Hand cutting tools — the usual cross-sectional shape of a general-purpose cold chisel shank used by fitters is:

Introduction / Context:
Cold chisels are chiselling and trimming tools used at room temperature on metals. The shank’s cross-section affects grip comfort, resistance to twisting, and the tool’s ability to withstand repeated hammer blows without excessive burr formation on the head. A common exam point is the standard cross-sectional geometry of the chisel shank.

Given Data / Assumptions:

• General-purpose flat cold chisel (not specialized cape/round-nose variants).
• Hand striking with a hammer; need for ergonomic grip and anti-rolling features.
• Traditional forged tool-steel construction, later heat-treated.

Concept / Approach:

The octagonal cross-section offers multiple flats for secure hand grip and reduces the likelihood of rolling compared with round or square sections. It balances material usage and strength while providing comfortable indexing for the user’s fingers. While some chisels may be produced with hexagonal sections, the most widely cited standard for fitter’s cold chisels is an octagonal shank.

Step-by-Step Solution:

Verification / Alternative check:

Commercial catalogues and workshop manuals list “octagonal shank” as the default for flat/hand chisels, with hexagonal seen on some manufacturers but less universal.

Why Other Options Are Wrong:

Rectangular and square sections are less ergonomic and more prone to edge damage; hexagonal is seen but is not the usual textbook answer for general-purpose cold chisels.

Common Pitfalls:

Assuming any polygonal cross-section is equally standard; overlooking that exam convention typically expects “octagonal”.

Final Answer:

octagonal