All About Pocket Knives

I learned something interesting yesterday that relates to the frequent question asked here on AAPK, are those handle slabs on my old knife bone or not? A fellow was telling me how he learned this from an old guy that collected knives for decades. It is a static electricity test. The way I tested this at home today to see if it works is like this. As you can see in my photo I had an orange piece of paper so things would be more easily visible, then I tore some pieces of tissue paper into tiny pieces (make sure your hands are clean and dry before doing this). Then I took a knife that I knew to be of composition (not bone) material and stroked it against the back of our cat Sophie. This built up a static charge on the handle material of the knife. I then carefully brought the knife down toward the pieces of tissue paper WITHOUT TOUCHING THEM and WOW, some of the pieces jumped up and stuck to the knife handle.Everyone who has animals in the house is familiar with the static charge that builds up when you stroke them, especially during the drier winter months indoors. Bone handles will not accumulate a static charge like synthetics will and it is this principle that makes this work. I would be interested in seeing what results others of you who are reading this get when you try it.

Very neat ! I will give it a try when time permits and see what happens.
kj

It's a lot easier for me to pick up my 45X microscope and just look. Cost me 2 bucks on ebay.
BUT if you don't have your microscope with you or don't have one, that sounds like a nifty low tech way to differentiate between bone and synthetic.

Thanks for posting this info, a very useful tip.

I don't have a cat but I have an old woman here; would that work?

Thanks. Wool and Silk will do it too.

tongueriver wrote: ↑Sun Mar 21, 2021 8:28 pm I don't have a cat but I have an old woman here; would that work?

I would certainly give it a try, Cal. Your results may vary.

jerryd6818 wrote: ↑Sun Mar 21, 2021 6:59 pm It's a lot easier for me to pick up my 45X microscope and just look. Cost me 2 bucks on ebay.

45x microscope - Labeled.jpg

Comparison Bone (haversian canals) vs Delrin.JPG

BUT if you don't have your microscope with you or don't have one, that sounds like a nifty low tech way to differentiate between bone and synthetic.

Jerry, that is a lot cheaper than having to maintain a cat. lol

Or an "Old Woman"

: You guys crack me up.

In my line of work static charges can be either a blessing or a curse. If I am laying down gold or silver leaf I pick it up by using a "gilder's tip"which is a squirrel hair brush about 3 inches wide but very thin.I rub the bristles across my hair to build up a charge and then carefully lift up the leaf out of the book it comes in and very carefully lay it on the glued surface. I then smooth it out with a cotton ball.The leaf sticks wherever the adhesive is and rubs off where it is not.
However if I am doing art work on a plastic surface(fiberglass;ABS;etc.)after I clean the surface I have to go back over it with a damp paper towel to de-static the surface.Otherwise when I go to lay down the paint with a brush the static draws the paint off the brush hairs and deposits them exactly where I DON'T want paint;much like the OP's pieces of tissue.
Bone is usually pretty easily discerned by looking for the Haversian canals but some smooth bone can be deceiving.The static test will definitely be an asset on that type of bone.

jerryd6818 wrote: ↑Sun Mar 21, 2021 6:59 pm It's a lot easier for me to pick up my 45X microscope and just look. Cost me 2 bucks on ebay.

45x microscope - Labeled.jpg

Comparison Bone (haversian canals) vs Delrin.JPG

BUT if you don't have your microscope with you or don't have one, that sounds like a nifty low tech way to differentiate between bone and synthetic.

Yep, works like a charm. They also make a 60X. I think it was $5.95