too thin of an angle?

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wicked1

Joined
Sep 1, 2004
Messages
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I just got a swamprat bandicoot and it was used and dull as hell so out comes the edge pro. I decided to try to sharpen it at 15 degree bevel with a 20 degree microbevel. I am having a real hard time with the burr coming off smoothly. The knife is definately sharp but looking at it on my microscope you can see some metal particles of the burr left behind. I am using the 600 stone with no water and no pressure 2 passes trying to get it perfect but no go. I just stropped it for a few passes on my strop and now it looks pretty good unless I zoom in to 100X then a few jaggies still. Is this too thin of an angle for this steel? My other swamp rats are sharpened at 20 degrees and 25 degree microbevel and the edge is beautiful evem at 100X zoom. This knife is definately out slicing them though. Push cutting newsprint is no problem nor is popping hair.Suggestions? I could try the 3000 grit tapes I have but I wanted it smooth at 600 first. I think I am becoming a little obsessed with my sharpening since I got a microscope. Used to drag it on PVC pipe if it didnt slip it was good to go. Now I look like a doctor doing surgery on my blade.:cool: Whats your take I figure I could go down to 10 degree primary on SR101 but havent tried yet.
 
It should handle 15/20 fine. It sounds like there is weakened metal left on the edge, or the coarse abrasive scratches are not completely obliterated, which is usually indicative of the relief grind not going all the way to the edge.

-Cliff
 
IMO - lap your stones to put the bite back into them.

Remove the burr before changing stones - your blade should be press cutting paper after the 180 / MF stone (with a little practice). Every blade should be coming off the 220 stone with a WOW edge. Remember to SWEEP off the burrs with good horizontal travel in your final strokes.

Try slice cutting folded bond paper (photocopy or printer paper) before the last few passes with a stone - I believe this to helps to distort "alined" burrs and make them easier to cut off with the stone.

Make smooth slicing strokes from heel to tip, feeling for rough spots. I'll cut a normal sheet into 1/4" strips before finishing with the 220 stone, then half sheet before 320 is finished, half sheet before the 600's final sweeps.

Once you feel an good-looking alined-burr edge turn after a dozen strips - going from smooth and sharp to draggy and gritty - you'll make edge stressing a regular part of your sharpening routine. I only use light cutting medium because I want to cut off the burr with a stone, not crack it off with a (eg) wooden block.

Works for me!

MAT
 
bbcmat said:
Try slice cutting folded bond paper (photocopy or printer paper) before the last few passes with a stone - I believe this to helps to distort "alined" burrs and make them easier to cut off with the stone.

...

I only use light cutting medium because I want to cut off the burr with a stone, not crack it off with a (eg) wooden block.
Click to expand...

That is a very insightful idea.

-Cliff
 
I reground my Bandicoot to 10 per side recently, with my microbevel at whatever I happen to be holding it at, probably 15 per side. Works greatl
 
arrg I still am having problems with this knife. This is the only one that has given me issues. I just reprofiled it to 10 degrees and cant seem to get it sharp for the life of me. I cant feel a burr at all on the bandicoot at 10 degrees. Even under the scope it appears the metal doesnt burr just flakes off or rolls. Wil keep trying the rest of the day.
 
Well I just said hell with it and raised the angle to 15 degrees and started at 220 and then I felt the burr. So I continued till it push cut and shaved. I just finished progressing upto the 600 grit stone. It is sharp now but why couldnt I feel a burr at 10 degrees? BTW Even at this 15 degree microbevel is slices great.
 
Also I ended up dulling the point hardcore but I will worry about that next time I sharpen it. I swear I am about to send this knife to someone to have sharpened properly at 10 degrees so I can see it myself what it should look like. Oh well.
 
If you can't form an edge at acute angles it typically means the steel is too coarse. It should not be the case with that steel. I would use it for awhile and try again later on to see if you can get a stable edge at ten degrees. Note generally with applying a microbevel you con't need to go very coarse because you are honing a very small strip of metal so you can make huge jumps in grits.

-Cliff
 
Cliff, I am also having problems with one knife at 10 degrees.

My S30V Leek sharpened at 10 degrees dulls VERY easily. I had it hair popping sharp - shaving both ways no problem.

