We establish L bounds for the Bourgain-Stein spherical maximal operator in the setting of compactly supported Borel measures μ, ν satisfying natural local size assumptions μ(B(x, r)) ≤ Crμ , ν(B(x, r)) ≤ Crν . Taking the supremum over all t > 0 is not in general possible for reasons that are fundamental to the fractal setting, but we are able to obtain single scale (t ∈ [1, 2]) results. The ran...