Searching_Ut wrote:
When I have access to a computor I'll post photos but a fifth wheels weight is carried by the fat base of the pin box riding on the flat portion of the hitch. I don't think there are any oem pin boxes with a raised round base. With the andersen hitch adapter none of the vertical load is carried by the pin. The pin weight is all carried by two of the set screws which ride directly on the pin box base plate.
The raised round base would be on the inside of the pin box. There should either be the raised round base or some sort of cross member support. I don't know how they make the 1621HD, but the standard 1621 has a cross member attached to the kingpin on the inside. The Mor-Ryde pin box I use has the rounded base, and the set screws are within the footprint of this base. It would take a major failure in order for the adapter to cause this kind of damage on the Mor-Ryde.
The kingpin itself (just the lower connecting part) cannot be connected to the plate in that small 2" diameter area. That would be an extremely weak connection.
In your other thread, you showed that the kingpin had skewed. Could this be because a weld on the interior attachment came loose, resulting in a complete loss of strength? As I said, a lot might be learned by getting a look on the inside.
