So I just bought a new Spyderco Sharpmaker and a Benchmade 940 Osborne...

Kamoe

Kamoe

Joined
Sep 30, 2012
Messages
183
The knife is still hair-popping sharp, but when it gets dull, what angle should I sharpen my 940 on my Sharpmaker at, 30° or 40°? I did a bit of hunting on Google and I could not find out what the best option would be, so I decided to ask here.
 
Boias.John said:
The knife is still hair-popping sharp, but when it gets dull, what angle should I sharpen my 940 on my Sharpmaker at, 30° or 40°? I did a bit of hunting on Google and I could not find out what the best option would be, so I decided to ask here.
Click to expand...

You can strop it up for a while (a dozen time or so) until it's too convexed or dull, then sharpen it to a 30* inclusive. My 940 s30v has ~24* back bevel and 30* cutting (~0.5mm convex) bevel. I can't remember how thick behind the edge originally, since I reprofiled mine so the saber grind is only 5mm from the spine. 1st sharpening will take more effort than subsequence maint sharpening.
 
Would it be possible to sharpen S30V with the two sets of stones included in the sharpmaker's setup? Or would I have to buy the diamond stones they sell so I can remove metal more effectively? This is my first knife with a high-end steel like S30V, the rest of my knives are made out of AUS-8 or 8cr13mov and they sharpened rather easily, so I'm a little uneducated concerning S30V, and I wanna be careful because I really don't want to damage the edge.
 
Here is how to sharpen to get hair popping sharp with your Sharpmaker.

First sharpen at the 30 degree angle until the knife is very sharp. This is called the "back bevel" angle.

Then sharpen at the 40 degrees for the final bevel angle. You will get a very good blade edge with your sharpmaker.

So it is 30 degrees first, then 40 degrees. The 40 degrees is the optimum edge angle for long term cutting, the 30 degree back bevel allows you to sharpen at 40 degrees several times without have to rebevel the edge.

Here is the first of a four part series about using the sharpmaker that will be of help to you. It is well worth the time as it is presented by Sal Glesser, spyderco owner and inventor of the Sharpmaker, his first commercial knife related product. He has probably sharpened hundreds of thousands of knives in his lifetime.

http://www.youtube.com/watch?v=GB0r6GvESGg
 
I'll definitely try that on some of my knives. I have a spare Tenacious that's so dull I could run my fingers across the edge with no consequence, it'll be a fine experiment. Thanks for the recommendation. :)

That did not take long, my dulled Tenacious is now hair-razing sharp after trying the 30 to 40 degree trick.
 
Last edited:
I watched all 4 videos - they were helpful for most users however a bit contrive. It would have been better if Sal introduces the Diamond Triangle, than stated that the ceramic will abrade all steel & carbide types. Diamond Triangle is the right tool for abrading Vanadium Carbide, especially when VC percentage exceed 1%. S30V has 4% of VC.

Many skills sharpeners can get high alloy % of VC steels pretty sharp with ceramic but will encounter more difficulty as the bevel drop around 30 or below and along with a high grit finish. You need diamond to abrade away VC - critically so when abrasive size goes below 10microns.

having said that... lol - I sharpened my bm940 using a coffee cup before, almost shave with it, so we knuts should enjoy tinkering around. S30v will tko you before it taps - let's grind.
 
So for me, a beginner sharpener and newbie to the knife realm since I've only been into knives since the beginning of this year, would you recommend the diamond stones for sharpening S30V? And if so, what would the steps on the sharpmaker be when you include the diamond stones?
 
I have never used the diamonds, ceramic is harder than the finest steel. Lots of guys take too much steel off the edge when they sharpen. Only sharpen until the blade is sharp enough, check it after a couple of swipes on the sharpeners. I can tell if it is getting there if it will stick to the edge of my thumb nail without sliding off. Remember, you are sharpening a knife, not a razor. They are very different types of edges.
 
I see, very interesting. So with that understanding, I'm assuming the diamond blades are more for removing a lot of metal to repair something like a chip or a botched sharpening job? Sorry for asking a lot, I just want to understand what does what in the world of the sharpmaker, I'm a newbie sharpener so I need all the information I can get.

Oh, and one more thing. I don't have a strop yet, so for maintaining an edge with S30V steel, do I go through the entire 4 step process for the sharpmaker if it's still sharp? Or can I just do steps 3 and 4 on the ceramic rods? Just keeping the edge sharp, not to entirely resharpen a totally dull blade. Or would I have to go through the entire 4 step process on 30 degrees and again on 40 degrees since it'd be my first resharpening on a factory edge?
 
Last edited:
Boias.John said:
So for me, a beginner sharpener and newbie to the knife realm since I've only been into knives since the beginning of this year, would you recommend the diamond stones for sharpening S30V? And if so, what would the steps on the sharpmaker be when you include the diamond stones?
Click to expand...

