How to sharpen near the Heal or rear of knife with a Sharpmaker?

D

dextersp1

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Jun 1, 2007
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The 1/2" of the blade at the heal or rear of knife is not as sharp as the other parts.

Are there any tips on how to sharpen it?

I have a Kershaw Needs Work in 13C26.

The other parts of blade I can do some good push cuts of newspaper. The rar 1/2" doesn't cut very well.

I'm guessing it is because that part of the blade spend the least amount of time on the stones.

Is it proper to just go straight down on the rods instead of a slicing motion?

Thanks
 
Ditto what Sword said. Slow down your slice on the first part of the edge. I mean, spend more time going almost straight down the rod and less time slicing toward yourself. It's slight but perceptible. You'll get more "stone time" on that section without digging into the edge. It's like sharpening the tip without rounding off, both sections require attention and a slightly different technique than the rest of the blade.
 
It's pretty common with many production knives that the rear 1/4"-1/2" isn't sharpened the same, or sometimes as thoroughly as the rest of the blade -- often you find the factory edge bevels in that area more obtuse. Add to that, as you and others rightly note, that part of the blade tends not to get as much "stone time" when sharpening unless you deliberately focus on it.

You might try using the flats of the Sharpmaker rods working straight up and down on the area, unless a lot of metal needs to be removed. In that case you could wrap the rods with medium-coarse abrasive paper to speed up the job.
 
Asides from the more obtuse angle, it can also be the cause that there is a slight recurve in that area, if this is the case then the flat will never hit it well at all and you will need to use the corners. Check this by laying the edge directly 90 degrees to a sheet of paper and making sure that it all makes smooth contact.

-Cliff
 
Cliff Stamp said:
Asides from the more obtuse angle, it can also be the cause that there is a slight recurve in that area....
Click to expand...
Yes, you see that quite a bit. I prefer to remove the recurve on a benchstone or with a file.

In fact the surprising thing about factory edges, which tend to be quite inconsistent, is that they seem consistently like this near the back, and horribly more obtuse near the tip ... which of course means only one thing, that it's quicker and easier to do it this way.
 
Dog of War said:
...is that they seem consistently like this near the back, and horribly more obtuse near the tip ... which of course means only one thing, that it's quicker and easier to do it this way.
Click to expand...

The tip is thicker steel as it is up higher on the grind and thus to keep the bevel the same width it will be made more obtuse. As for the heel, I have noticed that myself in belt sanding. It is easier to sharpen fully with a notch choil or similar. Otherwise there can be some hesitation in the start of the pass which leads to the irregularity. I found this had happened after a few years with the Mora 2000 and had to regrind it back straight.

-Cliff
 
Nearly every knife I own (mostly folders) came with a thickness at the heel of the blade which makes it almost impossible to attain optimum sharpness at the heel of the edge.

To remedy this, I usually:
- Use dremel cutoff wheel to install a small choil notch (about 3/32").
- Use the edge of diamond or coarse stone or supported sandpaper to grind this area down to match primary bevel angle.

There are some exceptions, such as a Benchmade 806D2 and a Buck/Strider Tarani, but every Spyderco folder I have exhibited this grind problem at the heel of the blade.

Regarding point/tip sharpening, using sharpening rods will almost certainly result in a rounded tip. I like the little hand-held Spyderco DoubleStuff stone for dressing the tip, treating tip-sharpening as a separate operation. Test for tip-area sharpness and tip penetration with newsprint.

Hope this helps!
 
How long an area is typically effected on the Spydercos?
Click to expand...

Two answers:
- Without treatment, about 3/8" to 1/2" at the heel of the edge is difficult to sharpen.
- To install a full 10 degree bevel to the heel of the edge requires removing a lot of metal. Bevel grind marks extend up to 1/4" from the edge in this area, about 1/8" length.

It's not my intent to bad-mouth Spyderco, as I consider Spyderco the best overall folder-manufacturer and I haven't bought folders from any other manufacturer in a long time. It's worth the effort to cure this small problem.
 
That is interesting, I typically regrind all of mine with the exception of the Calypso Jr. and similar already < 0.005"/10 edged blades and have not noticed a variance of that size. Of course for every distribution there will be those at both extremes.

-Cliff
 
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