Should look great when it’s cast in Ally.
Dave popped round with a set of patterns he’d modified to be more in keeping with the barrel. Achieving a good look aesthetically isn’t something every pattern maker would necessarily think about. Dave’s time as a model shoe maker and designer really shows.
I like what he has done as an example and now we’re cracking on with the main items. I expect it’ll take 3-4 weeks to get something we can drop onto the drawings, then filleting and artistic flare to finish off. A bit longer than the original time estimates, but hopefully ready for casting before too long.
The sleeve drive will be a duplex chain, and like all chains it needs tensioning. Like old Notions the tensioner is ally, which Bob has made a great job of carving out of some leftover billet. It’s a lovely looking thing, the sort of artifact you’d pick out at an autojumble just because.
Shame no one will see it when it’s in situ! Apart from the 44T sprocket, all of the steel components are finished. Time to give Dave a nudge about finishing those patterns!
The sleeve drive sprocket has been drilled by Bob to allow for a vernier adjustment. The 9 holes allow the sprocket to be fitted to the timing shaft in a number of different positions.
With 22 teeth not being visible by 3, three mounting holes would allow the sprocket to be fitted three ways, each time a tooth ends up in a different relative position. To refine this further, three sets of three mounting holes have been drilled.
Why? Well during final assembly the valve timing will need to be set. This will be achieved by setting the piston at the point where a valve opens, moving the sleeve into the correct position and then bolting the sprocket to the timing shaft.
Sounds so easy when you say it!