Troubles - Super Steels or Blade Types?

cziv

cziv

Joined
Nov 24, 2005
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Hi,

I've been having an impossible time trying to bring 2 of my Benchmade knives to very sharp. I've used the Sharpmaker on them, tried micro-bevels, then sanded the shoulders on a mousepad, by stropping them and used the leather typ of strop with Green compound but nothing keeps them really sharp.

Went cak and put straight 30* incluseive edges on them again and continue to leather strop them daily.

The knives will make one or maybe two sweeping cuts through copy paper and then they get hung and tear the paper or bend it to a squeaking halt! :mad:

The knives are: a BM 940 Osborne with the reverse tanto point in S30V steel and BM 710 in D2 steel with that attractive but difficult recurved blade.

My other Benchmades are very sharp but these two never were and I haven't been able to improve on them.

Is it me, the blade steels or the blade configurations.

Maybe a mix of all? Not to say they aren't sharp, they'ed cut about anything.

Any ideas guys? :confused:
 
Greetings CZIV: I have experienced the one or two sweeping cuts through copy paper and then tearing or ripping to a halt . I have found that it usually indicates a very fine burr or wire edge. Cutting into an old leather belt or even a piece of cardboard at 90 degrees to the blade edge usually removes the burr. To test, try steeling the edge lightly once it starts to hang up in the copier paper. If it begins cutting smoothly again, it is a burr. OldDude1
 
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OldDude1 said:
Greetings CZIV: I have experienced the one or two sweeping cuts through copy paper and then tearing or ripping to a halt . I have found that it usually indicates a very fine burr or wire edge. Cutting into an old leather belt or even a piece of cardboard at 90 degrees to the blade edge usually removes the burr. To test, try steeling the edge lightly once it starts to hang up in the copier paper. If it begins cutting smoothly again, it is a burr. Some hig OldDude1
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First, D-2 and S30V are wonderful steels, but most definitely NOT "super steels."

They aren't hard to sharpen at all with good stones, or an Edge-Pro (www.edgeproinc.com) but I imagine they would be almost impossible to really sharpen or re-bevel with a Sharpmaker. The Sharpmaker is a wonderful tool for maintaining an already sharp knife with a 15 or 20 degree existing bevel.

If you don't wish to spend the money on better equipment, get them professionaly sharpened, and specify a 15 degree bevel, then maintain that shaving sharp edge with the Sharpmaker.
 
OldDude1,

I have heard that advice before but didn't think I had a burr - but I did.

I took each problem knife and cut into a cardboard shipping box two nice deep cuts with each and what do you know, there's a great improvement - not like a razor but no hang-up or tears!

I thought it was the steel and maybe to some degree it is. My RAT Izula cuts like a banshee and makes the higher priced BM's look like $5 blades.

Now my Griptilians don't have this problem 154CM steel. Very sharp, I've spilled blood on them more than once when fooling around with them. :eek:

I appreciate your post.
 
If you have a burr then you need to remove it or as soon as you cut something somewhat hard it will fold over and be dull again.

I use the polishing wheel on my paper wheels to remove a stubborn burr but stropping should do it as well. Sometimes increasing the sharpening angle for a couple light strokes helps take it off as well. I'm sure others with more experience will chime in. A stubborn burr that doesn't want to come off can be very frustrating!
 
D-2 and S30V most definitely NOT "super steels."
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I was in error, I thought they were very good, premium steels??

The Sharpmaker is a wonderful tool for maintaining an already sharp knife with a 15 or 20 degree existing bevel.
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That's what I'm using, 30* setting, on an already sharp knife. I put marker on the blades and despite someone mentioning that they were factory set at 40*, the 30* setting is what removes the marker from the edge.

I'm also wondering if my Sharpmaker is a bad unit. I've owned it for a couple of months and one side is very loose and sloppy, the rods are loose in the base on one side, tilt even more at the slightest pressure and don't appear to be trued to the base but slightly angled so that I have to shift my knife to get it into full contact with the rod.

The other side is very snug, top to bottom and holds the rod squarely & true, against the blade - when seated behind it. Unlike the sloppy side described above.

And it might not have any impact on my sharpening issues either?
 
Give the stones a good cleaning before trying anything else. The sharpmaker stoned load up pretty quickly and need a fresh surface to keep cutting. I throw mine in the dishwasher.

Have you tried the 40 degree setting? I don't use the Sharpmaker for sharpening the full bevel anymore. Particularly on those 2 steels, they will not remove metal fast enough for my taste if used on the whole bevel. Also, I have not found cutting into anything soft like a board or cardboard to remove a burr. It will bend it over and maybe break it off eventually, but won't wear it off. Try cutting VERY lightly into the brown stones at 90 degrees once or twice, then go from there. Or try using much higher angles, like with the blade parallel to the opposite stone, for a total of 60 or 80 degrees, depending on the setting. Do this VERY lightly as well, for 1 or 2 strokes per side at most, then go back to regular angles, or slightly increased by a couple of degrees.
 
