Old Britts – Drifts Used in Building a Norton Commando
Download the complete PDF version using the green download button at the top right of this page for an Old Britts technical article listing the workshop drifts used when building a Norton Commando. Written by Fred Eaton, this reference explains the advantage of purpose-made stepped drifts over ordinary sockets when removing or installing bearings, bushings, seals and related components, particularly where accurate centering and controlled pressure are important.
The article begins with a labeled diagram showing the first-step and second-step dimensions used throughout the drift tables. It explains that, when installing a bearing, the first step should locate in the inner race while the second step presses only on the outer race, avoiding load on the bearing internals. The dimensions are then organized by motorcycle area so readers can identify the drift required for a particular workshop job.
The tables cover wheel bearings, brake drum bushings, steering head bearings, gearbox bearings and seals, layshaft and sleeve gear bushings, camshaft bushings, MK3 primary case bushings and Amal carburettor spray tube work. Each entry gives the drift number, step diameters, step lengths and the intended use, making this a useful shop reference for anyone machining their own drifts or comparing suitable substitute tools.
Contents Include
- Old Britts drift dimension reference for Commando workshop work
- First-step and second-step drift design explanation
- Why stepped drifts can be better than ordinary sockets
- Wheel bearing and brake drum bushing drift dimensions
- Steering head bearing installation drift
- Gearbox bearing, oil seal and bushing drift sizes
- Layshaft, sleeve gear and mainshaft applications
- Camshaft bushing removal and installation drift
- MK3 outer primary shift shaft bushing drift
- Amal carburettor spray tube removal and installation drift
