I was just wondering if it is all right to use a 4-40 threaded pushrod on my control surfaces with one end using a Du-Bro ball joint and the other end using a Du-Bro Kwik link?

I don't know much about ball-joints but I would go with a regular clevise if I were you.

Ball joints are good but i saw one come off today,it's your choice but i think a clevis would be better.

if you want to use ball links go with the sullivan they are spring loaded and will not come off accidently.

What size plane? 2-56 rod is plenty for a .40 -.60 size plane. 4-40 rod really isn't needed and will add a little weight.

I prefer good ball links on all my planes, especially the 1/4 scale or larger. They are more precise and much more reliable than clevises or zbends. You should have no trouble with the use you describe.

If you are referring to the Dubro links that thread on and have a bolt going down through a ball socket into the control horn. Go right ahead. I am going to use them on my RCM Advanced Trainer that I am currently building. They are very strong and precise. If you mean a ball and socket type hook up I agree they are better off not being used. Sullivan's look ok but i still would not trust them. Good luck.

Mark Shuman

BTW go ahead and use the 4/40 stuff. It is a little heavyer yes. But much stiffer and all in all would make the plane more responsive.