These would be made in the USA and some made in Taiwan. Taiwan in wanting to capture the international market made high quality hardware. Both countries made fine hardware 40+ years ago and was better quality than what you can get today. My dad took these with him from his business. I worked with him in the 1970's and deposited many hundreds of pounds of fasteners from boxes to easily accessible bins and so I am intimate with these.
Serious woodworkers, grab these before others get for their little home projects. All the galvanized screws are as good as new. These better quality screws than you can purchase at Home Depot I have at around a 20-30% discount but considering the quality, it's more like a 50% discount or more.
For the bare metal items, 3/8” T-nuts and 1/4” hanger bolts, I offer a much bigger discount.
To get out of the way, one flat head screw lot I have is about 2 3/16”. I do know how these are measured. A metric size would be 55mm so maybe someone messed up somewhere. Being we are in the US, I'll speak of an equivalent and proceed for this one as:
1/4”-20 x 3” hanger bolt, 180#...................$45 (25 cents each)
3/8” T-nut, 47#.......................................$3 (a little over 6 cents each)
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Likely not from the 1970s though in my possession since before year 2002:
3/8” x 4” galvanized carriage bolt, just like new, 25#..............$12 (48 cents each)