Me2 is of course quite right. The 90 degree cutting into leather or cardboard will only inconsistently remove the thinnest of burs. Me2's method is much better. If you can not or do not wish to spend more money on sharpening equipment at this time, the Sharpmaker can be used to get the job done. If the Sharpie marker line is being TOTALLY removed at the very cutting edge, then, the SharpMaker rods are doing their job regardless of the observed sloppiness in their seating within the base. One rod angle may be off by one or two degrees but as long as both bevels meet at the cutting edge the knife will be sharp. Within the last year, I have reprofiled two Benchmade 940's (S30v), two small Sebenzas (S30v) and one Benchmade 710 in D2. All were taken back to a 30 degree bevel. All using the Sharpmaker. It was VERY VERY time consumptive but far from "almost impossible". I have and use both a GATCO Diamond Hone System and an EdgePro. They are much quicker for reprofiling but are perhaps not the best for recurve blades. The Edgepro ceramic rod edges seem to be better suited to that task. IMO "Super Steel" is a descriptive term that changes each time a new "Improved" alloy or alloying process is discovered or perfected. The newest steel suddenly becomes "Super Steel. I believe D-2 steel dates from about World War One. S30v is perhaps the first steel engineered primarily for cutlery manufacture. They are both high quality knife steels as used by Benchmade. They may not be Super but with proper heat treat they do what they were designed to do. OldDude1
 
Thanks guys,

It has to be my technique. I'll try the higher angle and removing of burr with scraping lightly. I've done that before but will try again.

Maybe I expect too much? I find that Spyderco more than BM are crazy sharp every time out of the box. As are CS (Voyagers anyway is what I have 2 of).

I can't get the BM 940 or 710 models 1/2 as sharp. But I'm going to stay at it until I do. :)
 
cziv said:
I was in error, I thought they were very good, premium steels??
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I would call them "super steels." D2 is a hell of an edge holder. S30V is also a good edge holder with very good resistance to corrosion.

In my opinion, 154CM and VG-10 are the entry level "super steels." Anything with better edge holding I consider a super steel (ok, and H1 for its rust proof ability.)
 
OldDude1,

I have no doubt that a GATCO Diamond Hone System and an EdgePro would make short work of that.

However I have what I have. The diamond rod corners will make short work of putting a 30* bevel on either knife, including wrapping right into those recurves.

My problem is that I always try to convex them which may be what's hurting my for these 2.

I did the technique that "me2" suggested - grinding off any burr and just put a straight 30* on them and lightly stropped with BR green compound on a shaved suede leather covered strop block.

They're working a little better now - in fact they're quite sharp, just not "hair-popping." I have to scrape a bit to shave hair on my arm.

Good enough for me! :thumbup:
 
Not sure but this may because of micro scale burr.
Remaining burr on the very cutting edge does some small amount of cutting job
but eventually destroyed and after that a ruined cutting edge remains.

This occurs if too much force was put on the edge at the final stage of sharpening.

Just my personal experience and guessing, though.
 
I ground the recurve out of my BM 710 (w CM154 blade). This makes it sharpenable on flat stones. I now sharpen it and my 940s and 943s on propped up large stones which duplicate the Sharpmaker angles. I do the heavy lifting (grinding) on the large stones (2 1/2X 11") and finish up on the sharpmaker. The other BM blades are S30V, D2, and Stamascus. This setup also works on S90V, S60V, Stellite 6K, Stellite 6BH (Talonite), ZDP 189, Cera Titan, Beta Ti, BG42, etc.
 
THG said:
I would call them "super steels." D2 is a hell of an edge holder. S30V is also a good edge holder with very good resistance to corrosion.

In my opinion, 154CM and VG-10 are the entry level "super steels." Anything with better edge holding I consider a super steel (ok, and H1 for its rust proof ability.)
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I would too. If S30V is not then neither is BG42 and others in this class .
That means the super steel class must be very narrow to some . Like ZDP 189, S60V, S90V and some of these . DM
 
tiguy7 said:
I ground the recurve out of my BM 710 (w CM154 blade). This makes it sharpenable on flat stones. I now sharpen it and my 940s and 943s on propped up large stones which duplicate the Sharpmaker angles. I do the heavy lifting (grinding) on the large stones (2 1/2X 11") and finish up on the sharpmaker. The other BM blades are S30V, D2, and Stamascus. This setup also works on S90V, S60V, Stellite 6K, Stellite 6BH (Talonite), ZDP 189, Cera Titan, Beta Ti, BG42, etc.
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How long did it take to remove the recurve?
 
Send it to Tom Veff, look him up in Oregon. Veff's Sharpening. He will put a mirror convex edge on it that is scalpel sharp, no really it is, for next to nothing. I sent my D2 710 to him and it came back retardedly sharp. . . For like 10 bucks. Thats the way to do it, D2 will hold an edge for a long time. He has sharpened everything from my folders to my Busses, and a couple of khukris too. they all came back flawlessly done in three days. He is that good.:thumbup:
 
To remove the recurve from the BM 710, I removed the blade from the knife and ground off the offending material on a belt grinder with a platen behind the 80 grit belt. I used a pail of water to keep the blade cool to the touch. The blade actually has a slight belly to it now. I then rebeveled the the handle end of the blade on the same grinder and finished up on the large Crystalon (Carborundum) Silicon carbide stones and a large India (Corundum) Aluminum oxide stone. The total time was less than an hour.
 
I guess it's a matter of perception.

I dearly love both D-2 and S30V.

But to me, true "super steels" start at S90V and CPM M-4. :p
 
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