What split on you? The closest that I have come to making the wood bass that you have are pickup rings that I made out of maple. Knowing what I know now, I would probably make them out of a softer wood. Maple was hard to sand to remove material and also had a high propensity to split...much like at your eyelet. I mention this because of the mention of Ironwood... We don't have that here in Florida so I had to look it up. Wow! that stuff is hard...like somewhere between Brazilian and Honduran rosewood hard. It looks like it might make a harder version of a maple fingerboard...A light fingerboard over a mahogany neck would look very cool...but I digress... Is there an advantage to using a very hard wood for the base of the pickup rather than an easier to work wood?

In any case...this is looking more and more like an Aussie Boutique pickup ;-)