When joining abutting parts, if the thinnest material is 2.0 mm thick, what is the maximum allowable offset?

• A. 0.50 mm
• B. 0.10 mm
• C. 0.20 mm
• D. 0.02 mm

Answer: (C)

The main idea here is that fit-up tolerance for abutting parts is a small fraction of the thinnest material to ensure the weld sits properly and the joint fuses evenly. A common standard is that the maximum offset allowed between abutting faces is about 0.1 times the thickness of the thinnest plate. With a thinnest piece of 2.0 mm, that gives 0.1 × 2.0 mm = 0.20 mm. So the largest misalignment you could acceptable is 0.20 mm, which keeps the weld centered and avoids excessive edge mismatch on one side.

If the offset were larger, one side of the weld could be weaker or undercut, and the joint could distort more as it cools. If you look at the other options, they’re either far larger than the typical 0.1× thickness allowance or unrealistically tight for production tolerances, while 0.20 mm matches the standard proportion for a 2.0 mm plate.