World War II Era Willie’s jeep speedometer

The jeep that this speedometer belonged in was towed at 70mph - faster than the speedo was designed to measure - which resulted in severe damage which rendered it non-functional. The major problem was the central spindle onto which the aluminium drag cup and regulating hair spring are fixed; the spindle had snapped clean in two. Spare parts for this model of speedometer are no longer available, so a replacement arbor had to be turned to very precise tolerances in order to ensure the drag cup and hair spring could be fitted with a friction fit.

Additionally, the brass bearing in which the spindle is designed to run had been completely torn out. Replacing this was not a simple bushing operation since the bearing is set deep in the magnet frame - a sub-assembly that is riveted together. In order to avoid having to file off and replace the rivets, an unusual rebushing procedure had to be designed. First, the hole was plugged with a brass spigot, riveted in place by rolling over the remaining material from the original bearing wall using a custom burnisher. The entire sub-assembly was then mounted in the lathe in a bespoke-built collet in order to allow a new pivot hole to be centrally drilled. This was done using a D-bit, handmade to the correct hole size.

Finally, the zero-set flag on the drag cup had also been snapped off. Fortunately the circumferal position of this is not crucial, as the hand is a push-fit which can be positioned to suit, so a new flag was made at a different position. These flags were originally pressed out of the aluminium during manufacture; in order to replicate this appearance and provide the new flag with equal strength, I pierced a tab out of the aluminium and bent it up into position.