Savage wrote:Frigid here is a sunny day there. My guess is it's something to do with the tempering of the metal, not just how reinforced it is. You may need to try ordering from one of their sites, they might be distributing a better style, or a different type of metal.
Aluminium (Not aluminum) preforms a lot like nickel in the cold; it falls apart. It's also an extremely cheap metal. Your gearboxes very well may have some mixed in to cut production costs. So, even a tiny flaw mixed into the entire gearbox is going to mean a weak point.
Well, while a lot of what you said is logical, a lot of it is very wrong.
Alloying small amounts of a material into another will increase the overall strength. There are very, very few instances in which this isn't true. And aluminum/iron/carbon/nickel all alloy together, increasing strength.
While you are correct in the idea that 'tempering' of the metal makes a large difference, this really only applies to extremely hard metals that become very brittle. Tempering them reduces strength, but also increases ductility. You want both as high as you can get, but there is a certain point at which the metal is the best for a gearbox. The design of it is more important once you get to the point of using similar metals (i.e. low carbon steels that are used in most gearboxes)... such as reinforcements at the highest stress areas, and rounding of the corners around the cylinder. Of course, higher quality metals are a plus, but for low temps, the requirements are different than at normal temperatures. You don't want the absolute strongest metal you can find, you want one that retains strength and ductility at low temperatures, such as very soft steels.