burrs, scratch patterns, and grit time.

williamsld8

williamsld8

Joined
Sep 19, 2010
Messages
226
So I have always been able to achieve a burr if desired, and can usually get my edges as close to mirror finish as possible, but with still a tiny haze. I have looked at knifenut's first sharpening thread and the mirror sheen on that edge makes mine look like trash. I'm thinking the reason I still have a haze is using too much pressure on the grit prior to stropping, as well as not spending enough time on it, meaning I have left over scratches from my second to last grit, and scratches from the last grit that are deeper than they should be due to undue pressure, which results in my mirror finish looking like a dirty mirror. Does this sound right? And I normally stop on one side at one grit as soon as I have achieved a full length burr. Is it (depending on the circumstances) sometimes necessary to stay on a grit after your burr forms to continue refining the scratch pattern?
 
What's the easiest method to actually observe a scratch pattern and determine whether or not you've gotten rid of the old one?
 
I would call it crosshatching. I do one grit in this direction ///////////// and the next \\\\\\\\\\\\\\\ when all the XXXXXXXXXXs disappear and all you see are \\\\\\\\ switch. I hope you understood that. I really suck at explaining things. :)
 
Look closely. You need the edge within 12in of your eyes to see full detail.

What tools are you using and in what order?

Steel type and maker?

A mirror polish truly starts at 14k or 1 micron, anything coarser will show scratches.

A scratch in a mirror surface sticks out like a sore thumb, a haze is typical of a abrasive that is not fine enough and if you have a mirror surface with "Orange peel" you didn't step down the grits in close enough order prior to polishing.



Forming a burr is a sign bevel slope "A" and "B" have intersected but it does not mean you are done. With each formation of a burr that will happen at EACH progression of grit you can also remove it with that grit if proper technique and pressure is used. Think of forming the burr as a transformation of grit and its removal as the completion of this transformation. As you grind with each stone you have a sudden build-up of the burr and as you decrease pressure and refine the bevel with that stone the burr decreases and the scratch pattern refined within that grit. Once all that happens you are ready for the next stone.
 
Last edited:
mongolguy said:
I would call it crosshatching. I do one grit in this direction ///////////// and the next \\\\\\\\\\\\\\\ when all the XXXXXXXXXXs disappear and all you see are \\\\\\\\ switch. I hope you understood that. I really suck at explaining things. :)
Click to expand...
You couldn't be more clear. Perfect example! Thank you for the tip!
 
knifenut1013 said:
Look closely. You need the edge within 12in of your eyes to see full detail.

What tools are you using and in what order?

Steel type and maker?

A mirror polish truly starts at 14k or 1 micron, anything coarser will show scratches.
Click to expand...

Various steels from various makers, because I am practicing this on most of my folders. And I have DMT Diafolds, XC, C, F, EF, then a strop with black compound which I picked up to help the transition between EF and green compound, and then strop with green compound.
 
That's still too much, you would still need DMT 6, 3, and 1 micron pasted before either of those compounds. It's also going to make a big difference from 1095-S30V in terms of cutting speed and effective polish the compound will produce.
 
whats the approx micron size of the EF, black compound, and green compound? just so i have a better idea of the gap in micron sizes im using.
 
EF is 9 microns and is a fixed and very sharp abrasive. Black compound is usually something like Boron carbide @ 1 micron and green compound is usually chromium oxide @ .5 microns. So the progression in "grit" would be like 1000-14,000-50,000

I would go with polishing stones before a bunch of compounds though. One good stone could do the work of several compounds.
 
That might work but what is your goal in sharpening?
 
well my current goal is to achieve a mirror finish without a haze, and also make one sharp enough to shave my face. I have achieved every sharpening goal so far except this one.
 
A good mirror finish is one of the harder goals of sharpening. Mixing stones, hones, and compounds is difficult and often confusing, and if you mix them the wrong way you never get the results desired. Your best bet would be the DMT compound on balsa wood or MDF, you could get the EEF but it would kinda be a waste because the diapaste was made before the EEF came along and will work with or without it.

If you want to skip the compounds and use stones then waterstones would be the way to go but that's a investment in a permanent sharpening set-up.
 
huuumm knifenut imho the average black compund like bark river's and the usual shop one is wayyyy coarser that 1 micron and is more likely Al Ox or SiC or a mix of both.

actually most cheap green sticks are close or over 1mic, you are talking about the high end one you use that's not true for the big waxy bars.
 
That's why I say "usually"

I don't and won't use wax bar compound because its "dirty" when compared to quality compounds made for honing.
 
You must log in or register to reply here.
Back
Top