i picked up making rc airplanes after stumbling on to the flite test youtube channel so ive made quite a few of there planes from foam board, i was trying to do it as cheaply as i could so only spending money on stuff i absolutely had to. it was also around the same time i first got a 3d printer an seemed like a easy thing to make with me just starting to learn to make 3d models using tinkercad. i never shared them cause i thought they was to simple of a thing to share but ive not seen anyone else print them, maybe cause they are so cheap to buy but for anyone else who is as cheap as me, here they are. i used m2 threaded inserts to make sure they get as strong of a bite as they can. i also added a version that isnt for thread inserts so u can just cut the threads into the plastic, ive not tested this myself so i cant say how well it works but i made alot of other stuff that only used plastic threads an they hold pretty good as long as u dont over tighten an strip them but i made some with added material on the ends where the inserts will go but u can manage to get them in the ones without the added material. what is pictured was the very first version i made an at least 2 yrs old, picture was taken at the same time of me posting this an they have held up great so the ones with added material should do just as good or better unless it causes clearance issues ive not tried all versions. whats pictured is no added material with inserts on both ends an the others i only added it to the side that locks the linkage. hope someone else finds it useful.