By cracky

My grandfather in northern Missouri uses a lot of colorful phrases. One of the funniest is "by cracky", used in place of "by golly". For example, "It's a hot one today, by cracky!"

Does anyone know the origin of this phrase?

Jumpin' Jehosophat, you have sure found one funny-sounding phrase. In his day your grandfather was just one of many who used that euphemism, "by cracky," without thinking twice, as a natural way of being emphatic without directly naming Christ (which would be blasphemy).
SS