| Year | 1931 |
| Date | 21-May |
| Volume | 64 |
| Issue | 1,567 |
| Page | 489 |
| Category | Electrical Work |
| Part | 3 |
| Title | How Commutators are Built |
| Author | A.H.A. |
| Notes | Assembling the cut segments and fitting in the mica insulation, clamp ring for assembling large commutators, plain taper ring clamp for small commutators, tool for undercutting mica insulation |