Recommendation? Edge thickness before sanding

[wohmsc]

Hi all, currently working on a chef knife, I am post heat treat and my bevels are roughly ground in, I've just used uo all my 80 grit and my edge is at around 0.6mm. I want to work this down to around 0.3-0.4mm before sharpening.

Will working up the rest of the grits be able to get me in that general ballpark? (Aiming for around 600 grit before etch.)

I'm also wondering of during the etch the thickness may reduce a bit too?

Not sure how to proceed at the moment, any advice will be greatly appreciated.
Thanks.

 

[Jdottinger]

Hi all, currently working on a chef knife, I am post heat treat and my bevels are roughly ground in, I've just used uo all my 80 grit and my edge is at around 0.6mm. I want to work this down to around 0.3-0.4mm before sharpening.

Will working up the rest of the grits be able to get me in that general ballpark? (Aiming for around 600 grit before etch.)

I'm also wondering of during the etch the thickness may reduce a bit too?

Not sure how to proceed at the moment, any advice will be greatly appreciated.
Thanks.

You’d probably get a better answer in the shoptalk sub forum. You can ask a mod to relocate your thread by reporting your post. Good luck.

 

[wohmsc]

You’d probably get a better answer in the shoptalk sub forum. You can ask a mod to relocate your thread by reporting your post. Good luck.

Ok I'll do that thank you!

 

[Sando]

Hi all, currently working on a chef knife, I am post heat treat and my bevels are roughly ground in, I've just used uo all my 80 grit and my edge is at around 0.6mm. I want to work this down to around 0.3-0.4mm before sharpening.

Will working up the rest of the grits be able to get me in that general ballpark? (Aiming for around 600 grit before etch.)

I'm also wondering of during the etch the thickness may reduce a bit too?

Not sure how to proceed at the moment, any advice will be greatly appreciated.
Thanks.

Hi. You've come to the right place.

Here's how I do it, but everyone's got their own methods/opinions.

Etching won't effect enough to matter. However you'll want to knock the edge back just a tad to make sure you have clean steel. In other words, take the edge a little thinner than you want. Then drag the edge on a stone to bring it back to what you need. Usually just a few passes does it.

I like to take my common kitchen knives to 0.15 to 0.17 mm before sharpening. 0.25mm would be my personal max.

 

[HSC ///]

as already mentioned, .3-.4 mm is too thick

 

[DevinT]

It also depends on what kind grind you’re doing.

Sanding and etching will reduce the thickness, for kitchen knives, thin is better. Grind to size and finish from there.

Hoss

 

[HSC ///]

 

[Sando]

Hi all, currently working on a chef knife, I am post heat treat and my bevels are roughly ground in, I've just used uo all my 80 grit and my edge is at around 0.6mm. I want to work this down to around 0.3-0.4mm before sharpening.

Will working up the rest of the grits be able to get me in that general ballpark? (Aiming for around 600 grit before etch.)

I'm also wondering of during the etch the thickness may reduce a bit too?

Not sure how to proceed at the moment, any advice will be greatly appreciated.
Thanks.

I'm sorry we forgot one of your questions.

Will working up the rest of the grits be able to get me in that general ballpark?

I have a spreadsheet with a table of how deep the scratches from various grits are. It calculates edge thickness after each sanding pass.

I put in your parameters with 4 more passes starting from 80 grit: 120, 220, 600 and it came out to 0.03mm.

Of course that's only a SWAG, because your technique and what grits you use will vary.

 

[wohmsc]

I'm sorry we forgot one of your questions.


I have a spreadsheet with a table of how deep the scratches from various grits are. It calculates edge thickness after each sanding pass.

I put in your parameters with 4 more passes starting from 80 grit: 120, 220, 600 and it came out to 0.03mm.

Of course that's only a SWAG, because your technique and what grits you use will vary.

Ok thank you that's interesting, I went back to a 60 grit paper today and thinned the edge out a little more, and then I will work up the grits again, if I can get at most 0.3 mm thick then I'll be happy, and based off of what you have said that could be quite acheivable? I like to spend plenty of time on the sanding so I should hopefully work it down quite a bit.

