In our shed
Alan embarks on low volume ally wheelspacer production for TDR250, like no volume (as yet). But wait...
MY MYFORD ML7 is a reassuring if sometimes accusatory presence in the corner of my workshop. This venerable lathe, now at least 50 and probably more like 60 years old, is my most extravagant workshop purchase to date.
It’s worth at least what I paid for it, so in capital terms I shouldn’t feel too bad. It’s an asset, and one that has proven its worth on many occasions. Still it mocks me, being so much more capable than I am of churning out little marvels of engineering genius. Maybe one day I’ll use it to its full potential, making working models of motorcycle engines when I’m too infirm to ride the real things [Better get on with that then – JM].
In practical terms it’s got me out of a hole more than once. I’ve become somewhat expert in the machining of spacers. When it came time to swap the cast TZR wheels my TDR used to wear for a pair of rebuilt wire-spoked ones, I obviously lacked the correct spacers for the proper rims. Or at least I thought I did, as will become clear. Cast wheels are generally narrower than wire-spoked ones as the latter require wider hubs to provide sufficient angle between hub flanges and rim centre to give the wheel lateral strength.
The TDR, as was, had extra spacers to take up the gaps between fork legs and swingarm spars, as well as crude ally spacers to move the brake calipers in over the discs. Its sister bike, Project Lightweight TDR (see page 104) came with the correct spacers positioning its wire-spoked wheels and I elected to use these rusty, pitted relics as patterns for replication in fresh aluminium.
The only bar stock I had was nearly 50 per cent larger in diameter than required but I’ve come to enjoy the gentle hypnotism of working a lathe tool back and forth. I made a pair of rear spacers first then got to work on the narrower front. A mountain of scrap aluminium curls filled the lathe’s drip tray as the work progressed. Front wheel first and the top hat I’d made showed the narrowest of gaps before the spindle was tightened up. Perfection. Turning my attentions to the rear I realised my work was redundant. A pair of stock spacers were in place, augmented by a thick ally ring to take up the considerable slack. Still, nothing goes to waste and the aluminium rear spacers I’ve made can go into Project Lightweight TDR. Meanwhile my Myford still sits sentinel, wondering when the real engineering work is going to start.
Pinch-perfect job from the son of Cornwall Nipped up to a nicety, another Cornish triumph
No shortage of swarf at the final cut