340 casting "revision numbers" check in
And did you guys know that pointer with the dots around it is the casting hour marker. Work shifts were 8 hours, so if the pointer was at the first dot from the 12:00 position that mold would have been made in the first production hour, pointed at the second pointer the mold would have been made in the second production hour and so forth. There should also be a second marker or pointer on the casting to indicate 1st, 2nd or 3 rd shift. Although some foundries used a screw whose head would form in the mold and show in the casting. A standard straight slotted screw for first shift and a Phillips head screw for second shift. The time between the mold being made and the iron being poured in is typically in the minutes. Molding lines where automotive blocks were cast would run at a rate of 80 to 100 molds to hour. Molding lines where cylinder heads were cast would run at rates of 200 molds per hour. Simple castings like flywheel housings and brake drums where there were no cores to be set could run at perhaps 300 molds per hour.
The cast dates and shift markers were typically very accurate, as they were set once at the start of the shift. The hour markers were less accurate as to change the hour marker the molding machine had to be stopped, locked out, a person would go to the pattern and move the pointer, then the molding process re started. A good crew could do that in a minute, but those molding units were held to high standards for uptime and for most molding unit foreman, changing the pointer was not the top priority.
