Sharpmaker and Kershaw Spec Bump

[merciful]

Hey there,

I can get a forearm-cleaning edge on my Kumo, Wenger Swiss Army, Kershaw Blur, and CRKTs; but not the CPM154 Spec Bump. It's sharp, but not what it should be: certainly not at all what it was when I got it. I've tried a lot of strokes through the 40º setup, and the 30º and then 40º routine, but no dice.

If anyone has experienced this, I'd love to hear. I'll be out of town all week and drinking far too much Montréal brewpub beer to check then, but I'll be reading on my return.

[uhiforgot]

Hey there,

I can get a forearm-cleaning edge on my Kumo, Wenger Swiss Army, Kershaw Blur, and CRKTs; but not the CPM154 Spec Bump. It's sharp, but not what it should be: certainly not at all what it was when I got it. I've tried a lot of strokes through the 40º setup, and the 30º and then 40º routine, but no dice.

If anyone has experienced this, I'd love to hear. I'll be out of town all week and drinking far too much Montréal brewpub beer to check then, but I'll be reading on my return.

Hey, Merciful, welcome to the forums!

I have no experience with CPM154 (you sure it's not 154CM?) but I do have experience with sharpening odd blade shapes such as that on the Spec Bump. Ken Onion really did it right when he designed that one!

Ideally you should keep the edge of the blade that's in contact with the sharpening rods parallel to the surface that the sharpmaker is on. This means changing the angle of the knife itself relative to the surface you're working on while moving down the sharpening sticks. It's slow; it's awkward; it takes more patience than most have, but it's the only way to really get the results you want. If you got the sharpmaker DVD, watch it. If you don't: get it! There's a lot of extremely useful information and techniques in there that are invaluable to know!

-Jeff

[ghostrider]

It's possible that the Spec Bump may just be more abrasion resistant, and require more work. Have you tried the magic marker trick yet? I always recommend getting one of the pocket microscopes at Radio Shack for about $10. They allow you to actually see where your taking off the metal.

I would say that if you haven't tried the magic marker trick, then that would be your first step. Check the ink after each stroke to find where your hitting on the edge. There is no reason you shouldn't be able to get it sharp on the Sharpmaker.

BTW: Welcome to the forum.

[smcfalls13]

I never had any problems sharpening a Spec Bump when I had one. The recurve may be problematic, but I sharpen Hawkbills routinely, so a recurve isn't all that much more difficult.

That particular blade comes plenty sharp from the factory. Not sure what could be wrong, apart from user error, but if you can sharpen all those other knives you mentioned without a problem, I can't see how the Spec Bump would cause problems.

CPM154(or 154CM, can't remember which one the Spec Bump has) is very easy to sharpen. Possibly a poor edge bevel from the factory is all I can think of.

Good luck.

[merciful]

Thanks, Scott. I tended to think user error, too, but the others are all wicked sharp. Perhaps there's a problem with me and recurved blades: I just saw this thread and will probably put the sharpen-by sections technique to use.

Thanks again.

[merciful]

Thanks, everybody. I'll give the marker trick a go, rewatch my video, and mind the position of the blade relative to the surface I'm on.

Thanks for the welcome, you guys are good with a new guy.

[smcfalls13]

You may very well have an achilles heel when it comes to recurves. I for one can't sharpen a chisel ground knife to save my life. They're supposed to be idiot proof to sharpen, but for some reason the technique just eludes me.

Keep practicing, and you'll get the recurve eventually

[Joshua J.]

Incorrect angles and burrs are usually the reason someone can’t get a knife sharp. Like ghostrider said, make sure you are grinding the edge. You may just need to work at it longer (I would suggest getting the diamond rods to speed things up). For de-burring, make sure you are using light pressure when switching to the forty degree angle. Also try stropping, it makes a big difference.