Spot the Tool

I'm a sucker for cheap tools. Can you identify this one? It looks like a tiny hammer with a hollow head and some abrasive on the top face.  

  

Workmanship?

 

It’s a grinding stone dresser.

A tool I use a lot is a bench grinder. This has two stones wheels (coarse & fine) for grinding metal. The stones had become rounded with use. They still grind ok but not for things that need a flat face like sharpening drill bits. The dresser grinds down the grinding stone.   

I actually bought a pair of new wheels but saw this for £1.99 so thought it was worth a try. I wasn't hopeful. The head and shaft are far from a right angle indicating that this is not a precision made item. Quality dressers use diamonds set in tungsten carbide but I doubt I got that for the money.

 
Surprisingly it worked!

I didn't use a lot of force because I thought that this would destroy the tool. But light pressure produced a fair amount of dust as the wheel was ground down. 
 

Using the tool

  

Re-shaped grinding wheel

Protection was needed