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Difficulty: MediumChisels, Files, and Planes

A mechanic needs to manually cut and finish a narrow rectangular keyway slot into a mild steel plate using bench and hand tools. What is the correct sequence of steps to complete this operation accurately and safely?

  1. 1Apply layout dye, scribe the slot boundary lines, and mark drilling locations along the centerline using a center punch.
  2. 2Drill a row of overlapping or closely spaced relief holes along the centerline to remove the bulk of the internal metal.
  3. 3Drive a narrow cape chisel between the holes with a ball-peen hammer to shear the remaining metal webs and establish rough slot depth.
  4. 4File the sidewalls and bottom of the slot with a square or pillar hand file to achieve final dimensions and a smooth finish.

Answer

The correct operational sequence begins with laying out the slot boundaries and center-punching, followed by drilling relief holes along the centerline, shearing out the remaining metal webs using a cape chisel, and finishing the slot sidewalls and bottom to final size with a hand file.
The standard mechanical process for manually cutting an internal slot or keyway always progresses from layout and hole preparation, to rough bulk removal with a specialized grooving tool (cape chisel), and ends with fine dimensional truing using a hand file.

Step-by-Step Solution

1
Lay out the slot dimensions on the workpiece surface with a scriber and mark drill centers with a center punch.
Defines clear boundary limits and creates positive indentation seats for drill bit centering.
Machining or cutting without precise layout leads to dimensional errors and tool wander.
2
Drill a series of relief holes along the centerline of the marked keyway slot.
Evacuates the majority of the solid steel core within the slot perimeter.
Relief drilling reduces the volume of solid metal that must be manually sheared by hand striking tools.
3
Use a cape chisel struck firmly by a ball-peen hammer to knock out the remaining metal bridges between the drilled holes.
Forms the rough channel to approximately full depth.
Cape chisels feature a narrow cutting face with slight side relief designed specifically for cutting keyways and grooves.
4
Dress the bottom and true the vertical walls using a square or flat hand file with safe edges as needed.
Produces a smooth, straight, parallel-sided keyway slot meeting required tolerances.
Files provide controlled fine material removal to eliminate rough chisel marks and establish final fit.

Key Concept

Standard shop procedure for manual keyway cutting: Layout → Relief Drilling → Cape Chisel Channeling → File Finishing
Estimated Time:1m 0s
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Topics

Chisels, Files, and Planes

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