Let A be a group of order 2n
which acts as a fixed-point-free group of operators on the finite solvable group G. If
no additional assumptions are made concerning G, then “reasonable” upper bounds
on the nilpotent length, l(G), of G have been obtained only when A is cyclic
[Gross] or elementary abelian [Shult]. As a small step in extending the class of
2-groups A for which such bounds exist, it is shown in the present paper that if
|A| = 8, then l(G) ≦ 3 if A is elementary abelian or quaternion and l(G) ≦ 4
otherwise.