Benchmade 940 on Sharpmaker.

[Django606]

Hi guys. I got a BM 940 and a Sharpmaker for my birthday on Friday.

I am completely impressed by the 940, and I definitely know what my next knife will be

It is super sharp, and I don't want it to get dull. From time to time I am going to touch it up on the Sharpmaker. I have a few questions before I mess up the scary sharp edge

-What angle is it ground to?

-Which stones should I start with when I go to touch it up? My guess is white, but I might be wrong.

-40* or 30*? I sharpened it very lightly on 40*, and then stropped it, and it seems sharper than when I first got it.

Thanks.

 

[tim8557]

Your safest bet would be to mark the beveled edge of the knife with some magic marker (it'll easily wipe off with rubbing alcohol). Then set the Sharpmaker up at 30 degrees and using the white flats gently run the blade down the stone as if you were sharpening it. Under a good light, and judging by your age, you won't need a magnifier, check to see where the marker was removed. If the marker is not removed to the edge, then the knife is gound to an edge greater than 30 degrees.

At that point, you can reprofile the bevel to 30 degrees on the Sharpmaker with the brown edges, but depending on the steel, could take a very, very, very long time.

For grins, clean the edge, reapply marker and try the above at the 40 degree setting. It should remove the marker to the edge and possibly the entire bevel meaning that the knife is set at 40 degrees. Most probably it is somewhere between 30 and 40 degrees. That being the case, you have built in relief and can just sharpen at 40 degrees.

 

[Django606]

The steel is 154 CM.

So would you reccommend checking it on 30 or 40 degrees first?

Also, I don't have the brown stones. I only have grey and white..I just got it Friday.

When I go to test it, don't actually sharpen it, just rub it down the rod perpendicular to the base?

If it is 40*, I want to keep it at 40, etc.

 

[tim8557]

That's a great steel and will be difficult to change the angle with a sharpmaker. There seems to be a difference in the way everyone "sees" the color of the rod, gray, brown, whatever. The "darker" rods are medium grit and the white are fine.

Personally, I would use the magic marker to again, determine the factory angle and use the rod angle that hits the edge. Then just always sharpen at that angle. If the factory angle is 40 degrees, you will never be able to sharpen to 30 degrees with the Sharpmaker (unless you have unlimited time and patience). You also better understand the principals of sharpening; angles, burrs, relief angles, etc.

I would first test it at 30 degrees. If you remove the marker to the edge then always sharpen at 30. If not, try 40 which should hit the edge and then keep it at 40.

Hopefully, I'm not confusing you even more but once you understand the principals, it is not that difficult. Buy a couple of cheap knives at a flea sale or something and practice on them first, then the Benchmade.

Good luck.

 

[TOB9595]

The 940 was among my fav EDCs. Like so many it's long traded
But the advice above is valid.
Put the magic marker on the "shiny" ground edge both sides of the blade. Then try it on the 30 degree lightly at first. Then try the other side on the 40.
The Sharpmaker is superb for edge maintenance.
I always used the white rods on 40 for the 940.

Since you're fairly new to all this a visual representation of what the sharpmaker is taking off is important.

I also STRONGLY advise you to get a copy of Juranich's Razoredge Book of Sharpening.
It was only a few years ago that I came across this book and it made all the stuff I read for 40 years come to clarity.
Let us know what and how you do.
Tom

 

[GWO]

I would like to jump in since I seem to be in the same boat. New blade and new Sharpmaker. If using the 40 just sharpens the edge, then you have a blade with a relief angle. Right? A blade with a relief angle gets sharper, or is easier to sharpen?
If 30 degrees sharpens the entire edge, then the blade has no relief angle. Right? It just has one 30 degree angle? In this case, would it be beneficial or recommended to reprofile to 30, then add a relief angle of 40 to the very edge? I think I get it, but the more I read the "confuser" I get. Thanks for trying to unmuddy the waters.

 

[tim8557]

I would like to jump in since I seem to be in the same boat. New blade and new Sharpmaker. If using the 40 just sharpens the edge, then you have a blade with a relief angle. Right? A blade with a relief angle gets sharper, or is easier to sharpen?
If 30 degrees sharpens the entire edge, then the blade has no relief angle. Right? It just has one 30 degree angle? In this case, would it be beneficial or recommended to reprofile to 30, then add a relief angle of 40 to the very edge? I think I get it, but the more I read the "confuser" I get. Thanks for trying to unmuddy the waters.

Welcome to the "world of Confused Sharpening".

I believe that you are correct in that the relief angle is always less than the primary edge angle. I generally use my Edge Pro to set a relief angle at less than 30 degrees and then the primary (cutting) edge at 30. That makes it easier to do quick touchups with the Sharpmaker set at 30.