Some Knex connector ideas i came up with to make better knex cars. The large ball joints can be pressed into the parts labeled "A-arm bracket" to use for making A-arms for a car suspension. The "bearing holder 8 connector" is designed to have a 5/8 OD, 1/4 ID bearing pressed in. You may find that the parts print too tight or too loose- try scaling the part + or - 5%. I've found that ABS has better flexibility and tends to work better and not break as much as PLA.