The Cuckoo Clock by Mary Stolz, 1987.

Erich was a foundling, taken in by the Goddhart family as a baby after he was found on their doorstep. Frau Goddhart has a reputation for kindness, but sadly, that reputation is really all she has. She is outwardly kind, participating in local charities, only to enhance her reputation. At home, she is selfish and cruel, ruling the house with an iron fist and having tantrums when things don’t go her way. She sees Erich as an unwanted responsibility, only grudgingly raising him along with her own children because if she refused, it would ruin her reputation. Her husband is kind to Erich, but Frau Goddhart treats him more like a servant.

Erich only comes to know real love when he becomes Ula’s assistant. Ula is the town clockmaker, a master in his craft. Ula teaches Erich his craft and how to play the violin.

When Ula dies, leaving Erich his carving tools and his violin, the selfish Frau Goddhart tries to take them away, thinking that such things are too good for a mere foundling, a charity case. Before she can get these precious things, Erich runs away to seek his fortune elsewhere, but he leaves behind something that convinces the town that, although he may be the ungrateful wretch that Frau Goddhart says that he is, he has a talent that will lead him on to greater things.

One of the fascinating things about this book is the pictures, which are charming pencil drawings in a realistic style.  There is also a note in the back about the unusual typeface of the book.