Cliff Stamp
BANNED
- Joined
- Oct 5, 1998
- Messages
- 17,562
Awhile back I compared a Sebenza in S30V at 58/59 HRC to a 1095 blade at 66 HRC on a few media, cardboard and plastics. The edge on the Sebenza would just buckle at low angles and thus its wear resistance never came into the situation as the edge just cracked off.
Recently I ran it against an O1 blade at 63.5 HRC, three trials cutting 1/8" ridged cardboard, on a slice through 2 cm of blade, edge retention was checked slicing light cord under set tension after a short interval (15 m) and a longer one (35 m).
I used a micro bevel set at 20 degrees to vastly lower the effect of the higher strength of the O1 blade, as I wanted to examine mainly wear resistance. The first round had both edges recut at 3-5 degrees per side, then a light microbevel applied finishing on the fine Spyderco rods. The micro bevel was barely visible, <0.05 mm wide.
After the first short round the Sebenza about half as sharp as the O1 blade. Under mag and the entire microbevel had cracked off in certain sections. While the angle was high enough for strength, the underlying primary edge didn't have the necessary strength.
Next trial I set the secondary bevel about 0.1 mm wide. After the short interval both blades wer cutting similar, however after the long interval the Sebenza was again well behind and again sections of the edge were just broke away, enough to be seen by eye.
This has a massive effect on resharpening, the Sebenza doesn't respond to a steel with the edge broken off, and it takes much more honing as you have to regrind the entire edge, about 10:1 in favor of the O1 blade.
As a final trial, the secondary edge was over 0.15 mm wide. I also got sloppy on the O1 honing and it was only about 75% as sharp as it could be but ran the comparison anyway as I was mainly curious about the Sebenza.
Again the blades held well in the short interval, and after the long interval they were close, the O1 was still ahead, but only by a small amount, <25%, and the Sebenza's edge had only cracked in a few places. Note again though the O1 had a less than optimal initial edge.
As the work continued the blades would move apart as once an edge cracks it piles up stress there and it continues cracking faster. I have some more work planned when I have more cardboard and other stuff to cut to see how they compare if I set heavy micro-bevels, enough so the edge doesn't buckle. I would guess 0.2 mm wide should be enough for cardboard, plastics might need more.
I am not sure in the above how much of it is tensile strength or grain and carbide structure. The primary edge at 3-5 degrees leaves it very thin, if there are large aggregaties they might not be stable there regardless of the hardness.
-Cliff
Recently I ran it against an O1 blade at 63.5 HRC, three trials cutting 1/8" ridged cardboard, on a slice through 2 cm of blade, edge retention was checked slicing light cord under set tension after a short interval (15 m) and a longer one (35 m).
I used a micro bevel set at 20 degrees to vastly lower the effect of the higher strength of the O1 blade, as I wanted to examine mainly wear resistance. The first round had both edges recut at 3-5 degrees per side, then a light microbevel applied finishing on the fine Spyderco rods. The micro bevel was barely visible, <0.05 mm wide.
After the first short round the Sebenza about half as sharp as the O1 blade. Under mag and the entire microbevel had cracked off in certain sections. While the angle was high enough for strength, the underlying primary edge didn't have the necessary strength.
Next trial I set the secondary bevel about 0.1 mm wide. After the short interval both blades wer cutting similar, however after the long interval the Sebenza was again well behind and again sections of the edge were just broke away, enough to be seen by eye.
This has a massive effect on resharpening, the Sebenza doesn't respond to a steel with the edge broken off, and it takes much more honing as you have to regrind the entire edge, about 10:1 in favor of the O1 blade.
As a final trial, the secondary edge was over 0.15 mm wide. I also got sloppy on the O1 honing and it was only about 75% as sharp as it could be but ran the comparison anyway as I was mainly curious about the Sebenza.
Again the blades held well in the short interval, and after the long interval they were close, the O1 was still ahead, but only by a small amount, <25%, and the Sebenza's edge had only cracked in a few places. Note again though the O1 had a less than optimal initial edge.
As the work continued the blades would move apart as once an edge cracks it piles up stress there and it continues cracking faster. I have some more work planned when I have more cardboard and other stuff to cut to see how they compare if I set heavy micro-bevels, enough so the edge doesn't buckle. I would guess 0.2 mm wide should be enough for cardboard, plastics might need more.
I am not sure in the above how much of it is tensile strength or grain and carbide structure. The primary edge at 3-5 degrees leaves it very thin, if there are large aggregaties they might not be stable there regardless of the hardness.
-Cliff
