Not your every day mirror edge

Use edge to cut into wood (against or with grain depend on bevel depth) or plastic. Load abrasive, light sawing to distribute & adhere abrasive to the sides of the cut. Start sawing with more pressure, you can nurse the apex by controlling the additional amount of the cut depth penetration. Choose whatever wood size/shape/hardness/etc.. work for you.

The far right notch was used for the last knife pic I posted
62in.jpg
 
Black(250 grit) & White(1200 grit) compounds from UsaKnifeMaker (under buffing section). The 2 most versatile & cheap (around $15 for 2 lbs) bulk abrasives I used all the time for most steels. I can get almost mirror just from the white compound. I am not sure when one would use up a 2 pounds bar of compound.

Diamond pastes 12um to 0.1um from AdvancedAbrasives to cover high alloy blades and refine to complete mirror.
 
the edge looks good but is it actually sharp after all that sawing or just shiny?
 
I can get the mirror edge to slow slice 45degree newsprint a bit rough but without tearing. With a bit a careful sculpturing the apex (i.e. abrasive shape near the apex but not directly blunt the apex), I can get a smooth slice of newsprint. Can't get it the push cut newsprint yet.
 
Too crazy an idea .... I hardly digest it :eek:

How to prevent abrasive embedded to the bottom of notch and blunting the apex?
 
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Chris "Anagarika";12942536 said:
Too crazy an idea .... I hardly digest it :eek:

How to prevent abrasive embedded to the bottom of notch and blunting the apex?
Click to expand...

Drill out the bottom with a 1/64" drill bit....
 
Chris "Anagarika";12942536 said:
Too crazy an idea .... I hardly digest it :eek:

How to prevent abrasive embedded to the bottom of notch and blunting the apex?
Click to expand...

Pressure downward when sawing, the apex cut deeper into the wood. In the freshly cut apex groove, there won't be much or hardly any loaded abrasive there. Hence I used the term 'nursing' the apex earlier. Also when pressure eased, the blade will get push upward ever so lightly that there will be a thin tiny gap at the bottom of the groove, there the apex itself will be safe from abrasion.. again 'nursing' the apex. Lastly angling the sawing motion will can also lift the apex away from abrasive, however you don't want to over doing that, since you want to shape the bevel face lead to the apex.

So as long as the rate of abrasion on the bevel face is faster than apex blunting, you can get a sharp apex.
 
Old Traf said:
@bluntcut

What type of wood, hardwood or something like poplar?

Old Traf
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Pine, poplar, basal, rubber... Wax maybe a bit soft & sensitive to friction heat. Pretty much any material has fairly uniform low abrasive texture and low memory (keep a notch without closing it instantly).
 
bluntcut said:
Pressure downward when sawing, the apex cut deeper into the wood. In the freshly cut apex groove, there won't be much or hardly any loaded abrasive there. Hence I used the term 'nursing' the apex earlier. Also when pressure eased, the blade will get push upward ever so lightly that there will be a thin tiny gap at the bottom of the groove, there the apex itself will be safe from abrasion.. again 'nursing' the apex. Lastly angling the sawing motion will can also lift the apex away from abrasive, however you don't want to over doing that, since you want to shape the bevel face lead to the apex.

So as long as the rate of abrasion on the bevel face is faster than apex blunting, you can get a sharp apex.
Click to expand...

Thanks. So two grooves, one for black & one for white.
 
Chris "Anagarika";12943504 said:
Thanks. So two grooves, one for black & one for white.
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Yep, one for each grit. I made a series of notches, then load compounds progression from fine to coarse - starting from the left notch loading rightward (hm is it an actual word?). So mirror progression, I work from right-to-left (coarse-to-fine), wipe blade between grit.

Black & white compound will cover 80% of what I need to do before progress to 6 or 3um (depend on alloy) to work toward 0.1um. Around 0.5um, where I focus on sharpness. Except for low alloy & carbon knives, I can get the knife plenty sharp after the white compound. After the black compound, my edge usually very toothy and sticky, but it won't slice newsprint at all.
 
A result of 12 minutes using this wood pinch mirror sharpener

experimental wip 52100 with a madrone burl handle (400 grit sanded). The mirror bevel is almost black looking
n6ej.jpg


Oops there are some dust on the bevel...
vhi2.jpg


I got this knife to push cut newsprint at 45* with grain - not super smooth but not bad. 8 minutes progression: black->white->0.1um diamond paste.
 
So there was no wire edge with the .1mic diamond? The sad thing is you probably get a better edge with wooden groves than I do on my best day sharpening...����sending you an email, this is another thought provoking thread. Russ
 
mycough said:
So there was no wire edge with the .1mic diamond? The sad thing is you probably get a better edge with wooden groves than I do on my best day sharpening...����sending you an email, this is another thought provoking thread. Russ
Click to expand...

The area near and at the bottom of groove will abrade away any burr & wire-edge. i.e. the pinch will remove burr & wire-edge and prevent burr/wire from forming. That was the reason why my previous post mentioned "didn't deburr". At 1um I detected a small wire-edge left over all the way from 320 grit sand paper sharpened. I spent extra 2 minutes on 0.25um to completely clean the apex. I test cut (10 minimum cuts) newsprint to confirm its sharpness & clean apex.
 
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