I used a DMT xtra coarse stone with a jig as you recommended. I then put a substantial microbevel on with a sharpmaker at 15 degrees. After finishing with light strokes it got scary sharp, but only lasted one cutting job - a clear plastic memory card case. It would not come close to shaving afterwards.

I did rush the job a little and left the main bevel finished with high grit from the DMT stone. I did not think this would be a problem because I would polish out the scratches using a fine Sharpmaker ceramic when applying the microbevel.

What do you think happened?
 
CMSpeedy said:
I did rush the job a little and left the main bevel finished with high grit from the DMT stone.
Click to expand...

Generally this isn't an issue because the microbevel is what does the cutting on most media. Some people have had problems with burr formation going from x-coarse to high finishes but I have jumped massively and seen no issues. I usually grind at x-coarse DMT, use maybe 1-2 passes on 600 DMT to rough form the micro and do a 5x5 pattern (five per side, then fiver per side alternating each pass) to form the micro on a 1200 DMT.

What do you think happened?
Click to expand...

The edge chipped off, or the hardness is too low, both are known problems with S30V. Though they are usually spec'ed at 60 HRC, they have been reported as low as 55 when people have had them rehardened. This means they are actually softer than the steel in the Swiss Army knives.

Anyone who tells you that more than 15 degrees is needed to cut thin plastic needs a new defination of steel. This assumes of course you were slicing the case and not doing something like stabbing the blade into it and twisting it violently and spastically as this will load the edge laterally and will blunt it fairly fast.

If this is the first time you have sharpened the knife it isn't unusal that the edge retention is horrible. In many cases initial edges are poor as the steel is damaged in the edge. After several resharpenings the edge often improves. Often it doesn't as well. If that is the case you return it for a refund.

If you have to do something absurd like increase the profile to 15/20 so it can cut light plastic and not chip/roll then you have pretty much lost any benefits that would come from a "superior" steel.

-Cliff
 
To be honest after honing several knives lately. The S30V in the Leek makes a distinctively different sound than my S30V Spyderco's. The spydercos definately feel harder and take much longer to hone. Maybe Kershaw is not hardening them as well as spyderco as I have a Native at similar specs with no problems.

To be perfectly honest the 440A Leek gets sharper and holds a very good edge. I'm sure it will not hold an edge like the S30V, but it's acceptable.

I can put a crazy edge on the 440A, is it a finer grain steel?
 
:thumbup: I finally got it. I sat around here and it was just eating me up that I couldnt get the edge I wanted. So I started at it again. I did the main bevel at 10 degrees and took it to 1000 grit polish and I was impressed so I added the 15 degree microbevel at 600 grit then polished to 1000 grit then stropped it on paper after the edge was scary sharp finally.I got the tip back too! Now the problems I had was my 220 stone for my edge pro came unglued on me even though its new :grumpy: and my 120 stone crumbled to pieces on the reprofiling :grumpy: I have only reprofiled 3 knives on the 120 before it was gone. Now I know what to stock up on. The suction cups kept coming off the counter tonight too for some reason. I cleaned them with alcohol and the counter to make sure they were clean. Guess I need new suction cups. Sharpening this one friggin knife cost me about 20 bucks in materials and 5-7 hours of time. Oh well its a great hobby. This is now my sharpest knife I have ever had. Went through a cardboard shipping box like butter its own weight pushing through it. I had never seen that before. Awesome. :thumbup: Thanks for the tips everyone. I will keep stropping this knife everyday along with my straight razors when I shave to keep it this sharp.
<excitement of a giddy schoolkid here>
:D
 
Wicked1 I just went throught the same thing as you with the Edgepro. While it is an awesome tool I will never use it again for a major reprofile on a knife with good steel. You will be buying bunches of coarse stone if you take this route.

After wearing my 120 out after only 5 knives I came here and asked what to do. Cliff suggested that I get a DMT Xtra Coarse stone for major reprofile jobs. I bought one the next day and am very happy with it. I use a jig to ensure an accurate angle.

At $30 I'm sure it will save me money in the long run. I have been rough shaping edges on this stone and then refining them to perfection on my Edgepro. This system is working great for me.

