So the 10m of 2.4mm chain arrived yesterday and it looked and flexed the same as the small sample of the stuff I've had since 2022.

After seeing it, I went back to the dark 3.2mm chain and tried to see if I could scrape anything off the single crushed ball and I was actually able to get a tiny fragment of coating off, revealing the stainless steel below. It was then entirely possible that the reason for the large tensioned turning radius was due to the coating on the linkages. The 2.4mm chain slides on the linkages when on the bend, which doesn't happen with the dark 3.2mm. Thus, I found and bought another 3.2mm chain:

This literally-brand-new chain is the brightness I was expecting and it has a spacing of 4.55mm. It also goes around the OD 8.4mm pen-like scribe barrel much better than the used-like-new chain. This is good news since I was hoping that I could use 3.2mm chain for the #T^2 Tiles [gd0095] because, while it's twice the price of 2.4mm ball chain, it holds 20lb / 9kg more (source: www.ballchain.com), it should better resist slipping on the sprocket and it can be spliced into a closed loop.

It does seem that I should opt for a OD 8mm ID 5mm silicone tube instead of 7mm OD, wether I'm using the 2.4mm or 3.2mm. I still think the 3.2mm looks and feels better, so I'm going to revert in the CAD file. 

Parameters of this new SourcingMap 3.2mm chain:

• 3.20 - 3.25mm balls, most commonly 3.23mm
• 0.77 - 0.80mm linkages, most commonly 0.79mm
• 4.55mm spacing