Diamond is always more aggressive than ceramics, meaning it cuts deeper and it'll remove metal much faster. I would recommend diamond for S30V, at least at times. If your S30V edge is already in good shape, the ceramics can help maintain it, or even fine-tune it. BUT, if you ever fall behind on maintenance, an S30V edge will not come back easily or quickly on ceramics alone. Use the diamond to reset the bevels first, then refine with the ceramics (med/fine/uf) after that.
 
Last edited:
Excellent. That's just what I needed to know. So after a few maintenance resharpenings, it'd be wise to re-set the bevel on 30 degrees, then 40 degrees for a hair-popping sharpness?
 
John - hold off from buying the diamond rod for a day or two, I'm making a home-made VertiSharp you might be interested. Yep, a better sharpmaker and dirt cheap and better for a freehand future too.

Will see how far I get after dinner, will post a picture of all pieces and reasons why.

Catchy name for an elcheapo sort-of-guided sharpner.

edit: a $50 - Dmt 4" C, EF, EEF + a 8" hinge + a C wood clamp + a piece of scrap wood. Chuck the guide when go freehand.
 
Last edited:
Benchmade edges are often obtuse -- more than 45 degrees. So while it is good advice to set the main edge angle to 30 degrees and then add a 40-degree microbevel, in reality you may need to remove a whole lot of very hard steel to get to the 30 degree edge. The diamond rods will help a lot, but it could still be a ton of work.

However, once you get the 30 degree bevel established, it is a snap to sharpen the knife thereafter with just the 40-degree Sharpmaker stones. You can just sharpen at the 40-degree setting for many sharpenings (probably with just a few, light passes with the fine or ultrafine stones), never messing with the 30-degree stones. As the microbevel shoulders get wider with repeated sharpenings, you would just reset the 30-degree back bevel and start the cycle all over.

Check out the microbevel sticky here. It's very good and has some diagrams that will help.

Your biggest issue will be setting the initial 30-degree back bevel. I don't like the Sharpmaker for reprofiling an edge, but it works great for keeping the microbevel sharp.

The other skill you want to learn is how to raise and recognize a burr and how to gently remove it. When one side of the edge meets the other at a perfect point, a burr is formed, telling you that you don't have to remove any more metal, as long as you raise the burr the entire length of the edge. Then you just remove it with very light passes with fine stones.
 
Twindog said:
Benchmade edges are often obtuse -- more than 45 degrees. So while it is good advice to set the main edge angle to 30 degrees and then add a 40-degree microbevel, in reality you may need to remove a whole lot of very hard steel to get to the 30 degree edge. The diamond rods will help a lot,
but it could still be a ton of work.
Click to expand...

:thumbup: exactly, the 940 is really thick behind the edge (mid-height saber grind), so alot of grinding to set a 30* back bevel.
 
I will definitely check that sticky out. Thank you all very much for the information, I learned a TON here, I think I made the right choice joining up. :)
 
But a perfect point doesnt have to be 40 degree angle on both sides or the same angle on both sides.

You can get razor sharp if each side doesnt match too. You could leave one side obtuse and just work the other I should imagine?
 
coping said:
But a perfect point doesnt have to be 40 degree angle on both sides or the same angle on both sides.

You can get razor sharp if each side doesnt match too. You could leave one side obtuse and just work the other I should imagine?
Click to expand...

A very asymmetrical edge can still cut. BUT, if it's too lopsided, the blade will tend to try to 'turn away' from the more obtuse side when cutting. If you're wanting steady control and a straight cut, that might be a problem. A couple or three degrees difference between each side is usually tolerable, but if it's much more than that, you'll start noticing a lot more resistance in the cut, or you'll start feeling the blade attempting to 'steer' itself to one side or the other. The asymmetry might also be a bigger problem for tasks like carving or whittling, where firm control of the direction of the cut is more important.
 
Boias.John said:
Excellent. That's just what I needed to know. So after a few maintenance resharpenings, it'd be wise to re-set the bevel on 30 degrees, then 40 degrees for a hair-popping sharpness?
Click to expand...

That's up to you. Many or most who use the Sharpmaker will do it that way (30° back bevel, and 40° micro bevel), and that's fine. But, if you choose not to add the 40° micro bevel, that's OK too. I'm sure the S30V blade can handle the 30° edge. The 40° micro can make it a little more durable, if you use the knife fairly hard.
 
My main tasks include cutting a LOT of cardboard, tape, plastic zipties, and sometimes cloth of varying materials. I know, having S30V for cutting cardboard is a little odd, but having AUS-8 blades or 8cr13mov showed a lot of dulling, requiring a good re-sharpening every few days. I got the S30V mainly for convenience of not having to sharpen nearly as often. After two full work days of cutting over 100 boxes and an equal amount of tough plastic zipties, my 940 is still as sharp as it was the day it arrived with no touchups, and that is factory edge. Still paperbook paper-slicing sharp. Do you think that having it at just 30° is good enough when it needs to be sharpened, taking my everyday tasks in mind? I'm not chopping trees down with it. xD
 
I never have been able to get my recurve blade ZT-350 fully sharp once I started messing with it.
I was able to split a hair with it, but it doesn't cut well at all.
 
You must log in or register to reply here.
Back
Top