Although fletching seems like one of the easiest skills in the game, I want to provide you with a guide with level requirements and what all you can actually do.
You can buy a knife from Bob in the home bank.
To start with the basics, here are the different shortbows and longbows you can fletch. Fletching bows is the fastest way to gain xp.
1 Arrow shaft
5 Shortbow
10 Longbow
20 Oak Shortbow
20 Oak Longbow
35 Willow Shortbow
35 Willow Longbow
50 Maple Shortbow
50 Maple Longbow
70 Yew Shortbow
70 Yew Longbow
80 Magic Shortbow
80 Magic Longbow
Here are the different arrows you can create. Fletching arrows is not normally recommended as they are easily acquired in the range shop, don't hold a lot of value, and take a lot of time to gather the resources. You will need to smith the arrowtips, or receive them as a drop from monsters. You will need to chop regular logs to create arrow shafts, and you will also need to collect feathers.
1 Bronze arrow
15 Iron arrow
30 Steel arrow
45 Mithril arrow
60 Adamant arrow
75 Rune arrow
Here are the different bolts you can create. Fletching bolts is definitely the biggest money maker here as these enchanted bolts are not sold in the range shop. Fletching bolts is not the fastest training method as you gain crafting xp and fletching xp.
**Bolts and uncut sapphire, emerald, ruby, diamond, and dragonstones are available in the shop. Uncut onyx are available in Entrana (High level requirements), or are dropped from various monsters*
56 Sapphire (e) (No crafting requirement) (Mithril bolts)
58 Emerald (e) (27 crafting required to cut the tips) (Mithril bolts)
63 Ruby (e) (34 crafting required to cut the tips) (Addy bolts)
65 Diamond (e) (43 crafting required to cut the tips) (Addy bolts)
71 Dragon (e) (55 crafting required to cut the tips) (Rune bolts)
73 Onyx (e) (90 crafting required to cut the tips) (Rune bolts)
The fletching cape increases your speed. The master fletching cape allows you to create extra bolts!
