Keith,
How about 'it varies', according to what you want? I have been doing this for some time, and am very pleased with the results on traditional 4W wagons.
For 9' or 10' wheelbase wagons, placing the coupler so that the 'bumper bar' is in the same plane as the buffer heads means that the wagons buffer up when pushed, yet are still fully protected against buffer locking, still have enough slack to uncouple on straight track, and pull out to scale distance for a loose coupled train when pulled. Set up like this they are 'on the limit' on 600mm radius, and will not couple up or uncouple, because the coupler is tight.
For your slightly tighter radii you may need to set the bumper bar slightly forward of the plane of the buffer heads. Similar adjustments are required for longer fixed wheelbase and bogie vehicles, I tackle these on a case by case basis, since they are a minority in my operation.
A problem you may well encounter. The distance from buffer face to axle can be too short on some wagon designs to accomodate the NEM pocket. Having started shortening the coupling distance on my Bachmann 16T minerals by cropping approximately 2mm off the front of the pocket, and shortening the push in 'legs' on the coupler to match; this is what I also do on kit built wagons where space is tight. A second benefit of doing it this way is that small adjustments can be made if the coupler finishes too far inboard, by pulling it out to the required position, then securing with cyano adhesive.
How about 'it varies', according to what you want? I have been doing this for some time, and am very pleased with the results on traditional 4W wagons.
For 9' or 10' wheelbase wagons, placing the coupler so that the 'bumper bar' is in the same plane as the buffer heads means that the wagons buffer up when pushed, yet are still fully protected against buffer locking, still have enough slack to uncouple on straight track, and pull out to scale distance for a loose coupled train when pulled. Set up like this they are 'on the limit' on 600mm radius, and will not couple up or uncouple, because the coupler is tight.
For your slightly tighter radii you may need to set the bumper bar slightly forward of the plane of the buffer heads. Similar adjustments are required for longer fixed wheelbase and bogie vehicles, I tackle these on a case by case basis, since they are a minority in my operation.
A problem you may well encounter. The distance from buffer face to axle can be too short on some wagon designs to accomodate the NEM pocket. Having started shortening the coupling distance on my Bachmann 16T minerals by cropping approximately 2mm off the front of the pocket, and shortening the push in 'legs' on the coupler to match; this is what I also do on kit built wagons where space is tight. A second benefit of doing it this way is that small adjustments can be made if the coupler finishes too far inboard, by pulling it out to the required position, then securing with cyano adhesive.