Just my .02 from my very recent similar experience.
 
that sounds like a good idea. What do you mean by using a jig btw? I guess I could do the cut a block of wood at an angle of say 15 degrees and mount the benchstone to it. Kinda like the sharpmaker type sharpening but with the DMT stone. They had belt sanders on sale for $38 the other day too I was looking at it. 1" wide vertical. I am kinda hesitant to use one as I am afraid of ruining the temper of the steel but I see one finding a home in my house soon anyway. I dont know why my 220 stone came unglued from the base. That really irritated me. What kinda glue is recomended to put them back on? I was thinking epoxy.
 
I saw info on how to do it somewhere. I think it's on the edgepro site or here. Try a search. You can actually buy the stones separate from the metal and glue them yourself. It should save some money, but I prefer to buy them from Edgepro.

Perhaps I should have specified on the Jig. What I am calling a jig is a wooden block I placed under the back of the stone until I got a 10 degree angle. I then hold the blade flat to my table. I like doing it this way because it works with all size knives. It would be hard to rig up a jig on a narrow bladed pocket knife. It is nice to have the edgepro handy as you can use it to check your angles accuracy. Once I get a little better I may try to lay the stone flat, use more feel, and go totally freehand. I'm still learning though.
 
CMSpeedy,
I was having an extremely rough time getting an edge that will cut free hanging hair on my friend's S30V Leek. To make matters worse, after I got the edge to that point - the very next day, the edge would no longer cut free hanging hair. I had not cut a thing with the knife. After a while, I realized what was happening. The edge of my friend's leek was hitting the backspacer along most of its edge whenever the knife was closed. It seems to be designed this way since there is no stop pin. As I was sharpening I would move to the restroom to check the edge and on the way to the restroom I would close the knife, instantly dulling the edge. This may be happening with you knife.
 
CMSpeedy said:
I can put a crazy edge on the 440A, is it a finer grain steel?
Click to expand...

It has a lower amount of primary carbides than the common high wear steels like 440C/ATS-34. This does make it possible to obtain a higher push cutting sharpness. The problem with the high wear steels is that you also need an increased hardness to maintain ease of sharpening. If you do end up with one of the high wear steels which was ran soft they are very difficult to sharpen well. They still resist grinding very strong but deform very easily. You essentially get the worst of both aspects as it becomes difficult to press hard enough to cut them well and not deform the edge and burr it.

wicked1 said:
...my 220 stone for my edge pro came unglued on me even though its new
Click to expand...

Contact Ben Dale, that's defective, though if you dry it out you should be able to epoxy it back on.

-Cliff
 
Buy your stones from EdgePro or you can get 1" width stones from various suppliers of abrasives for Tool and Die makers. From EdgePro you know what you are getting consistency wise however. Buying unmounted stones from EdgePro you save 50% of the cost and you're reusing your blanks 3M spray adhesive 777 works great. Never use epoxy it's a freaking bear to get off the stone blank.

You can switch to coarse diamond from DMT just specify that you want the 1"X6" without a pedestal. Then glue that to your stone blank. Honestly I have not yet seen the advantage. Though I have only owned for a month and haven't used it all that much. It doesn't cut as fast as the 120 from EdgePro and leaves some pretty horrific gouges, though I'm told after it's been used a bunch of times this subsides. I haven't seen it yet, maybe I have to use it more. At 7$ for a stone if I get 5 knives out of it I'm fine with that.

I have on order a 8" XX Coarse Dia-Sharp for freehand reprofiling, from all I've heard it's almost as fast as a belt sander.

It has seemed to me for some time now that a LOT of suppliers are running on the soft side on their hardness. Where they are advertizing/stating high 50's low 60's RC in point of fact they are coming out at mid 50's at best and often in the low end of 50's. That's by my feel not an actual test. Blades are just not performing as they should even many higher end blades are coming out way too soft. Why pay for high end steel that's not hardened properly. The hardness is required to take advantage of the steel and without it some are impossible to get sharp. (As Cliff has stated) I think we as consumers need to step back and bitch a bit more and demand they live up to what the manufacturer is saying. My opinion only of course yours may differ and your mileage may vary.
 
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