Thread: Sharpness tests

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.

The one test not in the Library and probably second in conclusiveness to the shave test, and easiest to perform is the visual test.

Just look at the edge, not the bevel, the edge, straight down on it with a bright light and magnification. Any shiny reflections are where the bevels are not meeting or chips.

At 1k there will still be some reflection but most of the edge should meet and be uniform. At 4k the edge should be very uniform and at 8k solid black, no reflection.

TPT and Hair test are very subjective, and the user must calibrate themselves to the test. Which means you need to learn what each test should feel like for yourself.

I use TPT and hair test to see if I am making progress and to test at least the toe, middle and heel. If so, I progress to a visual test and look at the whole edge.

Here is an old video/post by toxikwaste that demonstrates the test well

Toxikwaste sharpness test.

Since the OP indicated that his arm hair is difficult to cut, that also raises the question- Is your beard hair also difficult to cut? For many people, your arm hair and your facial hair will be of similar coarseness, but that may not always be the case. I know that for me, if a blade won't pop arm hairs at least 1/4" above my arm, I won't let that blade anywhere near my face. A properly set bevel should shave arm hair at skin level, but it has to be honed to a finer edge to pass the arm hair test, hanging hair test, or to shave comfortably. Although some people can shave off an 8K edge, that is not nearly sharp enough or smooth enough for me.

I have used various sharpness test: the arm hair test, the thumb nail test, the thumb pad test, and the three finger test, the felt block test, and the paper cut test. I realize that cutting paper does some damage to the edge of the blade, but it is a wonderful test for finding any chips in the edge of the blade. I use 15# Tablet paper or newsprint, not heavier copy paper. After doing the paper cut test, I always hone a few more strokes to correct any damage the paper may have caused.

One thing I have noted is that it is necessary to strop the blade before trying to cut hair. Otherwise, the chances of cutting hair are slim.

Great answers. You have to find out what works for you. Try what others have said. But it takes experience. IMO you should be able to cut arm hair pretty easily bevel set and a quick strop or two on whatever jeans or shorts you may be wearing.

Also if you are honing with a bevel trailing stroke, you might have a burr that's preventing the cutting of your hair.

For me arm hair, reflection of the blade, and loupe are my indicators of success. The shave is the measure of success.

Originally Posted by CoreyW

Also if you are honing with a bevel trailing stroke, you might have a burr that's preventing the cutting of your hair.

As a rule I do not use a bevel trailing stroke while honing a symmetrical grind straight razor. I may when almost finished on a stage in honing do one or two trailing edge strokes followed by a couple of normal edge leading strokes.

Bob

I would suggest finishing on a stone higher than 8k. 10k or 12k would give you a better edge. The best test after a finish on a 12k is show the blade to your arm hairs and several will immediately fall out, petrified of the keen edge! Maybe.

"Off the 8K the arm hair cuts easier, but never above the skin.

Is it necessary to use something like chromium oxide to finish a razor. Using stones doesn't give consistent results and at times not sharp enough."

Joe, how is the shave?

Yes, with practice one could get a very shavable edge off an 8k stone. But Chrome Oxide is at least 30k and 20-30 laps can be done in minutes and will produce an excellent edge and shave.

I doubt your hair that is the issue, as said you have to calibrate the level of sharpness to your edge and your test samples, skin for touch test and hair for hair test.

As your level of honing improves, your edges will get sharper and more comfortable. It is not as easy as rubbing a razor on a stone and getting predictable results. Chrome Oxide is but another tool that has been used successfully for hundreds of years. If that is what it takes for you, that is what it takes.

Make sure, the bevel is fully set, and that you are removing the stria from each of the previous grits. Both common problems for edge issues.

Try adding one layer of tape and doing 30 laps on just the 8k, see if just that improves the edge.

I suspect it is technique, Post some photos of your razor and edges. Guys have posted some good bevel images using a loupe and cell phone recently.

Thanks to everyone for replies. I don't have a camera at this time. The razor I am trying to hone at the moment is: Blossom, The W.Bingham Co, Cleveland, made in Germany. I used a marker on the razor to check my stroke and to see if the bevel was being set.

I used swooping and rolling x since it has a slight smile. I spent quite a bit of time on this using light to very light pressure, but it is not easy to get sharp. It passed the TNT, but after going through the progression: king 1200, Norton 4/8K all I got was a razor that could take off the lather. The bevel looks close, but can't understand why this is taking so long. This razor is fairly light, 4/8 razor. I have a 11/16 razor with a smile and I got that sharp enough to get a good shave.

I have some 1 micron lapping film, but with this razor it doesn't work well: it sticks and feels like it is catching on something, so stopped using it. On my other razor I don't have that problem.

I do have a hasting's triplet, but need to learn how to use it better.

Joe