This one was tough to track down, it was mixed in with a box of old tractor wrenches so I assumed that's what it was. No makers mark, but a very clear part number of TKLXI-B. After Google sent me down the military path I finally found it. Ordnance maintenance adjustable spanner, 75mm recoil cylinder, M4 (Sherman tank) and M6 (B52 Mitchell). May be post war as that 75mm design was still around for some time. 11-1/2 long and weighs in at a pound and a half. This is my strange find for the week.