03-03-2021, 11:53 PM
Welcome to the Exchange!
FWIW, here’s what I do. Not saying it’s the best way, but it works for me.
99% of the time I use 3 belts; Cuitron 150, VF Scotch-Brite and the rough side of a leather belt with no compound. I prefer not to use compound because, as you mention, it removes tooth. You mention slower SFPM so it sounds like you have a variable speed grinder. I use a Kalamazoo 1SM (Kally), non-variable 1800 SFPM, https://kalamazooind.com/products/belt-s...lt-sander/ and a Kallyrest angle guide; https://www.mechusa.com
The biggest trick that requires the most practice is using the Scotch-Brite belt. It requires an extremely light touch to remove burr but not damage the edge. I’ve learned through a lot of experimentation to see what works. Now… This seems bizarre, but sometimes I’ll just barely tickle the edge against the Scotch-Brite at 45 degrees, just barely touching the edge just enough to chew up the burr a bit. Gotta be careful doing that and practice to see how far you can go, but it can be done.
I’ll also press the blade at 45 degrees to the leather belt. It’s surprising how much of that the edge can take, but then the edge is steel and the belt cow. Steel is much harder than cow.
The idea of the 45 degree thing is to bend the burr as much as possible in hope of stress fracturing it from the edge due to metal fatigue. Some burrs can bend back and forth forever as if they were made of gold, while others fracture quite quickly,
The last step is leather at sharpening angle to straighten up the edge. Without compound I’ve found that the edge can take pretty good belt/blade pressure and not remove tooth.
Admittedly, that process is a bit of an art form and requires practice. It also varies from edge to edge and how pesky the burr is to remove. Sometimes it’s easy, other times it can be a bit frustrating. Polishing an edge with compound to remove burr is generally quick and easy. For me at least a nice toothy edge is worth the extra effort of not using compound.
You mention your belt progression: 120 grit, A30 (800 grit). I’ve found 120 grit is more gnarly than necessary for general sharpening. It makes a toothy edge alright, but that coarse a belt is not necessary for a toothy edge. 150 grit is perfectly adequate. Additionally, 150 grit produces an edge that is toothy enough to stand up to a lot of leather belt work and pressure and still maintain tooth,
If the edge was super dull 120 grit would remove metal quickly but if hogging off lots of steel quickly is not the goal that coarse does not seem necessary. 150 grit removes plenty of steel and does not require much pressure to do it.
If you then do much grinding at all with the Trizact A30, the result will be an 800 grit edge, so unless a lot of lot of metal needs to be removed, what’s the point of the 120 belt? To me, an 800 grit edge is not toothy at all. If you start with an 800 grit edge and then use compound, it’s no wonder why the end result is a polished, not toothy edge.
Maybe try a 150 grit and skip the A30. Then try several of methods of deburring with/without compound and see how that works for you. The point is that 150 grit produces enough tooth to stand up to deburring on leather and still have “teeth” remaining after the deburring process. With an A30 grind, there is almost no tooth to start with and any additional work, especially with compound, will produce a polished edge.
Anyway, that’s what comes to mind. Hopefully it’s helpful. The key is to think about what you are doing and why. Then experiment to find a method that works best for you.
FWIW, here’s what I do. Not saying it’s the best way, but it works for me.
99% of the time I use 3 belts; Cuitron 150, VF Scotch-Brite and the rough side of a leather belt with no compound. I prefer not to use compound because, as you mention, it removes tooth. You mention slower SFPM so it sounds like you have a variable speed grinder. I use a Kalamazoo 1SM (Kally), non-variable 1800 SFPM, https://kalamazooind.com/products/belt-s...lt-sander/ and a Kallyrest angle guide; https://www.mechusa.com
The biggest trick that requires the most practice is using the Scotch-Brite belt. It requires an extremely light touch to remove burr but not damage the edge. I’ve learned through a lot of experimentation to see what works. Now… This seems bizarre, but sometimes I’ll just barely tickle the edge against the Scotch-Brite at 45 degrees, just barely touching the edge just enough to chew up the burr a bit. Gotta be careful doing that and practice to see how far you can go, but it can be done.
I’ll also press the blade at 45 degrees to the leather belt. It’s surprising how much of that the edge can take, but then the edge is steel and the belt cow. Steel is much harder than cow.
The idea of the 45 degree thing is to bend the burr as much as possible in hope of stress fracturing it from the edge due to metal fatigue. Some burrs can bend back and forth forever as if they were made of gold, while others fracture quite quickly,
The last step is leather at sharpening angle to straighten up the edge. Without compound I’ve found that the edge can take pretty good belt/blade pressure and not remove tooth.
Admittedly, that process is a bit of an art form and requires practice. It also varies from edge to edge and how pesky the burr is to remove. Sometimes it’s easy, other times it can be a bit frustrating. Polishing an edge with compound to remove burr is generally quick and easy. For me at least a nice toothy edge is worth the extra effort of not using compound.
You mention your belt progression: 120 grit, A30 (800 grit). I’ve found 120 grit is more gnarly than necessary for general sharpening. It makes a toothy edge alright, but that coarse a belt is not necessary for a toothy edge. 150 grit is perfectly adequate. Additionally, 150 grit produces an edge that is toothy enough to stand up to a lot of leather belt work and pressure and still maintain tooth,
If the edge was super dull 120 grit would remove metal quickly but if hogging off lots of steel quickly is not the goal that coarse does not seem necessary. 150 grit removes plenty of steel and does not require much pressure to do it.
If you then do much grinding at all with the Trizact A30, the result will be an 800 grit edge, so unless a lot of lot of metal needs to be removed, what’s the point of the 120 belt? To me, an 800 grit edge is not toothy at all. If you start with an 800 grit edge and then use compound, it’s no wonder why the end result is a polished, not toothy edge.
Maybe try a 150 grit and skip the A30. Then try several of methods of deburring with/without compound and see how that works for you. The point is that 150 grit produces enough tooth to stand up to deburring on leather and still have “teeth” remaining after the deburring process. With an A30 grind, there is almost no tooth to start with and any additional work, especially with compound, will produce a polished edge.
Anyway, that’s what comes to mind. Hopefully it’s helpful. The key is to think about what you are doing and why. Then experiment to find a method that works best for you.