I swear everyone of these Harbor Freight Ratcheting Clamps internal handles/triggers are different. There are numerous ones out there, but none seemed to be the right size so I designed my own. To complicate it, the inside pin on one side also broke off.
To resolve the pin issue, I measured the other side and made a new pin that would fit from the outside into the new handle. I had to drill a hole through that broken side that aligned where the old pin was to enable the new pin to be inserted. I then superglued the head of the new pin to the outside of the side frame. It works like new.
I included a few pictures with a measuring tape to help determine if this is the right part for you.
I used PETG for strength and heat since it is stored in the garage. Recommend 25-30% fill on the handle. I did add supports for one side of the hole when printing on its side.
The author marked this model as their own original creation.