Cliff Stamp
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- Oct 5, 1998
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First off it would be worthwhile to make some comments about steeling as it would be useful to know why you would steel in general, before getting into the abilities of this particular piece of equipment.
When a knife blunts, the loss in cutting ability is often attributed to metal wear and thus a fresh honing is needed. However frequently the blunting is mainly due to deformation of the edge. This is a combination of impaction as well as the metal bending or rolling to the side. To restore the sharpness you can of course just use a hone to grind a fresh edge, repeating the initial sharpening process. However you can also just straighten the edge instead of grinding off all the deformed metal. This is steeling - alignment of the edge, straightening out all the bent parts and restoring it to s crisp and even line. For some additional reference material, Mike Swaim brought this topic up on rec.knives earlier this year under the topic heading "Is the butcher's "steel" obsolete?". It is a thread worth reading.
Since you hone to create the edge in the first place, why not just repeat this when the knife gets dull as noted? First off, the honing process is in general much longer than a simple steeling. To restore an edge with a steel, you don't need to stop cutting for more than a few seconds, and it doesn't deposit significant grit on the blade or on the hone so there is no cleanup after steeling. It also takes a lot less skill than freehand honing. In addition, steeling doesn't remove as much material as honing so it increases the "life" of a blade. Steels are also usually cheaper, more durable and are easier to maintain than hones. However with recent ceramic and diamond honing rod abrasives, a lot of these reasons are simply not true anymore.
For example a fine ceramic or diamond rod offers the same speed and simplicity of honing as a steel, and has none of the usual drawbacks of sharpening stones such as needing to be lapped or having to use oil/water. There is more metal removed with the ceramic and diamond rods, but you are looking at between 100 to 1000 sharpenings to remove one mm of metal from the edge of the knife depending on the edge angle and the grit of the ceramic or diamond hone - this is years of constant use. In general, the lifetime of most knives tends to be dominated by the occasional accidental damages that force heavy honing.
Is there any advantage to such rod honing rather than just using a smooth steel [a grooved steel is essentially a file when used heavily, but can act as a smooth steel when used lightly]. Yes. When you straighten the edge with a steel, even though it can get very sharp, within a few percent of optimal is possible, it is much less durable than when it was freshly honed and thus it will blunt faster. As well, if you don't use the steeled edge right away, it will actually relax back into a blunted condition. The same goes for the blunting as well, you can see an improvement in performance by just letting the blade sit unused after an extended session of heavy cutting.
This brings us to the Mouse Trap steel by Razor Edge Systems. Why use it rather than a simple smooth steel? First off all, using a freehand steel does requires some freehand skill. You have to use the right amount of force, and hold the blade at a consistent and correct angle. The tolerances for these actions are much greater than when you are honing on a benchstone, but still you can't be too sloppy and expect results. In comparison, in the Mouse Trap steel the force is controlled by counter weights so you can't press too heavy or too light, and drawing the blade through the rods (at preset angles) is a much simpler motion than using a regular steel so there is no angle requirement. As well, the Mouse Trap offers the possibility of removing one of the main drawbacks of regular
steels.
When using a regular steel, you will find that often the edge can be bent to one side when you finish, the opposite of whatever side you last stroked on the steel. Since the edge isn't straight out, you could in theory expect some performance loss over a perfectly perpendicular aligned edge. With the Mouse Trap, both sides are honed at the same time and thus there should be no side bias. This should make it be sharper and it seems logical it would last longer. However I have found in the past that regardless of the fact that steeled edges are very lightly bent to one side, they are still within a few percent of the cutting ability as the freshly honed edges, so I didn't expect much improvement in this area with the Mouse Trap. Mainly I was curious to see if there would be a difference in the edge retention of the steeled edges . However some use put a damper on my curiosity as I found with the the Mouse Trap that most edges would still end up biased to one side. In order to prevent this you have to compensate by drawing the blade through at a slight angle. The only knives that it would tend to produce perpendicular edges on consistently were very soft ones with acute edge angles such as found on Olfa blades.
To test the ability of the Mouse Trap vs a regular smooth steel, I used both to restore the same type of blade that had been blunted on 3/8" hemp rope (Olfa snapoff blades, 0.5 mm thick). After the blades were steeled the sharpness was measured (thread and 1/4 poly) to determine the effect of steeling. The blades then cut more rope until they blunted again to compare the edge retention of the two different steeled edges. The steeling was repeated three times in succession to look at extended use effects. 126 cuts were made each round, so four rounds total for each blade (one with freshly honed edge, three with steeled). Three blades were tested for each steel so in total, 24 rounds of 126 cuts. The regular steel I used was the folding steel from Razor Edge systems, the Raz-R steel. In short I found no significant difference in the initial sharpness of either type of steeled edge, nor in the edge retention. Lots of numbers there, send an email if you are interested in some numerical details. I also just used both on my regular utility knives and kitchen knives on a daily basis over a number of weeks to see if I would prefer the Mousetrap. No advantage was seen.
