SharpMaker Questions

N

numbersman

Joined
Nov 28, 2010
Messages
596
Hi guys, just a couple of questions about my SharpMaker.

1. Is there really any point in sharpening on the edges? OK, for serrations and hawksbill blades, I can see the point. But for plain blades, wouldn't you get more steel off per pass using the flat sides?

2. After a while, don't you reach a point where the edge is as sharp as it's going to get with that stone? I don't have the ultrafine stones yet, just medium and fine. So surely I can't keep getting the edge sharper just by carrying on with the fine stones. There must be a limit. So jow can I tell when I have reached that limit?

I do strop with a leather belt from time to time, and check the sharpness on my arm hairs. But I find it hard to get it shaving the hairs of my arms easily. My plain edges are a Dragonfly, an Opinel (which gets scary sharp easily) and a cheapy Lebendwell.

Cheers, numbersman.
 
1. i rarely use the sharp sides, except for hawkbill and serrations. but after i sharpen my knife, i like to slide the edge on that sharp edge to 'strop' it.

2. as for "when to stop?" i use what to be common sense when i sharpen: i create burrs, i remove the burrs. same applies when i sharpen using sandpaper. that said, i do realize there is a difference, of course the uf stones create finer edge than the fine stones.
 
1. The edges of the rods provide more force at the edge than the flats and therefore remove metal faster. The smaller surface area actually grinds faster. That being said, I've stopped using the edges, except for serrated blades. I like the larger surface on the flats for more stability. I also have abandoned the Spyderco suggested method of back and forth strokes and now do it ALA JDavis. Like he does in this video. He starts showing the technique around the 2:30 mark.

[video=youtube;-MHe_8wTHmg]http://www.youtube.com/watch?v=-MHe_8wTHmg[/video]

2. As the previous poster said, you know you are done with one side of the blade on one stone when you form a burr. The burr is probably the most important concept in all of sharpening. Read up on it and your sharpening will probably improve dramatically! :)

Brian.
 
Yes, the corners (edges) exert more pressure per unit of area, so they'll work more aggressively. I think this is why the SM's instructions specify starting on the corners of the brown rods first. There's more risk of rolling/burring/chipping the edge for the same reason (heavy focused pressure), so extra care needs to be taken when using the corners of the rods.

Having said that, I generally avoid using the corners at all, for regular maintenance or light touching up. If I do use them, I do so with feather-light strokes; just enough pressure to keep the bevel in contact without skipping/bouncing.

To the second question (how far to go/when to stop?), that also depends on how you use pressure, to some extent. As the edge becomes finer and sharper, it's always good to gradually decrease pressure as well. It's possible to refine an edge quite a lot on one grit, if one pays attention to how fine the edge is becoming and how it's performing (with frequent test-cutting), and modifying pressure based on that. There will be some point at which you'll notice a cessation in progress (steadily improving sharpness), but a lot of that depends on individual skill and experience. Just keep testing the edge (cutting paper or whatever), and test it more frequently as you notice you're getting very close.


David
 
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I know quite a few people that dont use the edges on the Sharpmaker to sharpen their knives so it must work okay without it. I plan on sharpening mine the same way the jdavis video shows as I too think it is easier and faster doing one side at a time. I have the Sharpmaker w/UF rods. :)
 
Numbersman, how long have you had this? I use one, along with my DMT's. I have all 4 sets of stones for it. As far as "how long", that is up to you. I just sharpened my ZT 0350, for a couple of hours, through all four sets of stones. What did I get? A mirror polished edge, that cuts like hell. So that part is up to your preference and needs.

As far as your sharpness test, that one concerns me. With just the brown stones alone, you should be able to get a hair burning, newspaper pushcutting edge, that will cut the hell out of you. I have some of my "working" knives, that I sharpen a couple of times a week, and that is all I use on them, other than a bare strop. If I had to guess, I would think that your technique needs a little practice. Good luck man.
 
I reprofile with the diamonds & will use the corners of the brown stones on a touch-up if I see a lot of light reflecting off of the edge when viewed straight on. It does seem to work a bit faster.

I move to the flats & finish up on the browns with very light, controlled alternating strokes. This is the edge I use for other people's knives that I sharpen & my wife's kitchen knives & S90V Para that she does crafts with. It leaves a somewhat toothy edge that will still push cut cleanly. I only use the fine & UF stones when I want a flashy, freaky push-cutting edge that won't be used often.
 
numbersman said:
Hmmm, maybe I'm just not sharpening long enough!
Click to expand...

Numbers, the SM can do 2 things well. Sharpen the hell out of knives, while it frustrates the hell out of the next guy. Do you freehand at all? On your SM, have you used the sharpie trick? Are you fully hitting the bevels? If there is a question of hitting the blade fully, get the diamond stones, and do some reprofiling at 30 degrees, and then proceed. Or, you can get a DMT coarse, and thin the edge like that. I do both.

What is a MUST for the SM to work properly, is a properly thinned edge. Once this is done right, the edges that you will get, are really amazing. If you aren't hitting the edge fully ie. hitting the apex, you are wasting time, and getting mad. I hope this helps out some. When you do figure out what the most likely small detail here is, you will be more than happy with your results.
 
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