The Staton gearbox has three gearshafts inside. The first connects to the engine's clutchdrum. That shaft's gear meshes with a 5:1 intermediate shaft which then meshes with the output shaft for an 18.75:1 gear reduction.
There is only one output shaft on the older-style gearbox, either on the inside or outside of the box. Then the updated gearboxes evolved with output shafts on the left side, right side, both sides AND where the 5:1 intermediate shaft locates.
Instead of buying a newer gearbox with the 5:1 output shaft, it would seem to be a simple matter to bore a 5/8" hole thru the gearbox left-sidecover. Then you just buy Staton's 5:1 intermediate shaft with 3/4" output shaft for the sprocket.
For that matter, you could bore the opposite side cover at the main output shaft, buy Staton's later-model output shafts and convert from one-side output to dual sprockets. Orrr, converting the outside drive gearbox to inside drive. In other words, upgrading and retrofitting to Staton's newer output shafts.
I had mulled over buying another gearbox with inside drive, especially while dreaming about a NuVinci conversion. This option is WAYYY cheaper than a new box, as the Staton's output shafts are only $29.95. His gearboxes sell for $250-$280.
On paper, it seems do-able. I want to tap off my Staton gearbox for 5:1 gear reduction to run my 100-watt miniature alternator. The dynamo puts out its power at 1,000rpm, so I need to gear it down from my engine's 8,000 rpm spins.
So the BIGGG question is.....has anyone modified their Staton gearbox for 5:1 gear reduction?