Smoothing edges on a Traditional Slip Joint

Archie

Gold Member
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Oct 4, 1998
Messages
235
If I had a traditional slip joint where the either the liners or backspring were slightly proud, what would be the best technique to smooth the sharp edges? I'm not looking to grind anything all the way flush...just break the edge so it's less noticeable in the hand. Sandpaper? File? Sharpmaker rod? Depending on how careful I am, whatever I use could end up contacting brass liner, steel backspring, and maybe the handle scale. I would think I would need to use something relatively fine to not leave visible scratches. I'm just not sure where to start. I've never ground any part of a knife other than the blade edge.
 
You could try these. The best results would be to grind the components flush then polish with progressively finer grits then wash out the knife with mild solvent to get the grit out of it.

But to just debure along the edge of the spring etc.
This is an Ultra Fine stone from Spyderco; you might want to get the next coarser one for faster metal removal. Just use the very end of it where you see the red color. That color seems to be not paint but wax. It rubs off with use. The end is pretty square and sharp (forget about using the long sides they are rounded and won't get down in where you need them to.
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Or get one of these diamond coated steel paddles. They have plastic handles but the actual metal plate is pretty thin and the grit goes right to the edge of the metal plate. They are inexpensive ($10 to $15 each). The blue one on the far right is probably the one to get it is very fine but still aggressive. You can buy them individually or in sets. Very handy.
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And finally and it may sound insane but I think it could work is the CARBIDE box knife blade shown here. The edge material, in theory, is harder than the material in the knife so it should cut a curl off the corner of the sharp edge on your knife components and effectively make your knife more friendly in hand. You can buy the box knife blades by them selves in small quantities. Don't push hard just let the edge do the work otherwise you may chip off the cutting edge.

Let us know what works.
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PS: as far as deburing the brass liners sand paper or a file should do it or the box knife (or about any other sharp knife). Brass is soft.
 
It takes almost nothing to take the 'bite' out of the hard edges of liners & such, especially if they're brass or nickel as with most traditional knives. You might even be able to do it by (lightly) burnishing the edges with the tip of a steel screwdriver or something similar. I'd minimize any use of abrasives, as it may not even be necessary, and the swarf or loose grit generated could get into the gaps or pivots and create new friction-related problems with sticky joints.

With steel springs, a minimal abrasiveness might help in softening the hard ends/edges of the spring. A fine emery board, or a small piece of 1000+ grit wet/dry sandpaper wrapped over the tip of a screwdriver could be used for that. Again, with that tool, a minimum of sanding/grinding should do it, maybe just a pass or three.
 
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Perhaps a jeweler's file? Being small you can really do precise cutting with them. You can get a full set of them for less than $10. (I see that they all seem to come with diamonds now in various grits. Mine are older and have milled teeth.)
 
I have used an old round ceramic crock stick to knock the edges off a soft material liner.
 
600 grit wet/dry sic sandpaper wrapped around a credit card. Gives you plenty to hold onto for control & is abrasive enough to dull those sharp edges.
 
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