In addition to the trolley itself, the parts that make it up are the grippers, and their articulation, which has two axles. One, longitudinal, the pinch axis, allows the grippers to spread then to grab a semi-trailer or a swap body; the other, perpendicular, the lifting axle, allows the grippers to be placed in the working position or in the rest position when working with containers and twist locks.
I wondered for a moment whether to make these articulations functional. To do so implied an increased risk of weakness. Not to do so led to designing two different parts: one representing a trolley with grippers at work, the other with grippers at rest. I opted for the first solution.
These accessories are generally small and practically require using a magnifying glass. First the gripper’s stand. A notch is provided in the 3D part. CA gluing.
Then, the stand rest and the trolley’s third support. These parts are positioned using pins on the trolley. You can see that the trolley is poorly cleaned. While looking at this photo, I realized this problem. I had to dismantle the accessories already in place to do the cleaning again. Fortunately, CA glue is easily dissolved by acetone.
The problem here is twofold: the axles should enter their housing without forcing too much (risk of breaking the resin), but, at the same time, the articulation should not have too much clearance, to allow the grippers to be positioned at one’s will.
The solution that I found is to adjust the hole diameter with a carbide drill bit, to the exact axle diameter, here 0.8 mm, by hand, very slowly and without insisting: I stop the rotation just before getting through.
Click the picture to zoom.
To insert the axle, quite short (4.5 mm), I place it in a hand-held drill…
… Then I push it in carefully before releasing hand-held drill and finishing the positioning.
As a result, the grippers hold in the air by themselves.
Grippers at rest.
Grippers at work.
Grippers at rest, detail.
Grippers at work, detail.
Et voilà, it remains only the decoration, painting and installation of decals. But this is another story.