VEX seems to be shifting away from all of the low strength options, and leaning more into the high strength accessories. Gears, wheels, and more are receiving the “low strength” → “high strength” makeover. It’s unlikely that these gear sizes will receive low strength options.
VEX released high strength gears after they released the low strength gears, then made a V2 of the said high strength gears, not revamping the low strength gears at all. This, as well as all of the following product changes recently, have led me to believe that VEX is encouraging everything high strength. Following this theme, it seems unlikely that VEX will release low strength gears of the 24, 48, and 72 gears.
You might have noticed that the round bore is nor only round, but also different color. I.e. different metal. That’s a very important detail. The round bore could be made of brass, but most likely it’s made of “bearing bronze”, a special composition metal used, well, for bearings. You most likely have a few bronze bearings in the PC you’re reading this message on, they are often used in computer fans. And about everywhere, when you need a bearing, but can’t really go all the way with ball bearing.
Bronze, an alloy of copper and tin, is a common bearing material because it is hard, strong, and wear resistant. When making a sleeve bearing, which is a “sliding bearing” rather than a “roller bearing”, it is important that the bearing material be slightly softer than the shaft material, so that the wear will be in the bearing rather than the shaft. Bronze has an additional property that it doesn’t gall (or stick) to the steel, which would pull of microscopic bits of material during wear. Rather, it wears away very slowly (especially if lubricated a bit), while offering a low coefficient of friction against the steel shaft.
(To learn more, you can take Materials 101 class at Monroe County Community College )
and as an added bonus, you can tell if it is a square bore or round bore by just looking at the color, like the square/round high strength shaft inserts
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