When flan's and chisel are installed the iron ingot in recipes turns into some untextured block that you can not identify, so crafting things is impossible.

Link to chisel: http://www.minecraftforum.net/forums/mapping-and-modding/minecraft-mods/1294901-chisel

yeah the weapons recipes are fixed now. The simple parts are still broken.

I'll just add to this, this has been a problem since 1.6 (as far as I can tell). I had this previously, I think it's because Chisel adds its own iron block (among other copies of vanilla blocks) and then has all the retextured ones under the same ID with metadata, seemed like in the recipe txt files when it referred to 'iron' it would grab these blocks, which are also uncraftable. To fix this I had to change any instance of 'iron' to 'ingotIron'.

It used to grab Chisel's glass and random wood from Forestry as well back in 1.6, but it doesn't seem to do so now.

Should be fixed by ad3525d