Removing file marks on bevel easily and quickly

T

Tehemton

Joined
Sep 6, 2016
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I've made a few knives so far and I file my bevels using a modified jig with a flap disc for the initial bulk removal and file for getting perfect bevels.
However after filing, the file marks are very tough to take out and require two hours just on the 80 grit paper, and the flap discs are too aggressive for this and can ruin the grind.. Is there something I'm missing or can the fiber discs/scotch Brite discs be used on the angle grinder to take the file marks out slightly quickly without being too aggressive.
Any advice is welcome.
Thanks
Regards
Tehemton
 
Vastly more knowledgeable people will show up shortly, but I'll tell you what I do is:
A) clean the file out very often with a file card
B) follow up with a coarse silicon carbide stone--it is extremely flat and rigid, and cuts quickly. I then start with 100 grit paper and go on up.
 
t1mpani said:
Vastly more knowledgeable people will show up shortly, but I'll tell you what I do is:
A) clean the file out very often with a file card
B) follow up with a coarse silicon carbide stone--it is extremely flat and rigid, and cuts quickly. I then start with 100 grit paper and go on up.
Click to expand...

Thanks for the tip. Do you oil it or use plain water? Also mount it on the jig or freehand it?
 
You can use power drill with this set up. Use rigid holder for discs, start with 120-150 grit disc then higher grits. Be careful discs are pretty aggressive at higher speed so use low rpm. If You don't have power drill You can use angle grinder with similar holder.
 
Tehemton said:
I've made a few knives so far and I file my bevels using a modified jig with a flap disc for the initial bulk removal and file for getting perfect bevels.
However after filing, the file marks are very tough to take out and require two hours just on the 80 grit paper, and the flap discs are too aggressive for this and can ruin the grind.. Is there something I'm missing or can the fiber discs/scotch Brite discs be used on the angle grinder to take the file marks out slightly quickly without being too aggressive.
Any advice is welcome.
Thanks
Regards
Tehemton
Click to expand...

You can try this way , it s work for me .

a3o9hh.jpg

152gv80.jpg
 
If you're set on using an angle grinder, use a finer disc after your flapper wheel. Look up unitized discs.
 
You should step up in file coarseness the same way you would with sandpaper. Start with an aggressive file, remove all of the marks left by your angle grinding. Move to a finer cutting mill file, remove all the course file cuts, then use a fine finish cut file and do it again. Then when you start with 80 grit paper you'll bet much closer to where you want to be.

Additionally I'm guessing without pictures but I think sometimes what seems like just "file marks" when this issue comes up is actually surface deviations that someone has put into their blade by hitting an area harder than the rest of the bevel and wallowing it out. Essentially digging a ditch that is hard to see until you start sanding and the surrounding surface profile has enough contrast to show it. So be careful to establish flat, true bevels.

Last, keeping the file clean will reduce marking. A lot of "file marks" are actually chips being dragged and rolled over the files teeth getting between the file and the work. These will dig deeper than the file marks themselves because they are stacked on the teeth of the file and act like a peak that can dig into the work 2 or 3 times the depth of the actual file marks.
 
"When you're sanding out scratches, you're not sanding scratches. You're sanding everything that is NOT a scratch." Me.

In your words, ".......the file marks are very tough to take out." think about that.
You are not 'removing' a scratch. There's already NOTHING there! It's a VOID. It's an absence of material.
What you are having to do is bring EVERYTHING down to the level equal to the bottom of the void.

You just simply ended with too many deep scratches during your last step.
Switch to a finer tooth file to get everything nice and smooth.

Think about what's happening.
 
Thanks a lot guys!
I tried the silicon carbide stone and that took care of most of the scratches. You are correct, the scratches were because my file had some chips clogged up.. I've gotten rid of almost all the scratches and only a handful short ones remain where my flat grind starts.
I'm going to progress up in files and keep them clean like you suggested which should hopefully make the cleanup easier next knife onwards.
On a side note, does acid washing the blade hide some scratches or will they be apparent? I don't want to sand too much as it's smoothing out the bevel edge that meets the flat. I'm sorry I'm relatively new here and still trying maneuver around in terms of uploading pics.
Again, I appreciate all the help. Cheers
 
Tehemton said:
Thanks a lot guys!
I tried the silicon carbide stone and that took care of most of the scratches. You are correct, the scratches were because my file had some chips clogged up.. I've gotten rid of almost all the scratches and only a handful short ones remain where my flat grind starts.
I'm going to progress up in files and keep them clean like you suggested which should hopefully make the cleanup easier next knife onwards.
On a side note, does acid washing the blade hide some scratches or will they be apparent? I don't want to sand too much as it's smoothing out the bevel edge that meets the flat. I'm sorry I'm relatively new here and still trying maneuver around in terms of uploading pics.
Again, I appreciate all the help. Cheers
Click to expand...

Acid etching can hide some scratches, but only very very fine ones. I think it only hides them by making the material less reflective of light, it doesn't change the surface profile enough to change their depth, unless you etch to the point of pitting.
 
kuraki said:
Acid etching can hide some scratches, but only very very fine ones. I think it only hides them by making the material less reflective of light, it doesn't change the surface profile enough to change their depth, unless you etch to the point of pitting.
Click to expand...

Thought so.. Thank you so much for all the info
 
Karl B. Andersen said:
"When you're sanding out scratches, you're not sanding scratches. You're sanding everything that is NOT a scratch." Me.

In your words, ".......the file marks are very tough to take out." think about that.
You are not 'removing' a scratch. There's already NOTHING there! It's a VOID. It's an absence of material.
What you are having to do is bring EVERYTHING down to the level equal to the bottom of the void.

You just simply ended with too many deep scratches during your last step.
Switch to a finer tooth file to get everything nice and smooth.

Think about what's happening.
Click to expand...

I wish there was a like button for this comment! Excellent point!
 
And as AF said are you "draw filing" or just filing away? Draw filing is as it says. You draw the file towards you OFF of the material and make contact with the material when moving the file away from you. Your files will last longer and cut much cleaner.
Frank
 
Frank Niro said:
And as AF said are you "draw filing" or just filing away? Draw filing is as it says. You draw the file towards you OFF of the material and make contact with the material when moving the file away from you. Your files will last longer and cut much cleaner.
Frank
Click to expand...

I am filing properly though, just didn't think cleaning them up would make such a huge difference.
Also I was looking for a less labor intensive method to get the file marks off. Like Kevin said.. I'll try out some fine non woven abrasive discs to get the initial grit marks off before starting to hand sand everything to a nice satin finish.
 
Tehemton said:
Thanks for the tip. Do you oil it or use plain water? Also mount it on the jig or freehand it?
Click to expand...

Sorry, work got very busy and I forgot about my post--although as predicted, others came in and delivered wisdom. :)

Still, I'll go ahead and answer: I use oil (generally Break-Free as I have ridiculous amounts of it), and I free-hand using what I'd call "medium" pressure, pressing down a little bit but keeping perfect contact and not rocking around being my primary goal. Jigs are great in some cases but, just like a Smith machine vs. free weights, they lock you into one particular motion/angle which may not be the greatest choice depending on the desired shape of your bevels.
 
kuraki said:
Acid etching can hide some scratches, but only very very fine ones. I think it only hides them by making the material less reflective of light, it doesn't change the surface profile enough to change their depth, unless you etch to the point of pitting.
Click to expand...

Acid etching makes medium and big scratches look bigger.
 
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