Although his name did not appear in the show's opening and closing credits, most Lost In Space fans know that he was the robot but not the voice; Dick Tufeld was the voice.
"He always said he got the job because he fit in the robot suit," said June Lockhart, who played family matriarch Maureen Robinson.
Although May didn't provide the robot's distinctive voice (that was done by announcer Dick Tufeld)
He was particularly fond of his Robot role, once saying he came to consider the suit a "home away from home."
Lockhart said May wore the suit for hours at a time and learned the lines of every actor in the show so he would know when to respond to their cues. Because it wasn't easy to get in and out of the suit, he kept it on during breaks.
"He was a smoker," Lockhart remembered. "From time to time (when he was on a break), we'd see smoke coming out of the robot. That always amused us."