Will that bloody thing ever get sharp ?!

M

Mokk

Joined
Sep 5, 2003
Messages
19
Trying to sharpen BM 710HS on spyderco triangle sharpmaker... am i doing something wrong ? it just dosnt gets sharper, specialy in the curve area near handle, looks kinda strange to me, i know that M2 steel is hardened to 61 RC, but ceramics are harder then that, some say that 440v is steel that hard to sharpen, but i had no problem putting wicked edge on it just in couple minutes with triangle sharpmaker,
i think that 710hs comes from factory sharpened on 36 degrees , maybe i should try 30 degrees angle on sharpmaker ?
 
If you are sharpening at a more acute angle, it will take forever to get it sharp on the Sharpmaker. Use a marker to outline the edge and see where the abrasive it hitting the bevel. If it is above the edge you need to hog the edge down with a coarse stone, this can be done fairly sloppy as it is just shaping. Once the bevel has been lowered it should be able to be honed on the Sharpmaker in a couple of minutes. More details in Joe Talmadges Sharpening FAQ.

-Cliff
 
Ceramics don't cut very fast so it would take forever to change the bevel on an M2 alloy blade. If you want to merely sharpen the edge region you need to go to a larger angle than the original. If it had a 36 degree included angle you would need to use 40 to 50 degrees (20-25 degrees per side) to touch up the edge. It might take hours to change the edge to 30 degrees included angle using a sharpmaker.

For speed I would work exclusively with the corners of the brown (medium grit) rods until I started feeling edge improvement. I would use the higher (numerical) angle setting (closer to horizontal). Clean the rods with sink scouring powder and water periodically.

If you don't like the result when you are done you may need to lower the angle of your edge using a faster cutting hone. For a recurved blade you want something round or narrow to reach the inside (concave) part of the curve. Try clipping strips of 120 grit Wet or Dry paper over your sharpmaker rods. In this case use the paper over the flats when you hone. I would use this to produce a back bevel of 15 degrees per side (30 degree included angle). To finish off repeat this paper honing using 220, 400, and 600 grit paper then use the brown and white ceramic rods directly.

M2 is tough stuff.
 
Yep, that M2 is some tough to sharpen stuff. I learned that the hard way, with those old Gerber bird and trout knives. Those knives would stay sharp almost forever, but were a real bear to get an edge on.
 
my suggestion is to go get the Gerber diamond "pen" hone.. it costs about 8 bucks you get it at Walmart... then carefully sharpen the bevel down. I have several sharpening systems. When I have a bevel problem I get my lansky out. I duct taped the gerber "pen" hone to a small piece of alum rod. Then using my lansky to keep the bevels the same I hone the edge dowm. All I am doing is reshaping the edge. Then its just a matter of doing the final sharpening on my sharpmaker. I hae done this on several knives and it has worked every time
Jack
 
Originally posted by Cliff Stamp
If you are sharpening at a more acute angle, it will take forever to get it sharp on the Sharpmaker. Use a marker to outline the edge and see where the abrasive it hitting the bevel.
Click to expand...

Cliff is right on with this -
my Benchmade 710 came with a very obtuse edge - so using a SharpMaker would have been honing away at the shoulder between the bevel and the blade face and NOT the actual cutting edge at all.

My BM 710 was a very early sample (Feb/1999), but it sounds as if some BM 710's are still coming with not very sharp edges (I recall Joe Talmadge had similar problems from a BM 710 of similar vintage) BM 710 thread at rec.knives

and
Joe Talmadge's post at rec.knives
 
You already got responses from experts here, I´ll just add that you may want to get a good magnifying glass and look at the edge carefully, see if you are just working on the base of the edge and how the bevels are forming, this along with the ink outline from a marker as Cliff suggests should give you a good idea of what is happening.
 
Benchmade has LifeSharp service and will sharpen it for free. Maybe they will give you less of an angle on the re-sharpening and save you some trouble. Give them a call.
 
I'm a big fan of the marker trick. If you like the soothing trance of repetitive motion, you can and will succeed (most of the way, at least) using the Sharpmaker. For tougher steels (M2, D2, S30V), I just mark up the edge and use alternating strokes with an arbitrarily high number.

On bellied blades, such as the 710HS, I end the stroke with the tip pointing almost straight down, moving the knife from parallel to the ground to nearly perpendicular in a semi-circular motion. Also, I start with the belly-to-tip first with 150 or 300 alternating strokes on the flats of the diamonds or the mediums and then 150 or 300 alternating strokes from choil to tip. My 710HS still has a ways to go before the edge near the tip is sharpened at 30 degrees, but I've managed to get a 30 degree edge everywhere on the blade that pops arm hair using just the medium hones. This was after setting a 40 degree micro-bevel, so there was a bit of stock removal...

