Nothing is standard in China, one person has this idea, another that, and money is so important to them you can never trust tool wear. They work in a very low pressure environment with machines scraping and screeching and to them its business as usual - their way of putting in the extra effort is putting plants and flowers all over the machine shop.
I went through this entire line of thought today, thanks for the pointer I forgot to check for linear interpolation. That was a big no in school too. However the bores align fine on most parts.
Yes Chia I know engineers all too well.
Lots of good reasoning here, I told the boss line boring might be an option.
But had a conference call today and he basically wrote off the challenge of temperature deviations, and the local boss (even though he doesn't have a clue) said he would allow me that much (what much?) as though I was being held to some unknown standard in his head.
Big boss wants to pour a grey iron fixture and use quick change tooling and for me to overhaul the entire production process instead of just producing 6 good parts, which is good. Foundry and pattern labor are basically free and he wants to really impress.
I think the final critical part here is once the part is machined, to insert a dowel pin and use a dial to center the spindle on that location to double check the distance from the bore.
.005" deviation on a diameter of 19" is more than a temperature problem. I also checked the reports this morning and there was no pattern or consistency to the hole locations, they appear completely random.