B&C could make me a sprocket but would come in at £40-50
Some interesting points raised - he says that all chain sprockets are imperial, they never went metric!
Why do I see lots of 13mm sprockets available then? May be only 0.3mm (0.012”) further between teeth but wouldn’t that start stretching the chain, when the chain is wrapped round 25 teeth that’s 7.5mm
Also, he says my 1960’s part book is wrong and the width cannot be .305, it has to be 5/16” 0.03125”