home made k frame
Engineering. Engineer. Math. Maff is hard.
Also realize this:
Just because someone manufactured one and markets the thing does not mean it is strong enough. Or that it has even been engineered mostly "at all." It also does not mean that a given product can put up with street use, jouncing, impact, cornering / side/ front/ rear braking, the bouncing of the tremendous force of an engine mass against it.