Cliff Stamp
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- Joined
- Oct 5, 1998
- Messages
- 17,562
Recently I have been doing some work with a few Olfa blades, these are the commonly used snap-off utility cutters. The first thing I wanted to do was check was the claims made about the Ultra-Max blades vs the normal ones. There are two promoted advantages. The Ultra-Max blades are supposed to be 25% sharper and have 5 times the edge retention.
Checking the edges on thread, the sharpness different was significant and easily noticed. The normal blades scored 90 +/- 4 g, with the Ultra max blades only requiring 75 +/- 5 g. Fives blades were used for each type, and done both for the normal cutters and the heavy duty one (twenty blades in all, five cuts made for each blade). No significant difference was noted between the same blade type on the two different cutters (normal vs heavy duty).
Can this difference be seen in normal use? Yes, it is large enough to notice readily for fine cutting. It is also very consistent from blade to blade. How does it compared to high end production blades? Well even the sharpest production knives like Spyderco and Cold Steel can't even reach the level of sharpness of the normal blades. Those production blades typically score ~100-120 g. This will for example allow a smooth shaving, but the normal Olfa blades are sharper than that and will catch hair readily above the skin.
What accounts for the difference in sharpness? Two factors. First off all, checking the edge under magnification, it is more uniform on the Ultra Max blades. Also, on the Ultra Max blades there is also a distinct difference in grit used between what abrasive was used to form the edge that you can see, and the tiny micro-bevel that actually does the cutting (~1/10 of a mm wide). The micro-bevel is more polished thus a higher grit was used. On the normal blades it looks like the micro-bevel is ground with the same abrasive that shaped the edge.
The second difference is that the Ultra-Max blades are ground at a different angle than the normal blades. You can see this by eye the difference is large enough in edge width (the stock thickness of the blades is the same 0.3 mm for the normal cutter, and 0.5 mm for the heavy duty cutter). Actually measuring this angle is difficult because the dimensions are so small. For the normal blades I would say the angle is 10.0 +/- 0.5 degrees, and only 7.0 +/- 0.5 degrees for the Ultra Max blades. The micro bevel is also about twice as wide on the Ultra-Max blades.
In regards to edge retention, I cut ~80 m of cardboard (1/8" ridged, cut across the ridges) with the normal cutter, using three blades of both types. The Ultra-Max ones did indeed showed a distinct advantage but it was small. The normal blades would start to tear the cardboard a little sooner, but the advantage was no where near five to one. The sharpness was also tested periodically by cutting light thread and poly, as well as shaving and cutting light paper. I have some more work to do to quantify this a little better, but the best I would put it would be two to one. I then did ~55 m of cardboard cutting (1/4" double ridged, cut across the ridges) with the heavy duty cutter (five blades of each type), and saw an even smaller advantage for the Ultra Max blades.
However on cutting hemp rope with the heavy duty cutter, a much larger difference was noted between the normal and Ultra-max blades. The Ultra-Max blades were far more aggressive, you would not need to measure anything to note the difference in slicing ability. Both could slice through 62 cuts without much difficulty. However the normal blades started to have a lot of difficulty after that. By the time 126 cuts were performed the Normal blades were sliding a lot and excessive force had to be used and you were approaching the point at which the blades are likely to break as they are flexing a lot during the cut. The Ultra-Max blades were far more aggressive and need far less force to do the cutting. I have more cutting to do to quantify the advantage, but the five to one in favor of the Ultra-Max blades seems realistic to me based on past cutting I have done.
The normal cutter could not be used to cut the hemp as the blades were too weak if you extended them out this far (~5 cm). These blades are actually designed to break, they periodically have grooves cut in them. When the point or leading section of blade goes dull, you just break it off and push out a fresh section. I broke off one of the normal blades slicing through the cardboard when I leaned too heavily. You can cut very thick cardboard with them (I did one run on the 1/4" material), you just have to be careful. The Heavy Duty blades handle cardboard without fault, and can also be used to cut ropes and whittle wood.
I also ran two blades against the Olfas in the cardboard cutting, an Opinel and Sub-Sniper. With both blades finely polished, they were outperformed significantly by the Olfas (more than 2:1). When the Sub-Sniper was finished with a 600 degree DMT rod, it blunted a bit faster in the beginning, but held its own in the end. It also has a ~10 degree edge bevel, it didn't come like that I reground it. I also used two cheap snap off blade holders alongside the Olfa models. The cheaper models were not as ergonomic, nor as secure, and offered lower cutting ability by not holding the blade as securely so it had much more play, and could be pulled out on the heavier tasks.
There are a few drawbacks with these knives compared to normal utility folders. First of all is the obviously low lateral strength. They are designed to break so even light prying (or stabbing) will break the blades. Secondly the blade shape is very limited, you only have a Wharncliff style. Third since the blades are retracted into the handle, cutting messy material can give you quite a task to clean out the handle. They do offer a very high sharpness and cutting ability though, and the lock mechanism can't be easily failed - you will just break the blade off. I also have the Ultra-Heavy duty model (0.7 mm thick), it is stiff and strong enough for any cuttig, even very heavy rope and thick wood. No batoning though I would assume. More to come as I work with them.