The Mousetrap also has a second feature which is that you can jam the blade all the way down and steel it very heavily using high force. You do this because the blade has now worn to such an extent that even when the edge is aligned the knife is still dull. Thus you need a way to do more than straighten the edge, it needs to be honed. The Mousetrap allows this by using a heavy load to smearing the metal out into a new edge, basically cold working the steel. While this is effective to a degree, the edge produced is relatively fragile. A butchers steel is better on softer kitchen knives at high force as it can file them and produces a much longer lasting slicing edge. A ceramic or diamond rod will also do a much better job in restoring such heavily blunted edges.
I also loaned it out to some friends. Basically two distinct groups of people who mainly used them on kitchen knives. The first group didn't tend to sharpen knives at all. They would have them sharpened occasionally and then let them dull to the extent that you had to tear or squash food. These people loved the Mouse Trap. Since the instructions are simple and there is no setup, anyone can start to use it in seconds. Using it as compared to doing nothing of course makes a tremendous difference and kitchen knives will stay pretty much at 100% sharpness for months with frequent steeling unless you heavily damage the edges. The second group used a regular smooth steel frequently. Those people tended to not be impressed. None of them preferred the Mouse Trap to a simple steel. It also a few drawbacks compared to a simple steel in that it can't handle knives that are ~3/16" or thicker, and is useless on knives with edges that are more obtuse than its preset angle.
Ref :
http://www.razoredgesystems.com/industrial/mt16.html
If you are curious how steeling can restore the cutting ability of a blade to within a few percent of optimal (by this I mean 95%+), so was I. Yes, some blunting is by deformation, but isn't some of it by wear - yes, a fair amount actually if you check the edge under magnification this is obvious. If this is the case then how can just steeling almost restore the edge to perfect condition? Well, steeling cheats a little. No, you can't restore the finish of the edge, there are all kids of irregularities where steel has been removed. However what steeling does to compensate for this is actually reducing the edge angle overall and raising the polish in places , by "smearing" out the steel in the edge. Thus since the cutting ability is a function of geometry and quality of finish, you can get the same level of cutting ability with a steeled edge that is worn, as a freshly honed edge, because the freshly honed edge is just a bit more obtuse, on a microscopic level and a bit more coarse. You can check this by noting that you can make a knife sharper after you finish honing by using a smooth steel. It tends to lower the edge durability though.
Thanks to Steve Bottorff, for providing this piece of equipment :
http://www.sharpeningmadeeasy.com/
and Razor's Edge for sending it to Steve :
http://www.razoredgesystems.com/
[90% of this was written before I made the recent thread on steeling <a href="http://www.bladeforums.com/forums/showthread.php?s=&threadid=217314">ref</a>, so there is some overlap between the two ]
When a knife blunts, the loss in cutting ability is often attributed to metal wear and thus a fresh honing is needed. However frequently the blunting is mainly due to deformation of the edge. This is a combination of impaction as well as the metal bending or rolling to the side. To restore the sharpness you can of course just use a hone to grind a fresh edge, repeating the initial sharpening process. However you can also just straighten the edge instead of grinding off all the deformed metal. This is steeling - alignment of the edge, straightening out all the bent parts and restoring it to s crisp and even line. For some additional reference material, Mike Swaim brought this topic up on rec.knives earlier this year under the topic heading "Is the butcher's "steel" obsolete?". It is a thread worth reading.
Since you hone to create the edge in the first place, why not just repeat this when the knife gets dull as noted? First off, the honing process is in general much longer than a simple steeling. To restore an edge with a steel, you don't need to stop cutting for more than a few seconds, and it doesn't deposit significant grit on the blade or on the hone so there is no cleanup after steeling. It also takes a lot less skill than freehand honing. In addition, steeling doesn't remove as much material as honing so it increases the "life" of a blade. Steels are also usually cheaper, more durable and are easier to maintain than hones. However with recent ceramic and diamond honing rod abrasives, a lot of these reasons are simply not true anymore.
For example a fine ceramic or diamond rod offers the same speed and simplicity of honing as a steel, and has none of the usual drawbacks of sharpening stones such as needing to be lapped or having to use oil/water. There is more metal removed with the ceramic and diamond rods, but you are looking at between 100 to 1000 sharpenings to remove one mm of metal from the edge of the knife depending on the edge angle and the grit of the ceramic or diamond hone - this is years of constant use. In general, the lifetime of most knives tends to be dominated by the occasional accidental damages that force heavy honing.
Is there any advantage to such rod honing rather than just using a smooth steel [a grooved steel is essentially a file when used heavily, but can act as a smooth steel when used lightly]. Yes. When you straighten the edge with a steel, even though it can get very sharp, within a few percent of optimal is possible, it is much less durable than when it was freshly honed and thus it will blunt faster. As well, if you don't use the steeled edge right away, it will actually relax back into a blunted condition. The same goes for the blunting as well, you can see an improvement in performance by just letting the blade sit unused after an extended session of heavy cutting.
