Sharp Test ? on 320 grit Stone

[linuxology]

Wondering how sharp a knife should be coming off a 320 grit stone? What test would be valid for rating the edge? It seems one should get it as sharp as possible before moving onto the next phase.

 

[HeavyHanded]

Will depend on the steel, abrasive type, edge angle. For some stones a rated grit of 320 might be just sharp enough to dryshave some facial stubble.

In general I like to see it shave armhair and crosscut newsprint even if a bit noisy doing so.

On some steel/abrasive/angle combinations it might be just good enough to shave some armhair while missing some and snagging others, and be just good enough to shear or drawcut newsprint.

If I'm using it in a progression I only am concerned that the edge is fully reset at that grit value - good scratch pattern and bur heel to tip, deburr and on to the next. I might check for sticky or just visually confirm and go - no cut test needed.

If I'm stopping at that finish I'll expect performance as described.

 

[Obsessed with Edges]

My basis for comparison to '320' would be either the Fine side of a typical hardware store stone (SiC, AlOx) or a 325-mesh diamond hone (DMT 'Coarse'). In either case, an edge coming off of these should be easily sharp enough to cleanly slice phonebook pages, newsprint or magazine/catalog pages in half in one swipe, perhaps with a little snagging due to burrs. And if the finishing technique is good from the stone, any burrs left should be minimal enough to remove on bare-leather stropping, most of the time. As mentioned above, some intermittent/catchy shaving might also be possible with such an edge. It should easily be sharp enough for any typical EDC tasks, like opening packages, boxes, mail, etc., cutting rope, kitchen chores (meat, veggies, fruit). In a nutshell, it's a good or even excellent all-around finish for a knife edge.


David

 

[bucketstove]

Wondering how sharp a knife should be coming off a 320 grit stone? What test would be valid for rating the edge? It seems one should get it as sharp as possible before moving onto the next phase.

Hi,
What is the next phase?

It should shave and slice newspaper or phonebook paper cross grain without problem.

If its your final stone,
It should shave and push cut phonebook paper cross grain at 90 degrees in all dimensions

• 320 grit stone , push cut newspaper at 90 degree, 45 tip left , 45 tip up
  Normark EKA 12C27 : optimal edge geometry for slicing hardwoods (norton economy fine edge) - CliffStamp
• only shows newspaper slicing but it will shave
  Extreme low grit sharpening : 24 grit nubatama - Cliff Stamp
• shows arm hair shaving and newspaper push cut at 45 degree tip up
  Knife sharpening : 36 grit dressing stone - Cliff Stamp

 

[David Martin]

That level grit is a good stopping point for a knife edge to do general cutting. i.e. meats, vegetables, rope, cardboard, ect.. DM

 

[DeadboxHero]

Will depend on the steel, abrasive type, edge angle. For some stones a rated grit of 320 might be just sharp enough to dryshave some facial stubble.

In general I like to see it shave armhair and crosscut newsprint even if a bit noisy doing so.

On some steel/abrasive/angle combinations it might be just good enough to shave some armhair while missing some and snagging others, and be just good enough to shear or drawcut newsprint.

If I'm using it in a progression I only am concerned that the edge is fully reset at that grit value - good scratch pattern and bur heel to tip, deburr and on to the next. I might check for sticky or just visually confirm and go - no cut test needed.

If I'm stopping at that finish I'll expect performance as described.

^ great info