I've got the Breon Mitchell translation. Mitchell translates 'zersingen' as singshatter which I think is a good idea. I thought Grass invented zersingen since there was no Leo entry for it but since then I've found it in Duden.
Mitchell's translation of the above is
little boy who wanted to pound on my drum had
to be kicked a few times in the shins to avoid
singshattering glass, upon which the little brat
fell over and hit his nicely combed head on a
school bench, for which I received a cuff on the
back of the head from Mama.
Here's what Grass has to say about the translation
The “shocking” parts of The Tin Drum may
have led translators and publishers in other
countries to omit or shorten passages they believed
their own readers might find disgusting or
blasphemous. And some no doubt thought that by
pruning this very long novel, written by a brazen
young author who was still unknown, they could
only improve it. I thought highly of the late Ralph
Manheim, and his translations of several of my
works into English were marvelous, but both literary
historians and translators indicated repeatedly
that his translation of The Tin Drum needed
revision. I heard the same thing about the early
translations of The Tin Drum into other languages.
Thus, in the early summer of 2005, ten translators,
including Breon Mitchell, joined me in
Gdansk with one set goal in mind: to create new
versions of my first novel in their own languages.
To prepare myself for their questions, I reread The
Tin Drum for the first time since I’d written it, hesitantly
at first, then with some pleasure, surprised
at what the young author of fifty years ago had
managed to put down on paper.
For eight days the translators from various
lands questioned the author, for eight days the author
talked with them, responded to their queries.
During breaks I would take them to this or that
spot mentioned in the rapidly shifting narrative
of the novel.
Still, I think there might be some errors in the translation. For example
Der Krug ging
immer wieder zum Wasser, was blieb ihm übrig, als zu brechen.
That was translated literally into English, but isn't this an idiom similar to the straw that brakes the camel's back?