Solder Help Edited Flex Joint & Seat

I had issues with the cylinder seat and cylinder Joint as the end of the joint wouldn't sit tightly into the back of the seat meaning it kept coming apart, to be honest i see no reason apart from aesthetics and 1 Joint to start and 1 Seat to Finish the arm to have the parts separate. this being said i used 123D Design to create a modified version of this and it seems to have done the job. use the same settings as the source by Faraa. and have printed and tested the item n it works perfectly. I b