Alright first off be prepared to lose lots of money as 99 smithing costs around 100mil gold to train it this way. Also note that it doesn’t matter what you make because you get xp per bar used not item made. Now on with the guide!
Alright for this segment you are going to want to buy 193 bronze bars which should cost 57 thousand gp if bought from the G.E. and then make them into whatever you want but I suggest you keep making the item that takes the most bars that way you finish faster!
Now that you have 15 smithing you can smith iron bars into items! Now for this segment you need 439 iron bars which should cost around 156 thousand gp if bought in the G.E. and for smithing them I suggest the same method you used in the last section.
Now that you have 30 smithing you should pat yourself on the back and take a rest for a few minutes before continuing. Now that you’ve had your little break you need to buy 2,346 steel bars which should cost around 2.4 million gp if bought in the G.E. Then you are going to make them all into steel items.
Now you should really be happy because you are almost to your goal. Now for this section of the guide you should buy 12,726 mithril bars which should cost around 20 million gp if bought from the G.E.
Now you need to buy 40,336 adamantite bars for this section which costs around 125 million gp if bought from the G.E.
Now you need to buy 130,345 runite bars which costs around 2.25 billion gp if bought from the G.E.
Note: Sell all items you make from smithing and if they don’t sell on the G.E. Then sell them at the General store.
Note 2: This is not something you want to do all at one time take some breaks and come back to it.