Extremely toothy edges right from the sharpmaker

T

Threethreethree

Joined
May 30, 2013
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117
Hi there

I recently lapped several 204 rods to use as a hand stone with really great results ( i had my first HHT edge right from the stone without stropping using the white lapped rod if that says something ).
I noticed you can fine tune the stone grit using finer or coarser abrasive to lap it, as if you cut grooves in a file to make the 'grit'.
So naturally i had to try this on the edge of the medium rod to enhance cutting and decrease the grit rating, this works REALLY well, i used a well worn lansky extra coarse diamond and rubed lenghtwise and avoided back and forth to not dish the corner using wd40 then i swiped my Police3 2 passes per side at 40 deg, the microbevel is starting to be wide (approx 0.5mm) the edge formed clean without any burrs when using light pressure and slow pace it's incredibly toothy and you can nearly see the jagged appex, it push cuts newsprint noisily, it can shave and cut hairs above skin, whittle beard hairs yet not really treetopping arms hairs yet.
It's really interesting, i didnt try to remove lot of stock with it yet as i only use my 204 to put microbevels but i have the feeling it has some serious capabilities, i noticed the 'grading effect ' doesnt last really long but you can renew the grooves with a couple of swipe with the XXC dia.
I marked my rods to keep 'grading' the same corners so in the end they will be flatter and will not work anymore on SE yet they will have a slightly better contact area on regular edges leading to a better cutting action, less burnishing thus less burrs.
 
That's interesting. I gently rubbed the corners of mine with diamond plates to remove years worth of metal that couldn't be removed with conventional means. I did notice that they cut really well after doing that. My question is whether you can unclog them with Barkeeper's Friend instead of using diamonds again? Also, will the rods wear out quickly?

Good sharpening,
Dave
 
Barkeepers friend or oxalic acid will dislodge metal but wont renew the abrasive, and yes lapping/ rubbing them will induce wear quickly, i rubbed my medium rods maybe 30 times and i feel a sharp corner already instead of the radiused edge, so use this with caution.
Replacement rods are rather cheap though and with the increased cutting rate that is a fair tradeoff and they give a MEAN edge, to the point i will simply stop using finer grit on most of my knives except the one i expect to behave like scalpels.
If you use worn and dirty rods since a long time you will be shocked how they can cut if you 'grade' them yet they wont flip flop burrs like they used to.
 
The diamonds cut a grind pattern into the stone that will act like a file (speculation). You might even notice a difference in grinding if you rub the plate at planned angle(s) across the rod, making the cuts in the ceramic like the patterns on different file types or lengthwise like a butcher's steel. I've considered doing some experiments like that with my Fine block, but don't have any XC or XXC diamond plates.
 
Yes it's pretty much like a file pattern, i did experiment elliptical moves when surfacing the flat surfaces of the rods and noticed they leave grooves in circular patterns that blackens more when you sharpen it is really interesting to note that when you grade white rods that way they cut faster yet still yield a good polish.
On the other hand the finish you get from the surfaced medium corners is that coarse that you really have to only do draw cuts, even if it shaves and pushcut PB paper you feel the orientation of the teeth in every applications and it can impedes some way of uses yet the slicing aggression is really surreal and so is the edge retention.

I ordered a gatco tri seps ceramic handeld triangle ( essentially a half sized 204 medium rod ), a Spydie ''simplestuff'' medium and a medium bench stones, and i need to grab something really made for lapping like an atoma 120 and i'll dig further in the dark side of the toohy edges.
Oh and i ordered another Endura ffg (purple vg10) to make good measure and to be a test slave.
 
I wonder which is more important - cutting grooves into your hone can do (at least) two things relating to files (which is what hones are, afterall):

- A) the "peaks" increase pressure of the hone-abrasive on the object being ground
- B) the "valleys" collect material well below the cutting-surface of the hone, allowing it to cut without as much clogging

I suspect A isn't really that helpful, you could always just use the coarse lapping-stone itself or simply apply more pressure on an un-'grooved' hone, and there is already the risk of putting too much pressure on a section of edge and tearing it off in un-even fashion.
But B - a fresh hone vs clogged - makes an enormous amount of difference. It can also be that, like lapping a regular stone, it isn't so much the grooves allowing for increased cutting as the renewed surface - sharper abrasive particles with more bite than the previous worn-surface. *shrug*
 
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