Pair of Vintage Armstrong No. 412 Heavy-Duty 12" Deep-Throat C-Clamps – Made in USA

Up for sale is a matched pair of vintage Armstrong No. 412 heavy-duty industrial C-clamps. These are legendary, industrial-grade tools manufactured in Chicago, Illinois, USA. Built from high-quality drop-forged carbon steel, these frames are designed to withstand severe clamping pressure without flexing or springing—making them highly sought after by professional welders, fabricators, and machinists.

Because they feature the premium deep-throat pattern, they provide excellent extra reach over the edge of your workpiece compared to standard-depth utility clamps.

Specifications (Per Clamp):

• Brand: Armstrong Brothers Tool Co.

• Model: No. 412 (Deep Throat Pattern)

• Max Opening Capacity: 12 inches

• Min Opening Capacity: 4 inches

• Throat Depth: 6-3/8 inches (measured from the center of the screw to the back of the inner frame)

• Screw Size: 7/8-6 ACME Thread

• Material: Heavy-duty Drop-Forged Steel

• Origin: Made in Chicago, IL, USA

• Combined Weight: Just over 25 lbs for the pair

Condition:

Both clamps are in solid, fully functional vintage condition. They show typical cosmetic wear, surface patina, and minor rust from honest workshop use, but the frames are perfectly straight and free of cracks, structural bends, or weld repairs. The heavy-duty ACME-threaded screws turn cleanly through their ranges. The pads and sliding handles are intact and ready to work. Please review the photos carefully to verify the exact cosmetic condition.

Shipping & Handling:

These are exceptionally heavy, solid steel tools weighing just over 25 pounds together. They will be packed securely with plenty of padding to ensure safe delivery.