Um, build hammer while near your black forge I would imagine, assuming you do, in fact, have all the bits. Flamemetal ingots and a bloodstone gem arent a high bar to clear, although you do have to take a fort or two. (Also a couple of morgren sinews, which you should have by the time you've got a bloodstone). If you do, actually have everything then best I can suggest is getting all the bits in your inventory, go stand by your black forge and pull out your hammer, see if that helps. If it doesnt then scrap the forge and rebuild it in case the forge itself is bugged somehow.

The option to build any item with a hammer should appear the very moment you get all the required items. This is regardless of how many of those items you actually have. Also regardless you are actually in a place where you can actually place that new item. It will appear in color red because you cannot still build it... but it should appear.
If it doesn't then check again the required materials because you're missing something.

have the same problem

try making Mechanical spring first. It's made on Artisan table

Originally posted by Florelit:

try making Mechanical spring first. It's made on Artisan table

Yes, you need to have all components known for a recipe option to appear.

i have the same problem for the metal cutter i have the mats:
Black marble x5
Flametal x5
Ashwood x5
Charred bone x4
but it does not show up. I've tried to deconstruct the black forge and build it somewhere else but notting seems to help. any solutions for this yet?

sadly nothing appears to work

The menu icon for the metal cutter is a bit hard to see, and even if you see it - it looks like it is disabled at first glance.
Check the icons that come right after the black forge one by one. One should be the metal cutter.