Thread: Sharpness tests

Mark and Glen got it covered for ya.
You just need to know what works for you.
Above the arm, Hair test, or tree topping as its called, after finishing is a good one but it can tell you two things. One, You have microchips and it's pinching the hairs in half or two, you got an edge so sharp its finding the spot between the folicals and wedging them apart. (If that's the right word? I know its not spelled right.)
TNT at bevel set and TPT at finish plus a good loupe should tell you everything, but you need to know what its really telling you. And that takes practice. Non-consistency is normally from not enough practice. Keep at it and keep testing. You will find what works. Sure you can shave off an 8K, but I bet most of us would consider that a Pre-finisher.

I also use the thumbnail test for determining when the edge has arrived. From there, I use tactile feel on the stone and naked-eye observation augmented by an ~10x achromatic triplet loupe as to viewing chipping, scratch patterns, and relative polish. Sometimes, I also check to see if a few hairs are popping off the back of my hand towards the end of a honing progression, followed by the hanging-hair test after stropping. Otherwise, I've stopped checking via arm hair as I don't like walking around with patchy arms, particularly in summertime.

Originally Posted by Brontosaurus

I also use the thumbnail test for determining when the edge has arrived. From there, I use tactile feel on the stone and naked-eye observation augmented by an ~10x achromatic triplet loupe as to viewing chipping, scratch patterns, and relative polish. Sometimes, I also check to see if a few hairs are popping off the back of my hand towards the end of a honing progression, followed by the hanging-hair test after stropping. Otherwise, I've stopped checking via arm hair as I don't like walking around with patchy arms, particularly in summertime.

After the TNT at bevel set, I lean on an 10x achromatic triplet -- that is to say, an actual jeweler's quality loupe instead of an LED-festooned $5 pile of garbage from mainland China -- to keep tabs on progression progress and any unwelcome problems.

I cannot stress enough the tool quality difference between a typical Amazon $5 LED "poop-loop" and for example a BelOMO 10x achromatic triplet (< $40 usually but depends upon promos at the time of purchase).

If you don't mind viewing the world through a pseudo fog and feel like experiencing some minor eye strain, go China!

Agree with the folks above on the TNT. Nail that and the rest of the process is edge refinement and/or polishing. If you don't nail that, the rest of your efforts will be in vain.

I also use a test very similar to the one that Murray Carter promotes. I cannot in good conscience recommend it without caveats. It's a very good test but can also be very dangerous. Proceed with extreme caution.

All great points so far.

A few other pointers:

First tape the spine with some electrical tape. Second ink the bevel with a sharpie, now do a few laps on your King, you can easily see whether you are honing to the edge, this may mean using x strokes, rolling x strocks etc, also known as hoing gymnastics. If you are removing all of the pen, your good to go. Carry on using the same strokes until the bevel has formed the perfect apex. This is where the loupe comes in, look down the bevel and from the side, slowly angling your razor to see if there is any sparkles indicating that the bevel is not fully set. Once you can see that the bevel is fully set you can use other sharpness tests to clarify. Now that the bevel is set you can move onto your Norton to remove the previous stria that the King made, keep using the loupe to check that your on the right path.

If in doubt refer to post #4

I may be stating the obvious but also make sure to run the tests mentioned above with a razor that you know is not set, you have killed the edge. See how that feels, looks. The sparkle of the edge etc. Just to realize the contrast and how things change as the bevel is set.

I've tried all the tests, and have the nice, non-Chinese loupe, but what I usually do is set the razor aside after stropping and try it on a sideburn to cheek the next time I lather up as the real test. If it fails, it goes back to the stones. It it passes it might be my SOTD.

For me it’s the TNT after the 1k ts where I start, used to use cherry tomatoes all the time and still do when I have them but most of the time it’s the TNT and watch that water wave then I just move thru the stones, if the wave is not looking right I break out a loupe to see what’s going on.

After I have gone to final finish I Strop and do an HHT and 99% of the time it’s good to shave with but there are times when I’m just not happy and go back to the stones or I will sometimes just touch a pasted strop to get that last bit of edge

Those that know me, know I love the cherry tomato test.

When a bevel is set, every mm of edge should easily cut the skin of a cherry tomato with minimal pressure and a slight slicing motion. Any resistance and the bevel is not set.

The feeling should be 99% similar to a shave ready razor cutting the same cherry tomato

Originally Posted by Gasman

Mark and Glen got it covered for ya.
You just need to know what works for you.
Above the arm, Hair test, or tree topping as its called, after finishing is a good one but it can tell you two things. One, You have microchips and it's pinching the hairs in half or two, you got an edge so sharp its finding the spot between the folicals and wedging them apart. (If that's the right word? I know its not spelled right.)
TNT at bevel set and TPT at finish plus a good loupe should tell you everything, but you need to know what its really telling you. And that takes practice. Non-consistency is normally from not enough practice. Keep at it and keep testing. You will find what works. Sure you can shave off an 8K, but I bet most of us would consider that a Pre-finisher.

I prefer to think of it as entry level to a comfortable shave. In fact I've gotten rather lax on my honing, and at the moment the only straight I have giving me a comfortable shave from my rotation is the one I've been maintaining with a Franz Swaty barber hone that only gets an edge to around 8K. All the rest need a touch up, and I can't seem to be able to decide what hone set and method I want to employ...the down side (if there is such a thing!) of purchasing more hones than one man can use in a lifetime I guess? I've seen it said before that if you can't strop and shave at 8K anything you do beyond that is just wasted time because you'll be going back down to 1K or 4K when your edge disappoints you.

That said, the loupe has become my go-to ready checker. When I look at the edge and don't see any micro chips or burrs, the scratch pattern & polish matches what I expect to get out of the stone that I'm using, and I can flip the edge up and look straight down at the apex to see that it's completely joined heel to toe, then I know beyond a shadow of doubt the edge is as good as my hands can make it with that hone.If for some reason I get finished with the 8K, it looks good under the loupe, I strop and it doesn't shave comfortably - then I take the loupe out again and look the edge over to see what I overlooked during my inspections (or if I rolled the edge with poor stropping technique).

In my opinion, this is the most reliable test you can do because it relies on objective observation, rather than subjective tactile feel which is likely to miss things that negatively impact a shave. I'm sure every blade I've got would catch a thumb nail fine, and most could be dragged across one with no perceptible burrs or chips. To the thumb pad, they all feel razor sharp and even cut arm hair above skin level and pop it handily at the surface. Like the Germania Cutlery works I just picked up and tested did. Under a loupe, it seems to have the tiniest bit of microchipping near the edge leading to a slightly tuggy shave. Things my coarse mechanic's mitts with mostly dead nerve endings at the finger tips can't detect, but my face is more than happy to point out. Which doesn't mean that I don't ever try other tests, but ultimately the loupe is the arbiter of what is or is not ready to be taken to the ultimate test: the shave test. Your mileage may vary, some restrictions may apply.