Dont let any one tell you these are no good - we been flying them on trainers and Sr Kadets for our RC Skydivers and have never had a problem - we change motors all the time and dont even use locktight - we just check then every couple flights and very seldem have to tighten a screw - they work and work well
just use thwem and let all the negative stuff go in one ear and out the other

also a couple flyers that do 3d use these mounts so they can change motors fast as they may change 3 or 4 motores at the field to check out dif ones

we yus anywhere fron 40 to 60 size motors and a few Mag 70 4 strokes
\don