Replies

1. 
   rob_ss | Oct 22, 2023 04:37am | #1

   You can measure sharpness objectively with a machine but for all practical intents and purposes, if it will shave hairs easily (as opposed to cutting the odd one after a few goes) then it is sharp enough.

   Other options for testing:

   - will it slice paper cleanly?
   - plane a little end grain (softwood is best)

   For me, if it works well, it is sharp enough. Why not watch JKM's video about it.

   https://www.youtube.com/watch?v=GBjiEmN5HzA

   https://www.sharpeningsupplies.com/Edge-On-Up-Professional-Edge-Tester-P1563.aspx

1. 
   lat_axe | Oct 22, 2023 08:22am | #3

   Shaving the arm hair - it shows a sharp blade but a blade with a slightly raggy edge will also grab and part the hairs. A raggy edge soon crumbles when used to plane the wood rather than the hairs.

   Some papers cut much more easily than other papers. The question then becomes: how sharp is my paper-cutting blade and is it really sharp enough for the wood. Also, you're only testing a tiny cross section of the blade - one as wide as the thickness of the paper. You might not have got the whole edge sharp.

   The planing of the softwood end grain seems the best test, as softwood end grain will deform rather than cut unless the blade is truly sharp. A raggy-sharp edge will also show up on the softwood as a less than glassy resultant surface. You can test the whole blade edge with just two to four cuts on different parts of the blade.

   But as John C2 mentions, the true test of, "Is my blade sharp enough" is to use it to plane or chisel the wood you want to plane or chisel, to see the results.

   On the other hand, when new to sharpening, a test can serve to avoid a blade that will, when you use it on your valuable workpiece after "sharpening" it, do some damage. So, rather than slicing a bit of softwood end grain, take a full shaving from a scrap piece of what your workpiece is made of. Is the shaving a fine ribbon leaving a smooth surface on the wood with no tears or tramlines?

   Lataxe

2. 
   john_c2 | Oct 22, 2023 06:15am | #2

   Testing is a waste of time. But honestly, so is the 600 stone, and going back and forth to a buffing wheel, which is rounding your edges, and forcing you to go back to a grinder or coarse stone.

   1,000, 4,000, 8,000. Back to work. No testing. Less than a minute.

1. 
   Spelch | Oct 24, 2023 06:35pm | #4

   Agreed across the board , John C2. You nailed it. I wouldn't even use the 1000 for a maintenance sharpening. 10-15 seconds each on the 2 finer stones and back to work.