True or false: The rough surface of the flat file should be in contact with the material when deburring a hole.

The correct answer is true, as the rough surface of the flat file is specifically designed to remove material effectively when deburring a hole. Deburring involves smoothing out sharp edges or irregularities resulting from machining processes, and using the rough side provides the necessary abrasive action to achieve this.

When the rough surface is in contact with the material, it allows for the removal of burrs, which are typically leftover sharp edges that can be hazardous or interfere with assembly. This process is essential for ensuring that components fit together properly and function as intended. Using the rough surface enhances the efficiency of the deburring process and helps in achieving a smoother finish more effectively than if the smooth side of the file were used.

The other options imply that there might be variability based on material or file type, which could apply in certain contexts, but the fundamental principle that the rough surface should contact the workpiece for effective deburring remains consistent across general practices.