This brings us to the Mouse Trap steel by Razor Edge Systems. Why use it rather than a simple smooth steel? First off all, using a freehand steel does requires some freehand skill. You have to use the right amount of force, and hold the blade at a consistent and correct angle. The tolerances for these actions are much greater than when you are honing on a benchstone, but still you can't be too sloppy and expect results. In comparison, in the Mouse Trap steel the force is controlled by counter weights so you can't press too heavy or too light, and drawing the blade through the rods (at preset angles) is a much simpler motion than using a regular steel so there is no angle requirement. As well, the Mouse Trap offers the possibility of removing one of the main drawbacks of regular
steels.
When using a regular steel, you will find that often the edge can be bent to one side when you finish, the opposite of whatever side you last stroked on the steel. Since the edge isn't straight out, you could in theory expect some performance loss over a perfectly perpendicular aligned edge. With the Mouse Trap, both sides are honed at the same time and thus there should be no side bias. This should make it be sharper and it seems logical it would last longer. However I have found in the past that regardless of the fact that steeled edges are very lightly bent to one side, they are still within a few percent of the cutting ability as the freshly honed edges, so I didn't expect much improvement in this area with the Mouse Trap. Mainly I was curious to see if there would be a difference in the edge retention of the steeled edges . However some use put a damper on my curiosity as I found with the the Mouse Trap that most edges would still end up biased to one side. In order to prevent this you have to compensate by drawing the blade through at a slight angle. The only knives that it would tend to produce perpendicular edges on consistently were very soft ones with acute edge angles such as found on Olfa blades.
To test the ability of the Mouse Trap vs a regular smooth steel, I used both to restore the same type of blade that had been blunted on 3/8" hemp rope (Olfa snapoff blades, 0.5 mm thick). After the blades were steeled the sharpness was measured (thread and 1/4 poly) to determine the effect of steeling. The blades then cut more rope until they blunted again to compare the edge retention of the two different steeled edges. The steeling was repeated three times in succession to look at extended use effects. 126 cuts were made each round, so four rounds total for each blade (one with freshly honed edge, three with steeled). Three blades were tested for each steel so in total, 24 rounds of 126 cuts. The regular steel I used was the folding steel from Razor Edge systems, the Raz-R steel. In short I found no significant difference in the initial sharpness of either type of steeled edge, nor in the edge retention. Lots of numbers there, send an email if you are interested in some numerical details. I also just used both on my regular utility knives and kitchen knives on a daily basis over a number of weeks to see if I would prefer the Mousetrap. No advantage was seen.
The Mousetrap also has a second feature which is that you can jam the blade all the way down and steel it very heavily using high force. You do this because the blade has now worn to such an extent that even when the edge is aligned the knife is still dull. Thus you need a way to do more than straighten the edge, it needs to be honed. The Mousetrap allows this by using a heavy load to smearing the metal out into a new edge, basically cold working the steel. While this is effective to a degree, the edge produced is relatively fragile. A butchers steel is better on softer kitchen knives at high force as it can file them and produces a much longer lasting slicing edge. A ceramic or diamond rod will also do a much better job in restoring such heavily blunted edges.
I also loaned it out to some friends. Basically two distinct groups of people who mainly used them on kitchen knives. The first group didn't tend to sharpen knives at all. They would have them sharpened occasionally and then let them dull to the extent that you had to tear or squash food. These people loved the Mouse Trap. Since the instructions are simple and there is no setup, anyone can start to use it in seconds. Using it as compared to doing nothing of course makes a tremendous difference and kitchen knives will stay pretty much at 100% sharpness for months with frequent steeling unless you heavily damage the edges. The second group used a regular smooth steel frequently. Those people tended to not be impressed. None of them preferred the Mouse Trap to a simple steel. It also a few drawbacks compared to a simple steel in that it can't handle knives that are ~3/16" or thicker, and is useless on knives with edges that are more obtuse than its preset angle.
Ref :
http://www.razoredgesystems.com/industrial/mt16.html
If you are curious how steeling can restore the cutting ability of a blade to within a few percent of optimal (by this I mean 95%+), so was I. Yes, some blunting is by deformation, but isn't some of it by wear - yes, a fair amount actually if you check the edge under magnification this is obvious. If this is the case then how can just steeling almost restore the edge to perfect condition? Well, steeling cheats a little. No, you can't restore the finish of the edge, there are all kids of irregularities where steel has been removed. However what steeling does to compensate for this is actually reducing the edge angle overall and raising the polish in places , by "smearing" out the steel in the edge. Thus since the cutting ability is a function of geometry and quality of finish, you can get the same level of cutting ability with a steeled edge that is worn, as a freshly honed edge, because the freshly honed edge is just a bit more obtuse, on a microscopic level and a bit more coarse. You can check this by noting that you can make a knife sharper after you finish honing by using a smooth steel. It tends to lower the edge durability though.
Thanks to Steve Bottorff, for providing this piece of equipment :
http://www.sharpeningmadeeasy.com/
and Razor's Edge for sending it to Steve :
http://www.razoredgesystems.com/
[90% of this was written before I made the recent thread on steeling <a href="http://www.bladeforums.com/forums/showthread.php?s=&threadid=217314">ref</a>, so there is some overlap between the two ]
