Scratch direction on bevels

[Miyamoto Musashi]

Hi,

When either thinning/finishing bevels with stones, when is it advisable to change the direction of the scratches? Under what circumstances is this both necessary and not necessary? What is your technique for going about it?

Thank you!

 

[Choppin]

I change directions when polishing, every time I move to a finer stone. Seems more effective to remove the previous grit's scratches. I usually alternate between 45 degrees (knife to stone) and parallel.

Same goes for sandpaper finishing.

 

[user 16756]

I only do it on coarser stones, which for me means synthetics, to see where I'm hitting.

In general while polishing with finishers I just stick to parallel to the edge.

I suspect @milangravier probably has some opinions on the matter.

 

[Heckel7302]

I thought about asking this question also. Typically I'm with @tcmx3, alternate in the synth prep stages, stick to parallel after moving to naturals. It seems to give me a more even finish that way, especially under my novice hands.

@ethompson?

 

[ethompson]

If I’m going for a very clean nice polish, I change directions between every synth and usually also polish two ways on my last synthetic or first natural (maybe overkill, but guarantees a clean base). From there I’m less worried about scratch direction than whatever technique allows me to best apply consistent strokes the the blade at hand. It is often parallel to the edge.

If it’s not something I’m super worried about, then I’ll stick to mostly one direction to help blend things in.

 

[TB_London]

Yeah changing direction helps confirm all previous scratches have gone. I’ll do it if going for a really fine polish. Otherwise keep everything in the same direction and embrace the satin finish.

 

[milangravier]

Changing scratch direction when shaping/thinning you bevels is most important.
First like any polishing work (meaning with any tools you would use), crossing the scratch directions will allow you to properly see if you have erased all the previous scratches.
Second : scratch direction have an effect on the way you grind your bevel. What I mean is that each scratch direction will hit the surface in a certain way, touching more or less surface and allow you to give a certain shape to your bevel. That second point is often not considered but it is true tool for the people who understand it.
-Longitudinal scratches (parallel to the edge) is generally the scratch direction that will hit the most of the surface, that will give a less efficient work as the stone got to grind more material at every raw. That direction will be great to align your bevel and give a longitudinal slightly convex surface. Other issue is that it is easy to roll on shinogi with that direction as you don't work against it but parallel to it.
-Diagonal looks to be great for flattening the surface. Less surface to work so little more efficient. Good for blending different facets. Preserve shinogi. Overall the most used scratch direction to finish a knife because it is very polyvalent. I would say it is not the most pretty finish and I like to get scratch pattern more parallel to the edge for final polish.
-Perpendicular is the best direction to grind. Less surface to work with so more efficient. You can also roll on shinogi if you hit too hard. You can create a bad shape and low spots longitudinally because you're working on one spot with power and can easily overgrind (most often at the heel area). That direction is also great to create and control some convexity : you're perpendicular to the edge so you can really shape your convexity from shinogi to edge the way you want.
I use all 3 when I am shaping the bevel, depending what shape I want to create. I will work diagonal and longitudinal close to shinogi. I will work perpendicular and longitudinal close to the edge.
I cross scratch direction at every grit of my progression. When I reach natural stones I will only work in one direction (longitudinal mostly), except if I want to check some scratch I have trouble to erase or if I want perfect cleanness.

 

[KnightKnightForever]

Changing scratch direction when shaping/thinning you bevels is most important.
First like any polishing work (meaning with any tools you would use), crossing the scratch directions will allow you to properly see if you have erased all the previous scratches.
Second : scratch direction have an effect on the way you grind your bevel. What I mean is that each scratch direction will hit the surface in a certain way, touching more or less surface and allow you to give a certain shape to your bevel. That second point is often not considered but it is true tool for the people who understand it.
-Longitudinal scratches (parallel to the edge) is generally the scratch direction that will hit the most of the surface, that will give a less efficient work as the stone got to grind more material at every raw. That direction will be great to align your bevel and give a longitudinal slightly convex surface. Other issue is that it is easy to roll on shinogi with that direction as you don't work against it but parallel to it.
-Diagonal looks to be great for flattening the surface. Less surface to work so little more efficient. Good for blending different facets. Preserve shinogi. Overall the most used scratch direction to finish a knife because it is very polyvalent. I would say it is not the most pretty finish and I like to get scratch pattern more parallel to the edge for final polish.
-Perpendicular is the best direction to grind. Less surface to work with so more efficient. You can also roll on shinogi if you hit too hard. You can create a bad shape and low spots longitudinally because you're working on one spot with power and can easily overgrind (most often at the heel area). That direction is also great to create and control some convexity : you're perpendicular to the edge so you can really shape your convexity from shinogi to edge the way you want.
I use all 3 when I am shaping the bevel, depending what shape I want to create. I will work diagonal and longitudinal close to shinogi. I will work perpendicular and longitudinal close to the edge.
I cross scratch direction at every grit of my progression. When I reach natural stones I will only work in one direction (longitudinal mostly), except if I want to check some scratch I have trouble to erase or if I want perfect cleanness.

Have any videos?

 

[milangravier]

Have any videos?

On my instagram there is quite a lot of video about stone polishing

 

[KnightKnightForever]

On my instagram there is quite a lot of video about stone polishing

Yes I've seen several. I guess for some reason I was under the impression you had to sharpen the same direction all the way through the grits. Noob

 

[Miyamoto Musashi]

Changing scratch direction when shaping/thinning you bevels is most important.
First like any polishing work (meaning with any tools you would use), crossing the scratch directions will allow you to properly see if you have erased all the previous scratches.
Second : scratch direction have an effect on the way you grind your bevel. What I mean is that each scratch direction will hit the surface in a certain way, touching more or less surface and allow you to give a certain shape to your bevel. That second point is often not considered but it is true tool for the people who understand it.
-Longitudinal scratches (parallel to the edge) is generally the scratch direction that will hit the most of the surface, that will give a less efficient work as the stone got to grind more material at every raw. That direction will be great to align your bevel and give a longitudinal slightly convex surface. Other issue is that it is easy to roll on shinogi with that direction as you don't work against it but parallel to it.
-Diagonal looks to be great for flattening the surface. Less surface to work so little more efficient. Good for blending different facets. Preserve shinogi. Overall the most used scratch direction to finish a knife because it is very polyvalent. I would say it is not the most pretty finish and I like to get scratch pattern more parallel to the edge for final polish.
-Perpendicular is the best direction to grind. Less surface to work with so more efficient. You can also roll on shinogi if you hit too hard. You can create a bad shape and low spots longitudinally because you're working on one spot with power and can easily overgrind (most often at the heel area). That direction is also great to create and control some convexity : you're perpendicular to the edge so you can really shape your convexity from shinogi to edge the way you want.
I use all 3 when I am shaping the bevel, depending what shape I want to create. I will work diagonal and longitudinal close to shinogi. I will work perpendicular and longitudinal close to the edge.
I cross scratch direction at every grit of my progression. When I reach natural stones I will only work in one direction (longitudinal mostly), except if I want to check some scratch I have trouble to erase or if I want perfect cleanness.

Thank you for taking the time to write all of this. This was immensely helpful.