[Bucky, when you're as old as these guys, everyone is a kid. He shrugs, a little sheepishly, offering up a smile as he follows "Strongarm" in.]

Met him when I showed up. Answers to Strongarm. And says he got in a misunderstandin'... so... [See what he did there? With the metal arm.] Strongarm, this is Ratchet. Friend I told you about.

[The last is mostly for the human's benefit.]

He's a good bot. You can trust 'im. Okay?