Here's what Terry was referring to.....
It's a machine designed to service spark plugs back when they did such things rather than replace them as we now do.
Not sure when this was made but I'm guessing sometime in the 40's to 50's.
The plug was inserted in a hole that used a rubber skirt to seal the threaded part of the plug. It's covered here by a protective arm that swings out of the way seen at the top center. The dark round object at the right center is a rubber skirt with a different size hole in the center for smaller or larger plugs depending on the one in use.
Once the plug was inserted if you wanted to clean it you'd depress the tab marked "abrasive blast" and very fine powdered grit would be blown on the electrode end which would clean off all the old carbon and other deposits. Once done with that pressing the "air blast" key would blow pure air that would remove all the abrasive just blown on it.
After the plug was cleaned you could insert the plug in either of the fittings (depending on plug size) seen in the center, swing up the black arm to connect it to the top of the plug and then rotate the black knob on the left to send voltage through the plug to test it and see if there were any cracks in the porcelain. This machine, though dirty still performs the cleaning function remarkable well. I have not tried to send any voltage through a plug yet. When I get a little more time I'll post pictures of everything with a plug being serviced. Just wanted to get this posted.
And there's more ........... on the way if you can stand it.
Thomas