Tarrakk Blackhand:
After suffering defeat at the hands of my friends Stegadon, I built my final BFSP piece - a Hobgoblin Bolt Thrower. 
Here’s the Hobgoblin Bolt Thrower that I made using parts from the Dwarf Grudge Pony Mining Cart, a Tomb Kings Spear, some Evergreen Sheet Styrene and a piece of craft string.
The Battle For Skull Pass Night Goblin Heroes were converted to Hobgoblins by filing down their pointed hats and changing the items that were in their hands into a Bolt and a hammer/crescent wrench combination. The little pot of mushrooms and the Squig were left alone with the exception of removing the mushrooms from the pot using a drill. 
Note how I tied the craft string - it’s a clove hitch knot. I got the idea of this general layout from some of the posts on this fourm board and a book on Midievel Battle Tactics.
My second Hobgoblin Bolt Thrower’s table is a little bit lower than this one. I might switch the Hobgoblin crew around between the two Bolt throwers because of the height of the goblins to the table.
Enjoy!