RICK’S FIXES
The lure of lathes, the Triumph of tufnol (washers), the fun of fixing stripped threads
‘I COULDN’T OPERATE WITHOUT A LATHE, YET I MEET PEOPLE WHO HAVE ONE BUT ALMOST NEVER USE IT’
How did they make the first lathe without having a lathe to make it?’ So goes the paradox – but of course lathes weren’t invented, they evolved from the time when man realised that by spinning a slice of tree against a blade you got a better wheel than nature provided. Indeed, you could argue that lathes have been here longer than us – that’s the reason why the Earth is a sphere rather than an irregular boulder. Maybe there was no giant cutting tool to profile it, but its shape is still due to rotation. The lathe rotates a workpiece against the linear movement of a shaping edge – a potter’s wheel is thus a form of lathe. As it moves along the work, the shaping edge carves out a spiral. The pitch of this can be controlled by gearing the rotation to the linear travel; thus was the screw thread born to the benefit of mankind. That’s the thing about lathes – they can do more than you think. This month I was stuck with a rotted away valve-cap thread in an old Blackburne cylinder head. If only I had a tap a bit bigger than 1¾in x 18tpi to recut it… well, instead I found a way to use the lathe to sort the problem (see over the page) and it reminded me just how versatile this most primeval of machine tools really is. I couldn’t operate without a lathe and yet I meet a few people who have one in their shed but almost never use it, how can that be? I think it’s the Catch 22 that if you are not an engineer, you need to do ‘stuff’ to give you the confidence to do ‘stuff’. My inspiration was being told: “Just give it a try, all you can do is f*** it up!” Theory will only take you so far; you have to learn for yourself how to get the best from a lathe, because we all have different problems to solve. If you fail, don’t worry about it – you will have learned something. When you succeed it’s a great feeling and one that inspires you to move on and try something harder.