scotch brite belt questions

[J.H.]

i just got a fine scotch brite belt to try getting a satin machine finish on my blades, but i seem to have some issues with using it. I am getting some weird scratches along the edge, and the same scratches (more like dots) on the opposite bevel which isnt even contacting the belt.

Does anyone recognize this problem, i tried on a couple of test blades using different pressure etc, but it seems to show up no matter what.
Could it be wrong angle? its a bit different finding the flat on a spongy belt.
Also as you will see in the image there are some angled scratches on the bevel, but i think that was just me being sloppy.

Im still very much a noob grinder with only a couple of test blades under my belt so dont discount any seemingly obvious problems.

The test blade is mild steel ground to an a45 gator belt finish before the fine scotch brite belt.

 

[3fifty7]

While being far from an expert, I attribute that to the steel quality rather than to the belt finish.

 

[J.H.]

ah yeah i could see that, i did consider it being due to not being hardened. will have to try next time grinding a real blade, and worst case the a45 gator finish will have to do, which did leave quite a nice finish to be honest.

 

[E.Carlson]

Did you wipe the blade clean with something after using the belt? Looks like loose grit scratches

 

[J.H.]

yeah, i just tried rubbing with some steel wool in case the scratches was some sort of residue from the new belt; but what you see in the red circle was definitely there before.

 

[Storm W]

If it isn't hard and you are leaning one it you might be removing material at the edge rather than smoothing the scratch pattern. To get a nice finish I have to start with a nice finish. I run mine wide open with light pressure for the one that turn out well. I feel like you match the grit to the scotch scotchbrite and it knocks the tops of of the scratch pattern and makes it look a bit softer.

 

[A.McPherson]

Are you grinding edge up or down?

If edge up, there could be a couple loose fibers of the belt, slinging over the top edge to hit on the opposite side.

Try rotating the belt by hand and really taking a good hard look at the belt to see if there are any loose fibers...

 

[butcher_block]

Are you grinding edge up or down?

If edge up, there could be a couple loose fibers of the belt, slinging over the top edge to hit on the opposite side.

Try rotating the belt by hand and really taking a good hard look at the belt to see if there are any loose fibers...

thats what it looks like to me wrap around fuzz making hazy finish i always finish flats after bevels cause of it

 

[Ken H>]

I suspect you might find a hardened blade will polish up better also. Next attempt try using a hardened blade and MAKE sure to grind with belt running away from edge, either with edge turned down, or even better run grinder in reverse so you can see the edge.

 

[MadmanR1]

I remember seeing the same on my test pieces.

I started spraying the belt with wd40, using high speed, less pressure, edge down, on hardened steel and I haven't seen since.

 

[J.H.]

Thanks everyone for the advice, it seems to have been a couple of loose fibers which i just trimmed off and it left a much nicer finish.

PS. trying to grind a folding knife while im still a noob was a real pain... nothing to hold on to when grinding lol

 

[Busto]

Thanks everyone for the advice, it seems to have been a couple of loose fibers which i just trimmed off and it left a much nicer finish.

PS. trying to grind a folding knife while im still a noob was a real pain... nothing to hold on to when grinding lol

Try using small needle nose vise grips with a piece of leather folded over so the jaws don't scratch the tang to hold your work piece.

 

[J.H.]

thanks i may give that a try if i decide to make another friction folder. I did try using a file guide which gives you something to hold on to, but that only reduced the feedback i got into my hand which made it harder.

 

[john april]

i bet if you carefully painted some nail polish above the bevel, that would be just enough to protect the flats from the little pieces that go over the edge. or if its straight along the top, a piece of tape.