What is this tool?

[vdotmatrix]

It has an abrasive centerpiece….no idea what it is for.

 

[4xdog]

Knife sharpener. I asked the same question here years ago after finding one in my late brother's stuff!

 

[RTM]

Knife sharpener.

And so much more. I especially like them for garden shears. If there's a narrow groove down the back side, it's designed to do fish hooks as well.

You're basically just a small surface sharpening stone that you can carry in your shirt pocket if you reverse or retract the abrasive

 

[Rusted Nut]

The other end of abrasive rod is probably tapered, used for sharpening serrated blades. Unscrew the knurled sleeve, pull rod out.

 

[Beerhippie]

A diamond abrasive knife blade killer. Don't use it on good chef's style knives--it will hollow out the profile of the blade, leaving you unable to cut through stuff on a cutting board.

For things like butcher knives and hunting knives you don't cherish, it's fine.

--highly opinionated knife owner.

 

[darkzero]

As said, a general purpose knife sharpener. Most have a D sahped rod. A flat side & round profile on the opposing side. I have one that also had a groove on the round side. The groove is for sharpening fishing hooks, supposedly. They don't work that good but having one in a tool kit for use out in the field in a pinch can be handy.

 

[vdotmatrix]

Yes thank yall! I found the groove for sharpening fly hooks! What a find!