Becker BK7 Sharpening Question

D

Dave568

Joined
May 24, 2005
Messages
118
My BK7 was shaving sharp out of the box. After a decent day's worth of use, it was still sharp, but not shaving sharp anymore. I decided to go ahead and sharpen it on my Spyderco Sharpmaker. I went ahead and sharpened it at 40 degrees, following the regular sharpmaker rules of 20 strokes to each side for each of the 4 steps. However, the end result was one dull BK7. I tried again, and again, and again. I still have not been able to get the BK7 sharp enough to even slice paper. Maybe I am missing something here... maybe it is the steel, the blade size, or the blade shape, but for some reason I just cannot get this blade sharp. I went ahead and sharpened some of my smaller folding knives right afterwords to see if it was my technique, but I was able to get them all scary sharp in just a few minutes. Does anyone know what I might be doing wrong? How do you all sharpen your BK7s? Thanks.
 
Are you saying it went from "not shaving sharp" to "dull" after using the Sharpmaker? Don't know how that could be....???

If it's just not getting any sharper it sounds like the edge profile is too obtuse -- > 40 degrees -- so you're not hitting the very edge. Becker edges I've seen have had sections > 40, so you may need to reprofile. You could also tilt the blade out just a little when working each side to increase the sharpening angle on the Sharpmaker if you're ohterwise happy with the edge geometry.
 
It sounds like you are not hitting the edge but the shoulder. It is common for large knives to have edge bevels above 20 degrees, or even bevels like 15/25, and thus they need to be reprofiled before a Sharpmaker will work effectively well. Take a coarse hone and rip the primary bevels down to 15 degrees and then rehone on the Sharpmaker.

-Cliff
 
Thanks for the replies. I don't really have any equipment to reprofile an edge right yet (I'm a knife newbie), so I'll have to look into that. All I've got in terms of sharpening is a Sharpmaker with the standard ceramic rods. Does anyone have any suggestions on how I should go about reprofiling it?
 
It will take a long time with the ceramic rods, as in possibly hours. You can pick up a cheap x-coarse hone at any hardware store which will allow the metal to be removed easily in under ten minutes. Look for something called an axe or garden stone. They will usually cut much faster when wet. If you want to reprofile with the Sharpmaker use the corners of the medium rods and press down hard. You will also likely have to wash them a couple of times during the process as they will load up heavily.

-Cliff
 
Thanks for the reply. I'll look into the garden hone. I've never successfully sharpened something freehand, so this is going to be quite an interesting experience. Thanks for all the help.
 
You don't actually sharpen it freehand, just reshape the edge so you can sharpen it on the Sharpmaker, just eyeball a 15 degree (it doesn't need to be exactly under 15, just under 20) and hack the metal off.

-Cliff
 
I just finished reprofiling and sharpening the BK7. I still need to spend a bit more time sharpening it, since it isn't exactly shaving sharp yet, but it is able to slice paper and scrape hair quite easily. Thanks for the advice everyone. :D
 
Dave568,

Did you use your Sharpmaker to reprofile or did you use a coarse stone?

Thanks
 
If you are careful, a bastard cut mill file will let you reprofile in a hurry. I just reprofiled my BK-2 companion this evening from abour 25 per side down to 15 per side in about five minutes. You have to be careful though, it is easy to mess up a blade if you don't know what you are doing with a file.
 
BillL said:
Dave568,

Did you use your Sharpmaker to reprofile or did you use a coarse stone?

Thanks
Click to expand...

I used a coarse stone I picked up at a hardware store down the street.
 
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