Yes agreed it would be great to have an outlined schedule from the factory once I approve the final prototypes (hopefully this month). I hope this post will catch everyone up for those who have not been following the threads and blog posts as closely, and also if you are interested in how things are made:
The turnaround time for the factory is longer than expected for correcting issues before the run starts but it is understandable given my quality standards and the unique aspects of bringing back 1980s production parts. They have been very patient working with me for going on 3 years now.
The factory timeframe I believe was based on expectations of standard parts requests and finishes - they didn't know how challenging this project would be for the nonstandard requests, nor did I.
The factory is actually building or adjusting their tooling for the special characteristics of this project. For example they are building a machine that curves the PCB to match that of the originals as there was no equipment that could delicately deal with PCB curving without damaging the copper traces. There is also tooling that precisely makes the inner assembly parts to the IBM Model F curve.
The parts requiring the most amount of work, the die cast original style cases, took 3 months for die casting, final machining, and powdercoating. Before then was maybe 3-4 months for making the molds and adjusting the powdercoating and texture.
The die cast case powdercoating process took months because the factory had to experiment with different paints and textures to match the original bumpy Model F 4704 texture - using standard powdercoating for the prototypes did not take long. The kind of texture and paint color did not exist (no Pantone color!) so everything had to be custom mixed until the colors were a perfect match to the 4704 case sample from 1988 that I provided. Then the powdercoating for some of the paint they tried did not stick well to the zinc so they had to switch to another type of paint. They ended up having to mix the custom made texture into the custom color powdercoat paint to get everything perfect.
The flippers and barrels were made from different proprietary materials (options had to be researched by the engineers) that were close approximations of the original plastic formulations that were never precisely disclosed back in the day (they work and the flippers perfectly convey the capacitive signal).
Pancake I will recap examples of first try prototype adjustments needed - the passed parts are listed in the OP "finished production" section:
- Original cases - powdercoating color and texture needed a few tries to get right and accurately match the originals (which they do now). Their earlier samples were very well made (and without much delay) to high modern standards but did not match the texture and color of the originals.
- Barrels - some measurement errors on my part of fractions of 1 mm caused the barrels not to interface with the keys like the originals; had to have them adjust the molds
- Keys - one critical dimension of the keys was not to my spec, probably 0.5mm off spec which made the keys not buckle consistently.
- Springs - they tried a number of materials; also the spring measurements were not accurate enough, under 1 mm difference but it is noticeable and could prevent a key from buckling
- Inner assembly plates - they were not to spec, maybe under 1 mm too large (the width of space between the top and bottom inner assembly plates. The first ones had holes that were too small to fit the barrels and some of the powdercoating was flaking.
In all cases I have held the factory to my standards and have rejected substandard parts.
Once they determine exactly what is needed, production is approved to start and there should not be much of a delay due to rejection of parts.
