Originally Posted by
tudorowen1
Some people seemed to be confused with what posted..I suggested a rear derailleur because Paulash has bought a BWR hub but he cannot fit the Brompton derailleur because he does not have the required braze on.
As it turns out, I found some small (3.5mm bore) hex nuts in my workshop. The fit into the wingplate is perfect. So am considering using two of these nuts and a long 3.5mm bolt to make my own HXB.
Can any of you perhaps tell me the distance in mm from the end of the frame tube to the centre of the HXB boss?
Also, I see from the diagrams that the HXB is a little off-centre -- is that correct? If so, a measurement across the tube to the centre of the HXB would also be extremely useful.
I would drill a 3.5mm hole right through the tube for the long bolt and secure it to the opposite side of the tube with an appropriate nut, washer and Loctite. 3.5mm is a small hole but could it weaken the frame in any way?
Originally Posted by
tudorowen1
Rec suggests a Shimano tourney rear derailleur..good choice because it has a short cage so some decent ground clearance..You need a Shimano Tourney that bolts onto the rear axle just like the old chain tensioner does..not the type of derailleur that bolts on to a gear hangar..There is no reason why this should not work that I can think of..You will also need an old friction shifter to operate it..either one for an old front derailleur would do or rear derailleur..Front changer would be better because it will be on the left side of the handlebars..
You are more likely to find everything in a bike shop that sells seconhand bikes or low end cheap bikes..
This is my back-up plan if the homemade HXB doesn't work out.
Thanks again to you all for your help. I'll keep you posted.
UPDATE: Brompton's Zendesk recommends
against drilling into the tube. So, a Shimano derailleur is the next move.