Link :
http://www.olfa.com/
-Cliff
Checking the edges on thread, the sharpness different was significant and easily noticed. The normal blades scored 90 +/- 4 g, with the Ultra max blades only requiring 75 +/- 5 g. Fives blades were used for each type, and done both for the normal cutters and the heavy duty one (twenty blades in all, five cuts made for each blade). No significant difference was noted between the same blade type on the two different cutters (normal vs heavy duty).
Can this difference be seen in normal use? Yes, it is large enough to notice readily for fine cutting. It is also very consistent from blade to blade. How does it compared to high end production blades? Well even the sharpest production knives like Spyderco and Cold Steel can't even reach the level of sharpness of the normal blades. Those production blades typically score ~100-120 g. This will for example allow a smooth shaving, but the normal Olfa blades are sharper than that and will catch hair readily above the skin.
What accounts for the difference in sharpness? Two factors. First off all, checking the edge under magnification, it is more uniform on the Ultra Max blades. Also, on the Ultra Max blades there is also a distinct difference in grit used between what abrasive was used to form the edge that you can see, and the tiny micro-bevel that actually does the cutting (~1/10 of a mm wide). The micro-bevel is more polished thus a higher grit was used. On the normal blades it looks like the micro-bevel is ground with the same abrasive that shaped the edge.
The second difference is that the Ultra-Max blades are ground at a different angle than the normal blades. You can see this by eye the difference is large enough in edge width (the stock thickness of the blades is the same 0.3 mm for the normal cutter, and 0.5 mm for the heavy duty cutter). Actually measuring this angle is difficult because the dimensions are so small. For the normal blades I would say the angle is 10.0 +/- 0.5 degrees, and only 7.0 +/- 0.5 degrees for the Ultra Max blades. The micro bevel is also about twice as wide on the Ultra-Max blades.
In regards to edge retention, I cut ~80 m of cardboard (1/8" ridged, cut across the ridges) with the normal cutter, using three blades of both types. The Ultra-Max ones did indeed showed a distinct advantage but it was small. The normal blades would start to tear the cardboard a little sooner, but the advantage was no where near five to one. The sharpness was also tested periodically by cutting light thread and poly, as well as shaving and cutting light paper. I have some more work to do to quantify this a little better, but the best I would put it would be two to one. I then did ~55 m of cardboard cutting (1/4" double ridged, cut across the ridges) with the heavy duty cutter (five blades of each type), and saw an even smaller advantage for the Ultra Max blades.
However on cutting hemp rope with the heavy duty cutter, a much larger difference was noted between the normal and Ultra-max blades. The Ultra-Max blades were far more aggressive, you would not need to measure anything to note the difference in slicing ability. Both could slice through 62 cuts without much difficulty. However the normal blades started to have a lot of difficulty after that. By the time 126 cuts were performed the Normal blades were sliding a lot and excessive force had to be used and you were approaching the point at which the blades are likely to break as they are flexing a lot during the cut. The Ultra-Max blades were far more aggressive and need far less force to do the cutting. I have more cutting to do to quantify the advantage, but the five to one in favor of the Ultra-Max blades seems realistic to me based on past cutting I have done.
The normal cutter could not be used to cut the hemp as the blades were too weak if you extended them out this far (~5 cm). These blades are actually designed to break, they periodically have grooves cut in them. When the point or leading section of blade goes dull, you just break it off and push out a fresh section. I broke off one of the normal blades slicing through the cardboard when I leaned too heavily. You can cut very thick cardboard with them (I did one run on the 1/4" material), you just have to be careful. The Heavy Duty blades handle cardboard without fault, and can also be used to cut ropes and whittle wood.
I also ran two blades against the Olfas in the cardboard cutting, an Opinel and Sub-Sniper. With both blades finely polished, they were outperformed significantly by the Olfas (more than 2:1). When the Sub-Sniper was finished with a 600 degree DMT rod, it blunted a bit faster in the beginning, but held its own in the end. It also has a ~10 degree edge bevel, it didn't come like that I reground it. I also used two cheap snap off blade holders alongside the Olfa models. The cheaper models were not as ergonomic, nor as secure, and offered lower cutting ability by not holding the blade as securely so it had much more play, and could be pulled out on the heavier tasks.
There are a few drawbacks with these knives compared to normal utility folders. First of all is the obviously low lateral strength. They are designed to break so even light prying (or stabbing) will break the blades. Secondly the blade shape is very limited, you only have a Wharncliff style. Third since the blades are retracted into the handle, cutting messy material can give you quite a task to clean out the handle. They do offer a very high sharpness and cutting ability though, and the lock mechanism can't be easily failed - you will just break the blade off. I also have the Ultra-Heavy duty model (0.7 mm thick), it is stiff and strong enough for any cuttig, even very heavy rope and thick wood. No batoning though I would assume. More to come as I work with them.
Link :
http://www.olfa.com/
-Cliff
