File classification by cut density A hand file having about 50–60 teeth per 25 mm length is termed what class of file?

Introduction / Context:
Files are categorized by coarseness (cut) such as rough, bastard, second cut, smooth, and dead smooth. Proper selection ensures efficient stock removal, good surface finish, and minimized clogging or chatter during hand finishing.

Given Data / Assumptions:

• Tooth density is specified as 50–60 teeth per 25 mm (approximately per inch).
• Standard single-cut or double-cut file categories.
• General-purpose metal filing, not woodworking rasps.

Concept / Approach:
Coarser files (bastard, second cut) have fewer teeth per unit length and remove material faster but with rougher finish. Finer files (smooth, dead smooth) have higher tooth density and provide finer finishes. Typical ranges place bastard around mid-20s to low-30s teeth per 25 mm, second cut higher, smooth around 40–55, and dead smooth around 55–60+ depending on standards and manufacturer.

Step-by-Step Solution:
Interpret 50–60 teeth per 25 mm as a fine cut.Match to classification charts: this aligns with smooth to dead-smooth range.Select the nearest standard designation: “Smooth file”.

Verification / Alternative check:
Toolmaker catalogs and trade tables list smooth files roughly 40–55 TPI and dead-smooth around 55–60+ TPI; thus 50–60 sits in the smooth region leading into dead-smooth depending on brand.

Why Other Options Are Wrong:
Bastard and second-cut are coarser with fewer teeth; dead-smooth may start near 55–60+ but 50–60 typically falls under smooth; rasp files have very coarse individually raised teeth for wood.

Common Pitfalls:
Ignoring material type and clogging tendencies; using too fine a file for heavy stock removal reduces productivity.

Final Answer:
Smooth file