tinkers construct bolts have an alternative recipe that can be enabled in the config that allows bolts to be made with an arrowhead and a tool rod in a crafting grid which allows a lot more customization than the original method
it allows for more customization as you can use different tool rods rather than relying on solely iron tool rods, therefore allowing things like mana-infused enderium tipped bolts which has more durability than a traditional iron bolt with an enderium tip :v