Andy,
The need for hubs has come up just recently, but not frequently enough in the past that it has been viable to make a batch. Usually it is up to the various owners to make a few extra when replicating parts they need.
I do need to point out the drawings mentioned were done for a 1936 Aero model, so the axles will need modifying in lengths to suit the DT frame. But all the big twins from 1926ish, and the big and small twins from 1930ish through 1938 used the same hub. Except- the rear DT hub when fitting a sprocket only (no-brake drum), the hub was slightly wider to maintain the chainline. If you are doing up a cinder track model and not for use on the road, I can measure the difference between the DT and the standard road hub. But I gather not, since you are looking to fit a Norton four-speed gearbox. Also in the mid-thirties, Douglas offered a drop-out rear wheel option on certain models like the Blue Cheif, that had a different hub.
BAS and Graeme also recently requested hub drawings for road going DT models too, so maybe all three of you can arrange something. Send me a Private Message with an email address and I'll get you the drawings as an attachment.
-Doug
