I discovered that if one adds a dagger to a repeating crossbow the resulting bladed, repeatingcrossbow is treated as if it is entirely made from the dagger material. I discovered this oddity while producing high grade crossbows for my military. I usually use bone crossbows, because bone is usually an easily available resource and not heavy. By mass-producing I quickly train a dedicated bowmaker to become legendary (the resulting masses of low quality crossbows can be traded). The same is being done with rock mechanisms. Once you have high grade, bone crossbows and rock mechanisms one can merge the two into repeating, bone crossbows, which by themselves are not worth more than the simple crossbows. Then merge you merge the masterful bone, repeating crossbows with metal daggers. While I could only add fairly low quality daggers (my weapon smith wasn’t trained yet), the result was usually an at least exceptional FULL metal, bladed, repeatingcrossbow! The whole crossbow morphed into the material of the dagger while keeping a overall high quality of at least exceptional. This way you produce a high value metal weapon relatively early even if you lack a high-level weapon smith. Also production of high quality, welded mithril, bladed repeatingcrossbows by the dozens is possible to give to your military without using to up too many precious resources.
PS: A masterwork, welded mithril, bladed, repeatingcrossbow is worth 9000 urists. Compared to a high quality battleaxe of the same material, this may be less but one only needs a low quality dagger which only consumes 1 bar compared to the 3 bars of the battleaxe.