F2P Crafting guide
For 1-8 make leather gloves (to 7) and then boots to 8. This about 55-65 pieces of leather and will take a few minutes. (longer if you tan your own hides.)
OPTIONAL - Do those to level 5. (29 gloves).
Level 5 - Gold rings until 8, (27-30 rings) Level 8 - Gold amulets until either; 16, 20, 27, 34, 43, 99. (or whichever your target level is.)
At level 16 you can start making unstrung symbols (50 experience, 60-90 gp loss - About 1.5 gp/xp loss) and 45-55k xp/hour and 60-100k gp loss/hour
Level 20 you can make sapphire rings, or cut sapphires (or both at the same time https://www.youtube.com/watch?v=N06TVkiFDLw) Sapphire rings are currently +145 gp each to make, at 40 experience each ( +3.625 gp/xp) and are about 26k xp/hour and 90-100k profit/hour.
Cutting sapphires is a loss of 419 gp per sapphire and 50 experience each, (-8.38gp/xp) 200-235k xp/hour cutting these. Guides on cutting gems below;
https://www.youtube.com/watch?v=wf0Rb3GUnBE
https://www.youtube.com/watch?v=X7noApVNh4c
Level 27 you can cut emeralds, and make emerald rings emerald rings are +112 gp to make each, and 55 experience each. (2.036xp/gp) 65-75k profit/hour and 30-40k xp/hour. Cutting emeralds is -525 gp to cut one, for 67.5 experience, (303-317k xp/hour and 2,362,500-2,467,500 loss/hour). -7.78gp/xp
Cutting rubies at level 34 is an expensive method. (-16.64gp/xp) but is 365-400k xp/hour which is comes at a cost of; 6-6.65million gp loss/hour.
The last decent option for F2P Crafting is to cut diamonds; a huge 22.31 gp/xp loss. But an insane 480-505k xp/hour, (10.7-11.2 MILLION GP LOSS/HOUR). If you have a huge cash pile you can get 99 Crafting from level 43 in 2-4 days cutting diamonds. But at the cost of 280-300m.
For making jewellery always make at Al Kharid furnace, for cutting gems cut at Falador West, or Varrock East (video links).