It's Called Borrowing

For this questline you need to be on your Dark Iron Dwarf (lvl 50+) and currently it has to be the DID that did Heritage of the Dark Iron.
Use your Mole Machine to get there, it's in your general spell tab. Select Eastern Kingdoms > Shadowforge City.

1. 
   
2. The Anvil-Thane's Designs - turn around and walk forward, upstairs, follow the way on the right side (don't jump down) and enter the Grim Guzzler
3. 
   
4. Brawl or Brew - click her dialogue and select "brawl". Fight against [npc=26125]
5. 
   
6. It's Called Borrowing - go down and kill [npc=176995] for [item=184916]. Go back to the ramp where you came from and collect 5 [item=184915], they lie around in the big marked area near the [npc=144132]s. Follow the way until you reach Kasea Angerforge and ask her for the [item=184917]. Turn around and go back a bit to turn in the quest
7. 
   
8. Weapons o' the Dark Iron - talk to [npc=144154] and click the darkforged ingot
   Turn in and get [item=184922].
9. 
   
10. Delivery for Kasea - follow the way back
11. 
    
12. Good Fiery Boy - click [npc=185352] next to you, throw it on the ground and click [npc=185305] to pet him. Collect 4 [item=190606] from the boxes and feed him. After that, click the extra action button [spell=367727].
    Turn in and get [item=191123].
13. 
    

Questline took about 15 minutes with level 52 and ilvl 85.

Darkforged Ingot can be found in the upper ring of Shadowforge City and in the Hall of Crafting.

Boiling Flamecore can be found in the Grim Guzzler. You need to kill Boiling Flamebringer for it.

Flamepoint Engraver can be found by asking Kasea Angerforge for it. She's Southwest from the Black Anvil.