For a project in progress (for 40+ years...) I had need of a shipset of 2-56 ball links for the controls. Looking around, I could only find one package of Rocket City, but DuBros were everywhere. Not wanting to have them tighten up on me due to the plastic shrinking as is common, I dug a little further and found both plastic an aluminum Sullivan links with a captured ball. I had seen them advertised for years, but this seemed ideal, so I got some.



    Unfortunately, the "captured" part is designed in such a way that the slotted collar that captures it is forced by a spring up against the stem of the ball, making it draggy and tilting the link to about a 45 degree angle. This is no problem for RC, the servo just has to push a little harder, but for CL it's obviously unacceptable to have it drag up the controls, particularly on a smaller airplane with little line tension at times, and a 3" bellcrank.



Examining it, there were two obvious ways to get around this - put a spacer around the end or a pin straight through to keep it from sliding all the way up, or, make the slot deeper. After some decisions about what angle I could tolerate, I determined that the collar or end of the slot needed to be moved about .035 to permit the necessary clearance. I chose to make the slot deeper, which tends to improve the already pretty decent retention, rather than wrap the end of the barrel with glue/wire to push the collar down.



After a little work with the needle file, this is what I wound up with:



It will go just past 90 degrees before hitting the end of the slot, and the slop of the ball in the socket is acceptable. The entire arrangement is nice and free in the directions we care about.

  Here's the before and after:



    Need to put a dab of grease on it at final assembly, but otherwise good to go, I think.

I would also note that there is also a plastic version of otherwise identical design, same thing would work, and I expect it would be just as good for our purposes.

   Brett