Small knife jig adapter for very small knives

[Elden]

Did the tin hold the blade rigidly enough so that the blade edge didn't move up (change angles) when pressed against the grinding wheel?

[Herman Trivilino]

I think he means did the knife blade angle stay constant.

[Elden]

Leave to the pros to say what I mean!

[grepper]

No problem with the blade moving in any direction.  It's held tightly against the jig and the handle helps with keeping it stable too.

You have to keep in mind that this is a very small knife, so very little pressure is exerted on the blade during sharpening, but it was surprisingly stable anyway.

Like I mentioned earlier, with larger knives with a larger tang, there could be maybe 3 different sizes  of add-ons that would cover about any knife that you could not place directly in the jig. The larger the tang, the larger the add-on and the more tightly it could grip the tang.  I suspect that with better materials and some engineering, a knife could be gripped very firmly.

I had freehanded the little knife on the Tormek prior to sharpening it with this advanced, highly scientific and technical extreme jig system, and had gotten it pretty sharp.  Now, it's even sharper.

[Herman Trivilino]

I had freehanded the little knife on the Tormek prior to sharpening it with this advanced, highly scientific and technical extreme jig system, and had gotten it pretty sharp.  Now, it's even sharper.

I'm having trouble judging the sharpness.  What's your method?

[grepper]

Well, huh.  There is the hanging on the fingernail at a very small angle.

Pressing, with little or no slicing downward on the edge of paper and carving gentle curves.

Various paper is much harder than other paper.  Try hanging a piece of paper both in both directions.  Take a piece of 8 1/2 x 11 paper and hang it vertically holding it from the 8 1/2 in side at the top and slice down through the long edge.  Then try it the other way by holding the long side on top and slicing through the vertically hanging 8 1/2 in side.  Amazing how different cutting with/against the grain of various paper is.

Try some of the thin, shiny inserts that come in newspapers. Some are very hard to cut against the grain.

Try paper towel for a real challenge.  Grab on to the top and stretch a small portion between your fingers and try to slice downward.  Some paper towels are very tough to not tear whist cutting. 

Get a long single human hair.  Hang it vertically from a pair of pliers.  Chop it in half with a Kung-Fu slice.

Get a commercial razor blade and do the same so you have something to compare your artistry to.  If you can say they are similar, I'd say it's razor sharp.  Scary sharp!

The ultimate: get a medical scalpel. Be careful with it.  They are _damn_ sharp.  Much sharper than a razor blade.  Do the same tests and compare your edge to a scalpel... Good luck!

Oddly, get a rotten tomato.  Try to press down through the skin with little slicing... Good luck!

By having a known quantity for comparison you can say it's razor sharp!  It's scalpel sharp.  It's SCARY sharp! 

[Jeff Farris]

Tests of sharpness:

Does the edge catch on your fingernail?
Will it shave calloused skin? (dangerous test if you're not fairly confident in your edge and your dexterity)
Does it cut standard #20 printer paper without leaving a ragged edge?
Can you change direction of the cut in the paper whilst cutting?
Can it cut across the end grain of a piece of open-grained soft wood without tearing? (balsa and fir are best test)
Will it easily shave the hair off your arm? (no spit, no pressing, just glide)

[Ken S]

A not so macho alternative to the thumbnail would be a plastic pen.  (Not orginal with me; I forget the source.)

Ken

[Rob]

Tests of sharpness:

Does the edge catch on your fingernail?
Will it shave calloused skin? (dangerous test if you're not fairly confident in your edge and your dexterity)
Does it cut standard #20 printer paper without leaving a ragged edge?
Can you change direction of the cut in the paper whilst cutting?
Can it cut across the end grain of a piece of open-grained soft wood without tearing? (balsa and fir are best test)
Will it easily shave the hair off your arm? (no spit, no pressing, just glide)

If this isn't a classic for the sticky then I don't know what is....this succinct, punchy useful bullets is exactly whats needed. People have a clear set of tests they can perform and relate to instead of esoteric measures of sharpness like....."scary sharp". Of all the euphemisms for sharp, that has to be the most loathsome

[Herman Trivilino]

A not so macho alternative to the thumbnail would be a plastic pen.  (Not orginal with me; I forget the source.)

Ron Hock.  I read that just last night.  He also mentions running the edge along the end of your thumbnail, with great care of course, applying only the slightest force.  Any flats, nicks, or imperfections in the edge will telegraph through and you'll feel them.  I tried this and it works well.

[Ken S]

Thanks, Herman.  I hope you are enjoying Ron Hock's book.  He also has an interesting blog on his website.

Ken

[grepper]

Oh no! Another thread on what is sharp!

I think the question, what is sharp, is interesting.  Ask anyone to name something really sharp, and  a razor blade is often the first response.  Yup.  A razor blade is rather sharp.

So if someone asks if their knife is sharp, without the benefit of a scanning electron microscope, this a great way to explain it:

Get a new razor blade and perform all of the standard home sharpness tests that have been described above.  Then try the same tests with the blade you just sharpened.  How does their cutting performance compare?  That gives a very good idea of how sharp something is because the sharpness of a razor blade is well understood.  Everybody agrees that a razor blade is pretty sharp.

If your knife can cut 20# printer paper against the grain smoothly, that's pretty sharp.  Try facial tissue or paper towel.  Get a "feel" for various paper products against the grain. There are many that are much more difficult to cut cleanly than printer paper, requiring a much sharper edge.

Sharp is such an ambiguous term, but in comparison to other blades it can at least be put into understandable perspective.

I think it all depends on what folks "think" is sharp.  Obsidian scalpels used in ocular surgery, or plasma polished diamond blades can have edges hundreds of times thinner, (sharper), than a fat, "dull" razor blade.  Now, I'll bet those things are, (rhymes with very), sharp!  

http://www.finescience.com/Special-Pages/Products.aspx?ProductId=296&CategoryId=56

[Herman Trivilino]

Thanks, Herman.  I hope you are enjoying Ron Hock's book.  He also has an interesting blog on his website.

Yes, Ken, thanks for recommending that book.  I enjoyed the section on the metallurgy of steel.  Reminded me of my grad school days and our experiments with silicon.

[Herman Trivilino]

Get a new razor blade and perform all of the standard home sharpness tests that have been described above.  Then try the same tests with the blade you just sharpened.  How does their cutting performance compare?

Hey grepper, do you notice any difference in the sharpness with the edge angle?  I would think that the smaller the angle the sharper the edge.

[Rob]

Leonard Lee has a thing or two to say about that which makes really good sense.

Bottom line...for all kitchen knives that are destined to slice flesh and veg only.....10 to 20 degrees included angle.

For those destined to chop through bone or heavier duty stuff....much greater..30+ right up to cleavers which were discussed recently