A replacement part for inner trolley for liftmaster/chamberlain garage door, this part hold both ends of the chain and the safety lock that holds the garage door arm.

this is one part of the connection system, i found the 2nd part was already created by Skrotax and here is the link for it incase you are looking for the 2nd part as well https://www.thingiverse.com/thing:3314495

The reason behind making this part was, the og part broke on both garage door i have, and when i got to contact the local supplier they quoted me 10 times the price of the part, although liftmaster has it for 8 USD on their website, but unfortunately the website does not ship to my location, so i had to improvise and created this part.

this part has some miner differences from what the original part, due to 3D print restriction that cause weak spots, but it surely works perfectly fine, it has been working for almost more than 3 years, at least i use the garage door twice a day, not to mention the heat climate where i am at.

Important Tips:

• do print with little bit more heat than recommended to guarantee layers adhesion.
• bed plate heat is highly recommended to keep the 1st layers flat.
• do please use a good quality filament because this part faces a lot of pulling force.
• lastly do use industrial grease on the part itself when you do the installation, this will reduce the pulling stress of the garage door = less stress on the part (keep the garage door chain and channels maintained for longer life span).

This part was printed and tested using PETG.

Print setting:
Filament type: PETG
Layer Height: 0.2
Infill: 100%