Unfortunately, the 1890 US census was virtually destroyed in a Washington fire, with only about 1% of the census available. However, the 1880 US census shows an unmarried John Prechtel, born in 1862, listed as a blacksmith and living in Cleveland OH. Both parents listed as being from Prussia (this fits with the info provided by M. Petrov.)
So, the scenario goes as follows:
John Prechtel, 18-year-old bachelor blacksmith, decides that there may be more interesting forms of metalwork than banging out iron utensils or repairing wagon suspensions, and vows to give gunmaking a try. Sometime after 1880, but before 1900, young Mr. Prechtel arranges to apprentice with the well-known Daniel Myron Lefever of Syracuse NY (possibly through the auspices of other German immigrants?) After spending some indeterminent amount of time under Mr. Lefever's guidance, J. Prechtel is allowed to complete a firearm from "scratch" or nearly so, to demonstrate his proficiency in the craft and to become a Journeyman in Good Standing. Thereafter Prechtel, gun in hand, returns to Cleveland and sets up shop on his own.
It would be great to find some sort of Syracuse documentation for Prechtel, although I think the (mispelled) time board is pretty good evidence.
Hats off to Michael Petrov for the detective work!
[I posted this in response to a similar thread over at http://lefeverforum.informe.com that utilized MP's research as found in this thread] 
