I have a machine with a slot that I want to only allow pickaxes.  When the user attempts to insert into the slot I test if the item extends ItemPickaxe.  This works with vanilla and some mod pickaxes.  However some mods (Actually Additions and Mekanism are two examples) create pickaxes that just extend ItemTool.

 

Is there a better mostly universal way to tell if an item is a pickaxe?

Thanks that was exactly what I needed.