03-04-2021, 08:48 PM
Okay… Here are some IMHO thoughts.
I have a few restaurant clients who complain that the knives aren't sharp when I use leather with compound, hence my trying to seek a toothier edge. One commercial account in particular is requesting an 800 grit finish, but with enough bite to grab a tomato skin, so that's why I've been using the A30 Trizact. Even when I can preserve the grind pattern, any use of compound is buffing off the teeth from the very apex.
Edge finish has little to do with sharpness as far as cutlery goes. Razor blades yes, cutlery no. Both a highly polished edge and a toothy edge can be very sharp. More than sharp enough to easly melt through tomato skin. A 150 polished edge and a 150 toothy will slice tomatoes easily. The problem I have found through experimentation is that when a polished edge dulls even slightly the smooth rolled edge rides on tomato skin, while the toothy edge keeps cutting.
It seems strange that your customers are complaining about an 800 grit edge. What sharpness readings do you get with the 800 grit edge? It seems that the edges you are producing must not be very sharp. When an edge is not sharp, my first thought is always remaining burr. But… Burr is rough with a very uneven surface. Burr generally cuts tomato skin quite well because it breaks the skin. It won’t last long because burr is crap metal, but right off the grinder I would think that it would.
So I am left puzzled. Again, what sharpness readings do you get with the 800 grit edge?
Even when I can preserve the grind pattern, any use of compound is buffing off the teeth from the very apex.
The grind pattern you see on the bevel may or may not be indicative of what is happening at the edge. You need a microscope to see if the grind pattern follows through to the edge. The apex is very thin and even if you can see scratching on the bevel the edge may still be polished with little “toothiness”. Additionally, to me at least, 800 grit produces a polished edge, not toothy. Compound applied to an 800 grit edge will no doubt produce an edge far more polished than toothy.
What kind of BESS reading are you getting with a 150 grit edge?
Generally greater than 80 and less than 150. Anything in that range works for cutlery. Not overly sharp so it dulls quickly, but sharp enough to work very well.
Curiously, the coarser the edge, the better it worked.
Yup. That is my finding as well. Toothy edges grab surfaces, break fibers and cut. Polished edges, unless extremely sharp, tend to ride on surfaces. Polished edges are good for push cutting, toothy edges like a miniature version of a serrated, edge work much better for slicing. When polished edges roll the roll is a long smooth surface, When toothy edges roll the roll is still a rough surface so it tends to keep cutting better when slicing.
do think that perhaps with water stones…
The sharpening method does not matter other than powered, and higher speed systems make it all happen much faster and with greater effect. In other words, the same results can be achieved with both powered and hand systems. By hand is just a LOT slower.
As you mention, Scotch-Brite (SB) is an abrasive and will produce burr. That seems paradoxical. The purpose of using SB is to grab and break the burr and base of the burr so that it can be removed with leather. SB must be used judicially or it defeats its purpose.
A toothy edge is created when a coarse abrasive cuts the apex leaving an uneven cut or “teeth”. The idea of using 150 grit is that it produces an edge that is toothy enough to withstand deburring and not get smooth during the process. How I do it, 150 grit seems to work well for that. If you use other deburring methods, like compound or grinding the burr with a finer abrasive then maybe a coarser abrasive like 120 grit might work better for your method. It’s a matter of creating an edge that it toothy enough so that when the burr is removed there is still remaining tooth.
Maybe you will find this interesting:
http://bessex.com/forum/showthread.php?t...he+lasting
I have a few restaurant clients who complain that the knives aren't sharp when I use leather with compound, hence my trying to seek a toothier edge. One commercial account in particular is requesting an 800 grit finish, but with enough bite to grab a tomato skin, so that's why I've been using the A30 Trizact. Even when I can preserve the grind pattern, any use of compound is buffing off the teeth from the very apex.
Edge finish has little to do with sharpness as far as cutlery goes. Razor blades yes, cutlery no. Both a highly polished edge and a toothy edge can be very sharp. More than sharp enough to easly melt through tomato skin. A 150 polished edge and a 150 toothy will slice tomatoes easily. The problem I have found through experimentation is that when a polished edge dulls even slightly the smooth rolled edge rides on tomato skin, while the toothy edge keeps cutting.
It seems strange that your customers are complaining about an 800 grit edge. What sharpness readings do you get with the 800 grit edge? It seems that the edges you are producing must not be very sharp. When an edge is not sharp, my first thought is always remaining burr. But… Burr is rough with a very uneven surface. Burr generally cuts tomato skin quite well because it breaks the skin. It won’t last long because burr is crap metal, but right off the grinder I would think that it would.
So I am left puzzled. Again, what sharpness readings do you get with the 800 grit edge?
Even when I can preserve the grind pattern, any use of compound is buffing off the teeth from the very apex.
The grind pattern you see on the bevel may or may not be indicative of what is happening at the edge. You need a microscope to see if the grind pattern follows through to the edge. The apex is very thin and even if you can see scratching on the bevel the edge may still be polished with little “toothiness”. Additionally, to me at least, 800 grit produces a polished edge, not toothy. Compound applied to an 800 grit edge will no doubt produce an edge far more polished than toothy.
What kind of BESS reading are you getting with a 150 grit edge?
Generally greater than 80 and less than 150. Anything in that range works for cutlery. Not overly sharp so it dulls quickly, but sharp enough to work very well.
Curiously, the coarser the edge, the better it worked.
Yup. That is my finding as well. Toothy edges grab surfaces, break fibers and cut. Polished edges, unless extremely sharp, tend to ride on surfaces. Polished edges are good for push cutting, toothy edges like a miniature version of a serrated, edge work much better for slicing. When polished edges roll the roll is a long smooth surface, When toothy edges roll the roll is still a rough surface so it tends to keep cutting better when slicing.
do think that perhaps with water stones…
The sharpening method does not matter other than powered, and higher speed systems make it all happen much faster and with greater effect. In other words, the same results can be achieved with both powered and hand systems. By hand is just a LOT slower.
As you mention, Scotch-Brite (SB) is an abrasive and will produce burr. That seems paradoxical. The purpose of using SB is to grab and break the burr and base of the burr so that it can be removed with leather. SB must be used judicially or it defeats its purpose.
A toothy edge is created when a coarse abrasive cuts the apex leaving an uneven cut or “teeth”. The idea of using 150 grit is that it produces an edge that is toothy enough to withstand deburring and not get smooth during the process. How I do it, 150 grit seems to work well for that. If you use other deburring methods, like compound or grinding the burr with a finer abrasive then maybe a coarser abrasive like 120 grit might work better for your method. It’s a matter of creating an edge that it toothy enough so that when the burr is removed there is still remaining tooth.
Maybe you will find this interesting:
http://bessex.com/forum/showthread.php?t...he+lasting