MYRON - ALL iron castings from IH foundries were "sealed", you've seen the nice brownish-red paint inside CC rearends on non-machined surfaces. It's not actually red-oxide primer but similar. Think we've discussed it hear before.
When I was dealing with IH foundries expediting castings for FARMALL I'd actually call the sub-contract sealing companies to get daily shipments every day. Most cases the parts shipped to the outside painter were shipped the next day and were put into production, machined as soon as they were received in Rock Island. I'd talk to the production control people at the foundries so I'd know when the castings were poured.
From the time cores & molds were made & assembled, (they're Perishable, they tend to accumulate Water or condensation, and molten 2100 degree iron and water DO NOT MIX!) the castings were poured same day or early next day, then cooled. Most LVL castings were small so cooling time was hours, not DAYS like some castings I've been around, then castings were "Cleaned", risers & gates broken off, maybe a little grinding of parting lines, Wheel-a-Brate to remove burned-on sand. Then sent to the painter for sealing, normally a dipping process, parts were still wet when they were put into wire baskets and loaded on the truck for the 500 mile trip to FARMALL.
Truck gets to FARMALL the next morning, company trucks normally got preferential treatment getting unloaded. Hot parts that production was waiting for went to the first machining department, other castings went to storage out on the "river bank".
Depending on the type and how elaborate the machining was greatly effected the in-process time. Some work centers were terribly over-loaded, other parts got ran just to keep people busy. I was a Production Scheduler for nine-ten months @ FARMALL in 1977, handled secondary gear machining operations and some hobbing & shaving in a 4-machine work cell run by two people on each shift, 1st & 2nd shifts only.
There were times when parts needed to be reworked, which in some cases went to outside machine shops with special types & styles of machines, also when machines would go down, those operations were farmed out to outside shops as well. ALL this added time to the machining process.
There are ways to relieve the inherent stresses in gray iron castings without just letting them sit. There's "Thermal stress relieving", think heat-treating, heating to a relatively low temp then cooling in a slow controlled manner; Also vibratory stress-relieving, not very effective on pump machine bases I've been involved with.
I agree, IF you have time with cast iron, waiting some time to let the casting age is better than machining castings that a day or two ago was scrap iron. But that increases inventory, which costs money, takes up valuable storage room, decreases manufacturing flexibility, and will ultimately cause interuptions in shipping finished product to customers.
I would agree that there probably are some castings on every IH product that were produced weeks, even months prior to the actual build date of the finished product but I can not agree that it was because of trying to age castings to relieve inherent stress. There were ALWAYS HOT parts that were always hand-to-mouth from production. And other parts never seemed to be a problem, except for too MUCH inventory. Some jobs just plain run easier, better, faster than others. During most of 1979, '80, & '81 IHC LVL had to pay for at least ONE air shipment a DAY for the transfer cases used in 2+2 tractors to keep FARMALL running. You can bet THOSE castings never sat around.
In my years working at IH plants I actually found them to be DECADES ahead of most manufacturing companies with their adoption of leading, or BLEEDING edge concepts. They had process control, LEAN or Just-in-time inventory down to a science back in the mid-1970's. They were ISO-compliant 20 years before most companies knew what it was. They had their own satellite for over-seas phone calls, I got my own personal work FAX machine compliments of BF Goodrich in 1979, otherwise most communication was via phone or TELEX. IH's computer system for inventory/production control back in the mid-1970's was "State-of-the-art" for small company systems popular and used today!
