Looking for Reprofile Advice

mrgreen

mrgreen

Joined
Dec 26, 2009
Messages
313
Hi, I'm starting to reprofile a blade of 1095/15N20 Damascus ( unknown RC, but supplier is Aldos). I'm changing it from the original convex to 17deg per side. I've started with a WEPS 50 grit stone. After about 15 minutes I'm still not hitting the edge. Is this to be expected with this steel/stone combination? Is this a good working angle for this steel?

Thanks in advance,
 
A bit more info would be good here. How big is your knife? Is it a large camp knife/chopper, a small EDC etc.? I guess for a smaller knife most reasonably treated steels would support 17 dps, most even 12-15 dps. That is takes you a long time tells me that the blade thickness before sharpening was likely "overbuild", hence a convex edge. If a knife geometry is right, the actual edge is only a thin hairline. A picture would be helpful too!
 
It's a smaller knife, with an upswept pattern like a Sharpfinger. Digging a little deeper, I believe the specs are 3.5 inches long about 1/8 or 5/32 thick 1095/15N20 Damascus RC 58. Hope that helps, I'm away from the knife and don't have a pic with me.

Thanks
 
What is the width/height of the new bevel now? Most of the time progress will be slow or coming to a halt as the bevel grows wider because lack of pressure. e.g. when bevel width=2mm you use X amt of pressure, steadily you need to increase the pressure to 4X as the bevel widen to 4mm. Since the contact area increase at square rate (bevel_ height*stone_width). Progress to the 100 or 150 grit stone - from 50grit - when the apex about 80um. Progress higher when 50grit scratches are gone. so on...

1/8 or 5/32 is fairly beefy/thick for a 3.5" blade, so the contact area will be large. Hence use heavy pressure to cut new 13dps bevel. Done when apexed or apex width around 20-30um. Final step is to create a 15-17 dps cutting bevel. Later one, after usage and multiple sharpening, you can re-thin the back bevel to 13dps to 20-30um again.
 
While I agree with Bluntcut's theory, you really don't need to use that much pressure, especially with the 50g stones.

Convex edges are often at a greater angle than most people realize, so a reprofile does take time. Unless the bevel is getting unusually wide, there's probably nothing wrong with the fact that it's taking a while.
 
Thanks guys, some great points here. I think I'm more comfortable with cbwx34's approach. Kind of "steady as she goes", There's no rush. If I start applying more pressure it increases the chance of my screwing up the angle.
 
I would take a long hard look at the knife in question and really imagine how the stock is going to come off as you create the edge you're shooting for. With a thick spine, you could very well be setting yourself up for a manually worked FFG or something very similar - a lot of stock removal for a very small gain ultimately in performance.
 
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