Does anybody recognize this footstock?

[wildcatter]

So I bought this B&S #13 grinder and one of the accessories is not for a Brown&Sharpe. I have no idea what it fits. I appears to be a footstock for a grinder but there are no markings anywhere. It is bluish -grey in color and very heavily made. The center seems to be a Morris taper but I have no tooling to check. It is very close to B&S #7. There is a lever for quick retraction of the center(spring loaded) and an aluminum dust cover with a left-hand thread. If I can find out what it fits ,maybe someone can make use of it. Thanks for any help!The center in it is a shop made item.