If you don't like taking that much time, or if you can't, there's always the corner of a coarse benchstone or taping 60 AO sandpaper to the Sharpmaker hones.
 
Thank you all for response, as i understood i will aventualy get sharp edge on sharpmaker, if i got couple a weeks to spare, guess that what ill do. its not easy to find good sharpening equipment in Israel, and if you do it costs three times more then is US, then again i spend to much money on knifes lately so if i wanna go to college ill have to calm down a little bit. Now about life sharp service, well its gonna cost me about 30$ to ship it to benchmade and another 30 to get it back ,so its just not worth it. After couple hundreds strokes on each side part of the blade (from tip to the middle) became razor sharp, hope that recurve will give up to...
 
Just got my BM 710HS today it's pretty much perfect ! Had some doubts after reading some of the other posts about edge angles & blade play, but wanted the knife for the M2 & Axis lock. They have done a great job on the blade lockup, no play at all. Have'nt measured the angles that the blade is ground to, but it easily cleared the sharpmaker at 40 degrees & allowed me to put the microbevel on easily. After that, just strop it for a sticky sharp edge. Mine cuts hair without touching the skin. Took about 5 minutes. It's got the brass bushings so I'm guessing this is one of the later models. Sorry to hear about your problems, but those guys are right about reprofiling the blade using coarse sandpaper taped to the sharpmaker. You'll get consistent results & it will speed things up dramatically. Check your work with a magnifying glass & marker. You'll be fine :p
 
Just wanted to add one thing on the angles from the factory. BM has stated many times that all thier sharpening is done BY HAND. That means that there is no preset angle for all of thier knives.

I have a more recent 710HS which has a pretty good edge on it. I'm using it as is for now until I have some time to play with the sharpmaker. I also need to get new rods as the ones I have are defective. :( They have small chips/indents on them which tend to chip up an edge real quick.
 
Lots of good advice there, Mokk. A couple of ideas from my own experience:

1) The Sharpmaker is great but you don't want to go off the edge of the rods and round the tip of your blade. Also, you've already found you're not getting every part of the blade as well as the rest.

To get around these problems, do that part by hand. Just hold one rod like a sharpening steel and buff away at the problem area. It won't take as long as by laboriously slicing up and down the vee.

2) Unless you get the diamond rods (which cost more than the Sharpmaker itself!) reprofiling will take time. You can get a small diamond stone, but I recommend a round diamond rod like this EZE-LAP Diamond Sharpener. You just have to line your angles up by eye, which the marker trick will help you to do.

3) One more trick. A convex edge is strong and sharp but harder to maintain. You can get a 'poor man's convex edge' by sharpening the cutting edge to 40 degrees and then going back and sharpening the blade to 30 degrees as well. This won't touch the edge itself, but it will narrow the blade just above the edge, giving you a stepped version of the smoothly curved convex.
 
Well, i got some realy good advises here, Slices inspired me to give sharpmaker another try, and if it doesnt works, probably my next purchase is gonna be diamond rods...
 
"by "brass bushings" do you mean yellow disks"

Mokk, yes, "brass" is 'pliz', similar to 'nehoshet'.
 
Well after several thousands strokes on medium rod, i final gave it 20 degree bevel.
I wonder why benchmade keeps sharpening they knifes by hand, i just dont find it very exciting to open box with your new knife , without knowing what horrors you gonna find inside...
Then again for a real knifenut its just another chalenge to overcome.
By the way i do have "nehoshet" disks in my 710, so even if it is one of the "later models" as Slices called it, it still had very ugly edge, unevenly sharpening on both sides and different parts of blade.
 
I was'nt aware that they did their sharpening by hand ! That explains why so many of their knives need reprofiling right out of the box. Seems very unprofessional.. Anyway, it sounds like you have the brass spacer bushings too, so it must be a newer model. My Gerber Gator fixed blade came with very steep grind , right out of the box, had to reprofile it right away to get it working with the sharpmaker. If you're going to do much knife sharpening, I can't recommend the EdgePro Apex sharpener highly enough ! they're expensive , but worth it. Very fast to reprofile ANY blade & infinitly variable sharpening angles. You just mark the edge with a marker , then light strokes to see where you're cutting, & you can match the existing edge on any blade. If you're interested , check em out here.
http://business.gorge.net/edgepro/
Cya
 
I though BM's claim to sharpen by hand just meant that it was done by a person as opposed to totally by a machine. You can sharpen knives to preset angles by hand using a number of machines.
 
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