FAQ: The locking pin and control arm I ordered don’t seem to fit together

We’ve been receiving a few questions from astute customers who have ordered a tailwheel Locking Pin along with one of our Control Arms and noticed that the two parts don’t totally mate together when assembled. A customer sent us this image to demonstrate their concern.

In fact, this is how these parts should look if assembled together, but keep in mind that there are more pieces to this assembly. When these parts are assembled together with the tailwheel fork and mounting socket, the pin is limited in its extension not by the keyway in the control arm but by the groove in the locking pin, as shown below.

The keyway is only rounded because it’s machined with a rotating tool, so don’t assume that its profile needs to match the locking pin. The blunted nose on the locking pin is intentional and ensures that the pin can attain maximum side-to-side engagement with the slot. 

In other words, the relevant fit between these parts happens on the straight sides of the pin and keyway, which are highlighted in pink in the picture below. This is the area that connects the tailwheel steering to the pedals. Since the pin can only stick out as far as the mounting socket allows it to, blunting the pin (instead of having a rounded nose on it) allows the most contact between the straight sides. Rounded pins sometimes cause an issue where the tailwheel can unlock at an inappropriate time. 

For a visual reference of how all of these parts fit together, see our tailwheel assembly video here: https://www.youtube.com/watch?v=LkBz3UqRanQ

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