Oil grooves for bushings?

[keith hodgsonParticipant @keithhodgson40059]

Hi all,

Tried a search, but couldn’t see that this topic had come up before.

I’m restoring an early 30s 2 stroke motorcycle engine which still has phosphor bronze bushes for the main bearings. It also has a Villiers flywheel magneto clamped to an extension of the rhs main bush, meaning that for a 3/4″ dia shaft, the bush is just shy of 2″ long. I’ve made the lhs bush (shorter, in 2 pieces), and am now about to start on the rhs, but this one has figure of eight oil grooves for lubrication.

Can’t think of a way to machine these, my leadscrew is 4 tpi, so pitch of grooves is way too coarse. Been on internet/youtube, and seen a home made lathe accessory that involves bevel gears driven from chuck, priced up same, about 300 quid from HPC – for one bush this seems a bit OTT.

Has anyone made one of these/could offer a service for my bush (willing to pay), or has another solution?

Maybe a set of 2:1 bevel gears, largest 3-4″ second hand (long shot) for 50 quid?

[Author]

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