Sorry to hear of your loss, Robert. Your question is interesting; I flipped through the gospels (i.e., Matthew, Mark, Luke, and John) to look for passages that mention working men and might have been read at the earlier funeral. These are my suggestions:

Matthew 7:24-27: a wise man builds his house upon a rock so that it withstands the weather, whereas a foolish man builds his house upon the sand and it is destroyed in the first storm.

Matthew 13:1-23: a farmer sows seeds on four different kinds of ground, and the crop grows or not depending on how receptive the soil is. Jesus goes on to explain that the seed is a metaphor for his message.

Matthew 18:10-14: if the owner of a hundred sheep loses one, he leaves the 99 to search for the lost one, and is happier about finding it than about the ones that never wandered away. See also John 10:1-16 about the good shepherd who calls the sheep by name, and the sheep know his voice and follow him. When a wolf threatens the flock, a hired hand will run away but the true shepherd will die to protect the sheep.

Luke 5:1-11, or Mark 1:14-20: Jesus approaches 3 or 4 fishermen as they work and calls them to be his disciples.

Matthew 11:28-30: a famous quote from Jesus is "Come unto me, all ye that labour and are heavy-laden, and I will give you rest. Take my yoke upon you, and learn of me; for I am meek and lowly of heart, and ye shall find rest unto your souls. For my yoke is easy, and my burden is light." This passage is in Handel's Messiah as an alto/soprano duet; the soprano sings the verse I just quoted, and the alto sings a quote from the Hebrew Bible which is also related to labour. (Isaiah 40:11: "He shall feed his flock like a shepherd: he shall gather the lambs with his arm, and carry them in his bosom, and shall gently lead those that are with young.) If your father wasn't religious, maybe having the Biblical reference in song rather than as a reading would feel more appropriate, if you like this passage and think it's possible that it's the one your dad liked. Harder to arrange on short notice, though, but if you know a couple of female soloists, there's a good chance that they'd be familiar with the piece.