I had a go at making a hammer for my Petzl Nomic ice axes today… the guy that runs the web-site Cold Thistle makes a version of them which are far lighter and therefore affect the swing of the tool a lot less than Petzl’s own hammers. This is essentially what I based my hammer on. It’s not very pretty but will do the job for hammering in pitons without damaging the back of my axes. It was actually quite easy to make with the availability of the right tools…filling it down to make it fit properly took a fair bit of time but i’m pleased with the end result!
Sorry the photos are blurry but you can get the idea!