 

[Alex Topfer]

I get it thin enough to cut the sandpaper then once i'm done i put on a secondary bevel to stabilise the edge. you can feel it if you get it too thin

 

[Justin W]

Ok thank you that's interesting, I went back to a 60 grit paper today and thinned the edge out a little more, and then I will work up the grits again, if I can get at most 0.3 mm thick then I'll be happy, and based off of what you have said that could be quite acheivable? I like to spend plenty of time on the sanding so I should hopefully work it down quite a bit.

If you have a flat reference stone or sink cutout that you can lay a sheet of sandpaper on, use it to change your scratch direction. Spritz a light spray of water on your surface, then lay the paper down, it helps make it stick in place. Then lay your blade bevel down flat and sand (I sand wet). If you hand sand length wise, this way puts scratches in bladewise, or 90 degrees shifted to your hand sanding motion. Most YouTube tutorials on this method call it thinning. In my experience, it is faster at thinning a bevel than hand sanding lengthwise, but it can leave the occasional deep scratch that is hard to clean up. I will alternate between lengthwise and bladewise until desired thinness (i.e. pretty darn close to 0). Usually by 220 or 320 grit I will hit 0 tbe and have to cut the burr off with some light slicing motions blade on sandpaper.

Hand sanding is usually when I cut myself on a blade that isn't sharpened, but still thin enough most people would call it "sharp." Just a few passes on sharpening stones later is when it is truly sharp. Nothing cuts better than a thin blade.

 

[wohmsc]

If you have a flat reference stone or sink cutout that you can lay a sheet of sandpaper on, use it to change your scratch direction. Spritz a light spray of water on your surface, then lay the paper down, it helps make it stick in place. Then lay your blade bevel down flat and sand (I sand wet). If you hand sand length wise, this way puts scratches in bladewise, or 90 degrees shifted to your hand sanding motion. Most YouTube tutorials on this method call it thinning. In my experience, it is faster at thinning a bevel than hand sanding lengthwise, but it can leave the occasional deep scratch that is hard to clean up. I will alternate between lengthwise and bladewise until desired thinness (i.e. pretty darn close to 0). Usually by 220 or 320 grit I will hit 0 tbe and have to cut the burr off with some light slicing motions blade on sandpaper.

Hand sanding is usually when I cut myself on a blade that isn't sharpened, but still thin enough most people would call it "sharp." Just a few passes on sharpening stones later is when it is truly sharp. Nothing cuts better than a thin blade.

Hi,
I've been doing a mix if hand sanding and the mehmthod you have just mentioned, I must say it does feel like it works faster I'm just concerned about those deep scratches you mentioned, I have found that even working with tye same grit they can be a challenge to get out.

 

[Stacy E. Apelt - Bladesmith]

When you discover deep scratches go back one grit size and sand until they are gone before going back up the grits. Finer sandpaper will not sand out coarser scratches very well.

 

[Justin W]

When you discover deep scratches go back one grit size and sand until they are gone before going back up the grits. Finer sandpaper will not sand out coarser scratches very well.

Yes, but W wohmsc and I are doing this in the same grit. I generally only do this at 120 grit just after I stop using the grinder. For me, the deep 120 grit new scratches are still ok since they are still finer than belt scratches. They show me precisely where I left too deep a scratch when grinding, and those need to be removed one way or another.

OP, sometimes I use paper that has already been used for thinning passes. It knocks down the extra high grits, and any loose grits will have also been scraped/rinsed away. But, doing it this way, the paper isn't very flat anymore, so not perfect.

 

[wohmsc]

Yes, but W wohmsc and I are doing this in the same grit. I generally only do this at 120 grit just after I stop using the grinder. For me, the deep 120 grit new scratches are still ok since they are still finer than belt scratches. They show me precisely where I left too deep a scratch when grinding, and those need to be removed one way or another.

OP, sometimes I use paper that has already been used for thinning passes. It knocks down the extra high grits, and any loose grits will have also been scraped/rinsed away. But, doing it this way, the paper isn't very flat anymore, so not perfect.

Ok thank you, I sent use a grinder unfortunately, all done by hand so I have to start from the lowest grit woth sandpaper after using the file grinding method, but I assume the same process remains the same throughout