pic: Crab Module

[JesseK]

First of all, Welcome to ChiefDelphi!

I have a sample side plate from 118's crab module talk in 2009. The teardrop design is the strength of the side plate; to be honest most of the material that is not on the edge of the teardrop is excessive weight. The hole at the bottom of 118's plate is ~0.2", and all pocketing on the teardrop leaves a width of only 3/16" wide behind. The plate is 1/4" thick. I estimate the fillets at either a 1/8" or 3/16" radius as well.

The poster's particular teardrop design looks exactly like 118's except it looks like there's 1/4" worth of material left after pocketing instead of 3/16" (i.e. stronger if anything). The fillets on this design look somewhat small, which is the only thing I would suggest changing for a prototype.

I doubt the module will fail due to racking for the simple fact that the bottom axle is a dead axle. The axle also serves as a strut to complete the "box" support that keeps the module from racking (laterally failing, leaning, flexing, however you want to put it). The talk linked above gives more details.

Originally Posted by Chris is me

... While I don't suggest changing the design for the sake of being different, why not just buy modules from them?

Perhaps they want the experience in getting feedback on a proven design. Or, better yet, perhaps they'd like to try their hand at innovating the design? It's far from perfect since it's still quite expensive to produce. Perhaps I'll post an idea I've had for a few months on how to further progress the coaxial crab module design.