last almost indefinitely.

I picked up a section of veg-tanned leather at a Tandy Leather shop a while back. It's about 5.5 square feet of 7 or 8 oz. weight (just under 1/8" thickness). I cost me about $17.00. That much leather will last me a VERY long time, assuming I don't use it for anything but strops.
 
it's up to you, but sandpaper grit wears out quite fast. Check compounds online, and a bit of leather shouldn't be hard to find. But yes, sandpaper works just fine.
 
I've been noticing that the fine grit wet/dry sandpaper, such as the 3M or Norton brands, lasts a lot longer than most give it credit for (including myself, before I tried it). I've only used two pieces (about 2.5" x 9") over the last year or so, in 1000/2000 grit. That's basically half a buck's worth of sandpaper (costs about $1.00 for a sheet). The coarser stuff will lose it's aggressiveness fairly fast, but the upside is, you don't need it anywhere near as often (for heavy reprofiling jobs). In the very fine grits used in lieu of a leather strop, the silicon carbide wet/dry paper will actually get better with some use. Silicon carbide is known to 'fracture' into smaller, but still very sharp, cutting fragments, producing a finer polish. If/when it seems to be losing some aggressiveness, that's often due to it getting loaded up with swarf. That can be improved significantly by simply rinsing it off.
 
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Obsessed with Edges said:
I've been noticing that the fine grit wet/dry sandpaper, such as the 3M or Norton brands, lasts a lot longer than most give it credit for (including myself, before I tried it). I've only used two pieces (about 2.5" x 9") over the last year or so, in 1000/2000 grit. That's basically half a buck's worth of sandpaper (costs about $1.00 for a sheet). The coarser stuff will lose it's aggressiveness fairly fast, but the upside is, you don't need it anywhere near as often (for heavy reprofiling jobs). In the very fine grits used in lieu of a leather strop, the silicon carbide wet/dry paper will actually get better with some use. Silicon carbide is known to 'fracture' into smaller, but still very sharp, cutting fragments, producing a finer polish. If/when it seems to be losing some aggressiveness, that's often due to it getting loaded up with swarf. That can be improved significantly by simply rinsing it off.
Click to expand...

I haven't had to replace any of my sandpaper yet, and I've converted a number of knives over to convex. I also whipped up a few jumbo sized bench stones using SIC belts for a 3x21 belt sander glued to some brass plates. I've re beveled a number of machete's on these "stones" w/ no loss of grinding potential. Like OwE says, just keep it clean.

To the OP, it's my belief that stropping of any kind becomes less important when you're using lapping film or any other grinding media below the 1 micron range. It doesn't hurt, but unless you're shaving with it you won't notice a difference.

HH
 
If coarse sharpening is on one end and doing a shaving edge on the other end of the sharpening spectrum. Then when setting up either of these edges a correctly loaded strop is needed more. Keeping your sharpening somewhere in the middle, 400g to 800g with good stone technique most of the burr can be removed. So, if you don't want to use a strop, develop good technique. Me I like what a strop does and enjoy using it on most any edge. But atleast get a 5X magnifier. DM
 
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