Weapon Workbenches and every other crafting station can be found in numerous spots around the Starfield, but finding one when you need it can be a tricky task. The good news is that one spot always has the stations you need, and I have the exact location for you in this guide.
Where to Find a Weapon Workbench in Starfield
You can find a Weapon Workbench in the basement of The Lodge building in New Atlantis. The Lodge is the main hub for the Constellation faction in the main story and is based out of the planet called Jemison. Fast travel directly to The Lodge is possible, and it makes accessing this bench in Starfield incredibly easy.

To reach The Lodge basement, you need to join their crew and receive the key to open the basement door. The entrance to the basement is on the right-hand side of the building when you first walk in. An easy way to find the entrance is to look below the only staircase in The Lodge. It leads directly to the full workshop.
Related: How to Smuggle Contraband in Starfield
The basement in the Lodge has nearly every crafting station you could want in Starfield, including the Weapon Workbench. Considering you also get a small room to store items in this building, it makes it a fantastic hub until you get more upgrades later in the game.
Once you have enough resources or Credits, you can add a Weapon Workbench to your personal ship. This will require you to add upgrades like a Workshop or a Science Lab, but it can save you tons of time after installing them. Until then, head to The Lodge or keep searching around outposts for when you need some upgrades.
To get ahead of the crafting curve, learn where you can get Lithium in Starfield.