Thank you Chris and Jim. Very helpful input that I will pay close attention to with the B72. Bacon hammers for this piano.For hammer material, cherry, walnut and many other native species are obviously stable and lighter than maple. Also easy to obtain. But they have to be resilient against splitting when those staples are propelled in from opposite sides. Change the staple to a single t-staple like an abel hammer, pre-drill, and then wood selection is opened up - perhaps? Pounding those staples into such a narrow area on a small piece of wood is asking a lot of any wood species, IMHO.If I were to make a hammer I think I'd start with a pressed T-staple inserted through a pre-drilled pilot hole. However, I'd want it tight enough to not rattle, ever. I've heard hammer rattling that I suspect was this, once other things were ruled out to best of ability. IMHO...Poplar comes to mind for a lighter hammer, yes / no? Of course, what's wrong with mahogany? Hammers use up so little wood, especially for a boutique specialty application. Sapele (from Africa) was being offered at Ronsen, but its not the same as softer mahoganies one sees being used for acoustic guitar necks. Sapele feels heavier and can have a wavy interlocking grand that doesn't help its workability sometimes. I believe the guitar neck Mahogany is what one would wish for light hammers. Very stable, very homogenous in grain and texture. Strong and light. That would be Genuine Mahogany, or Honduran Mahogany, grown on plantations. Also available from sinker logs. Forests are plagued and threatened by gluttonous excessive demand for mahogany by richer countries - that started about 250 years ago...Also: African Mahogany, a viable substitute, same family as Sapele but much closer in properties to genuine mahogany.The crispness and slightly brittle nature of Mahogany, particularly as the end-grain orients for checking, I think is quite unique when combined with its light weight. But Sapele possesses a harsh, brittle and microcrystalline mineral quality that seems to aid checking performance. That same quality dulls blades :) Soft Maple on the other hand, I don't think holds up as well.You could 3D print hammer cores with a decent selection of material qualities, made to exact shape and weight, with a diamond texture pattern for back-check contact.... boy, I'm starting to repeat myself here. Meh.. I'm obsessed with hammers. What's new.