By following the steps below, you can create custom toolbelt profiles, which you can use to switch swiftly between sets of tools.
By using the command "settoolbelt" you can set any toolbelt slot to any item. You need to know the unique item id for this (which is a large number).
In the following section "~/wurm" is used to denote the directory where your wurm data is stored. Under Windows, this is probably "C:\users\<username>\wurm", under Linux, it is mostly "/home/<username>/wurm".
1) Set your toolbelt up in the way you want it in Wurm. Note which tool is in which slot (numbered from the left, starting with 1). Quit the game.
2) Open the file "~/wurm/players/<wurm playername>/playerdata.txt". This contains a number of lines that look like
Remember the order from step 1, write down which <number> corresponds to which tool.
3) Create a new file "~/wurm/configs/default/blacksmithing.txt" (or any other name you want in that directory). Insert as many lines for setting the toolbelt (and custom keybindings and whatever else you want) as follows:
settoolbelt <number> 1 // <comment describing the tool> settoolbelt 266029938770434 2 // mallet settoolbelt 812487435879682 3 // file ...
4) Restart Wurm. Open the console (by default bound to F1). Type
bind Alt+1 "exec blacksmithing.txt"
You can use any other keybinding you want, and use any other file.
Also see http://www.youtube.com/watch?v=__T9ExMnjAI and http://forum.wurmonline.com/index.php?/topic/57806-the-settoolbelt-console-command/ for more information.