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How to finish (smooth) choil and spine?

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kdkrone

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One of my knives could use some rounding (smoothing) of the choil and spine. How is this most easily done? Is there a cloth similar to emory cloth that could be used (similar to how a shoe shine is done, held in each hand and pulled back and forth with the knife secured in a vise?) Any suggestions for equipment/technique would be appreciated.

Thanks
Ken K
 

milkbaby

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Yeah, I just use sandpaper in strips and back it with tape so it doesn't tear apart as easily. If you're adventurous, you can also use a power tools like a dremel or a belt sander, but be careful because they can build up heat (don't want to ruin the temper/HT) and once you remove metal, you can't put it back... ask me how I know that, LOL
 

bkultra

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Same... Small piece of sandpaper and use a back and forth motion, like shinning a shoe.
 

kdkrone

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Thanks to you both. I had not thought of backing the sandpaper with tape--smart. What are equivalent sandpaper grits to, say, 800 and 3000/5000 grit stones? Are the nominal grits printed on sandpaper equivalent to stones?
 

Matus

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I use belt grinder with the platen removed to give a slight radius to the spine snd finish by hand with a sandpaper on a semi-hard support.

Forvthe choil I use a rotary tool (like a dremel) with those sanding drums and again finish by hand
 

kdkrone

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Thanks, Matus. I have a few old knives I could practice with, as I have a dremel tool. Even just creating a 45 degree bevel along each edge would make the finishing with sandpaper easier...

Again, thanks all for the good advice.
 

zizirex

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I use a drill with sandpaper attachment, and finish it with buff attachment with brown tripoli compound follow by ChrOx compound.
 

M1k3

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Put knife in vice or similar holder, spine up. Strips of sandpaper, some might need tape backing, and do the shoe shine way. Flip knife over and hold the sandpaper the same way but on the choil.
 

NO ChoP!

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If one is delving into the jknife world, a progression of sandpaper would be a wise investment. Something like 120-220-320-400-600-800. (1k-1.5k-2k, if going for mirror) Rhynowet and 3M Cubitron are my favorites. Norton and Gator are pretty popular, too. Most come in 3 or 4 sheet packs, that can be cut into squares or strips. Maybe a pack of 0000 steel wool, too.
 

Danzo

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Clamp in a vise, then I use a file first. It will be super fast, then finish with sandpaper to at least 800 or higher if you want to polish it.
 

HRC_64

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As some have said earlier if you slightly dull the edge (target) it will work better
 

Kippington

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Clamp in a vise, then I use a file first. It will be super fast, then finish with sandpaper to at least 800 or higher if you want to polish it.
Kato style.

Should be said just in case: Don't bother using a steel file on hardened steel.
 

RDalman

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I would say file should work on anything ~63 hrc and less. It will wear some on the file, and if on the hard side steel, use a smaller round file, like a chainsaw file maybe, just mind your strokes to work a larger radius in each.
 

Luftmensch

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dremel or a belt sander, but be careful because they can build up heat (don't want to ruin the temper/HT) and once you remove metal, you can't put it back
Good advice.

On the thin parts of the choil and the spine at the tip there is a risk of ruining the temper. On the thick part of the spine spine, the risk is low to nonexistent. There is a lot of material to dissipate the heat and you are far from the cutting edge. It is the speed of material removal that is the biggest danger.
 

Chef Doom

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Send it to Jon at JKI.

Why work hard when you can get others to do it for you?
 

HSC /// Knives

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Nice! Really well put together video

Spotted a continuity error though... :D You etch the blade (with rounded spine) at 2:15... then round the square spine at 2:45 :p
thank you for the praise,

yes there are likely other imperfections ;)
probably the blade during etching was roughly rounded on the grinder which I generally do anyway.
Rounding the spine with the finishing film gives a more uniform crown radius and smoother polish at 20 micron.

I did say in the video notes that there are 2 different blades used over the course of several days of shooting.

Nice music, is it the ghosts album?
honestly don't know, i left that up to the video production
 

Benuser

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I don't like the use of powered equipment with knives. Just don't feel comfortable with it.
In fact, very little needs to be removed. Any abrasive can be used. With a medium-coarse stone, you may strop — edge up this time. Easy as it is a familiar motion.
 

nutmeg

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Thanks, Matus. I have a few old knives I could practice with, as I have a dremel tool. Even just creating a 45 degree bevel along each edge would make the finishing with sandpaper easier...

Again, thanks all for the good advice.
Sand paper is good. I use the 300-1200 range.
You can try coarser but you don't need it. You don't want a totally round spine.
Dremel ONLY for polishing with the softest cotton at full speed with lot of polish wax. With enough wax this won't heat so much to damage anything. (Anyway you won't never get much heat on the spine)
Don't use a dremel for grinding or shaping anything. This tool doesn't give you enough control on your work.
Hands are much more precise.
 
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