Thanks for your detailed review XMIT. Here are my notes:
Key texture - the key top is more textured on purpose! Keys from newer molds that haven't seen much usage (like the new molds for this project) as well as keycaps that haven't seen much usage have a fresher texture. My NIB Model F's have far more key texture than my other (used) Model F keyboards from around the same time. Once millions of shots have been made from the molds the texture wears down, but the factory can re-texture the tops every now and then as part of maintaining the molds.
The keys are a replica of the one piece F122 and XT originals in my collection. IBM's keycaps varied over the years and I have interestingly found the later production keycaps (including those on many F107s) to be not as good as the 1983-1985 period IBM originals.
IBM's later 4704 and other Model F caps had noticeably different fonts and had looser quality control - thinner in stroke, more condensed, and less nice looking in my opinion. The project's goal for the aspect of dye sublimation was XT quality fonts, not reproductions of the 4704 fonts (even though the rest of the project is 4704 repro!).
The filled in hole inside the key is possibly a later design by IBM compared to the hole. (The hole is for the ejector pin of the mold!) The earliest keys in my collection have a hole for the most part, as well as the 4 circular designs on the bottom edges as shown, so I put it there. IBM's key designs varied across production lines, across time, and possibly across their different manufacturing facilities.
They probably stopped that design because it puts a lot of stress on the one ejector pin during injection molding. During injection molding of the keys, one of the ejector pins of the most-used type of key (1U) actually broke and needed to be repaired.
In summary, all of the legends are accurate to the 1984 F122 and XT caps in my collection and the keycap part tolerances are within my required +/- 0.1 to 0.2 mm. Forum member Zed did an excellent job recreating the fonts exactly from high resolution scans I sent over.
Regarding the stabilizer inserts, agreed it is best to use the project inserts with project keys and non-project inserts with the non-project keys. The inserts are also more difficult to remove. As many of you probably know, given PBT being more difficult to work with due to shrinkage, getting the PBT parts just right so there is not too little, and not too much space between the key post and inside of the stabilizer insert proved very difficult a few years back, but getting the insert working with the new project keys was the priority over getting a looser fit like the originals.
- 2018-02-27 Key Molds and key mold repair.jpg (174.07 KiB) Viewed 10433 times