[Markus K.]

the small tubes were pressed into the side-parts, receiving the roller-tubes first. Then connected with the bolt through the small tubes, the bolts were loctited into the left side parts. The last bolt is secured with a little worm screw placed under a chain shoe (1.st picture). As a reminder for the invisible chain lock there is a small center boring in the lock bolt.
The shoes were made of steel while the side parts were made out of aircraft aluminum.