RC 4 sharpening question

fatheadhill

fatheadhill

Joined
Mar 30, 2008
Messages
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I have an RC4 that I just cannot seem to get sharp. I'm by no means an expert sharpener but have been able to put and maintain a shaving sharp edge on all my 30+ other knives but I just can't seem to get my RC4 sharp. I started out just trying to work it on the sharpmaker but couldn't seem to get an edge on it, so after getting frustrated I put it on the Gatco and I've got it pretty messed up now since I put it in the Gatco sharpener(this one) and worked the edge at 11 degrees per side thinking somehow this might change the angle and make it able to be touched up on the sharpmaker, which is all it usually takes on my other knives. I don't know what to do now. The knife is ugly now, lol, cuz I've got the coating pretty messed up due to working it at such a shallow angle, but it'd still be usuable if I could just get a decent edge on it.

Just curious what you guys thought I should do now.., keep working it on the Gatco till the edges comes together or start working it on the sharpmaker?? angles?? thanks in advance for the advice!!

These are the sharpeners I have
Gatco I linked earlier
DMT Aligner
And the sharpmaker

P.S. think I'll have to order another RC4 just so I have a pretty one again to go with my RC3, Izula, and the RC5 SERE I'm eagerly waiting to get!! :D
 
I haven't had any real difficulties getting my RC-4 sharp. I used a Lansky, similar to your gatco and thinned out the edge. You don't want to go super thin, however, as that sort of misses the boat on having a 3/16" thick blade.

From what you have posted, it sounds like you stopped too soon on the rebevelling exercise. If you don't continue a rebevel until you raise a bur on each side of the knife, you never hit the edge. So all you've done is thinned out the metal a bit. What I would do if I were you, would be to go through the medium and fine stones lightly at the same angle you started the rebevel at. Just to get that bevel shiney and nice looking, not trying to hit the edge.

After that I would use the sharpie trick on the edge. Put on a fine stone and do some trial hits by stepping up through the angles until you find one that hits the edge. If you want to rebevel again, drop back one preset angle that is more acute to the one where you hit the edge. Switch to a course stone and start to grind like a mad man until you raise a bur evenly along the entire edge. Switch the stone to the other side and again grind like a crazy dude until the bur is now raised, and evenly so, on the opposite side.

Now switch the stone to the other side, do about 20 controlled strokes. You will notice that it raised a bur right away. Repeat on the other side. Flip back and forth about 4 or five times. You may not need a full 20 strokes, 10 may do it. Repeat the 10-20 strokes /side for 4 or five cycles with the medium and and fine stones.

At the very end of it all, set up the sharpmaker with the white stones in the 20 degree slots. Use very light strokes strokes, 1 per side, for about 10 strokes in total to get a micro-bevel. This should push cut paper nicely and shave arm hair with ease.

The Key Is To Not Give Up On the Course Stone Too Early. If you don't raise a bur on the edge with the course stroke then you aren't done. Depending on how much metal you are removing this could take 40 min or so

Good luck!

P.S. I convexed my RC-4 and its fantastic that way too!
 
thanks man for such a detailed answer!! Sounds like that may do the trick!! I'll keep at it!!
 
I kept mine at the 20 degree angle for the RC4 which matches the factory bevel. However, the way in which you fix the guide holder to the blade will influence the final angle. Usually when I work on the lansky, I resign myself to do a complete rebevel. I maintain the edge using the sharpmaker for as long as I can.
 
Here is a picture of an RC-4 in V-grind and as convex (the uncoated one). It took a while for the convex conversion, but I really like how it performs now!

There are a few people who specialize in after market conversion of edge grinds to convex. Siguy is one of them, he converted Bearthedog's RC-3 if I recall correctly.

DSC_0006-16.jpg


DSC_0007-1-2.jpg
 
kgd,

Does putting a convex grind on a blade make a knife longer or is there an optical illusion in the bottom photo? :p
 
All that stropping stretches the blade....and also the truth ;)
 
looks nice KGD! I've been considering stripping my RC4 since I've alreay got the coating messed up due to my horrible sharpening!
 
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