Albert Barnes Commentary Judges 16:14

"And she fastened it with the pin, and said unto him, The Philistines are upon thee, Samson. And he awaked out of his sleep, and plucked away the pin of the beam, and the web." — Judges 16:14 (ASV)

And she fastened it with the pin ... - The meaning of the verses seems to be that the seven long braids, in which Samson’s hair was arranged, were to be woven as a woof into the threads of a warp. This warp stood prepared on a loom in the chamber, and Delilah fastened down this loom with a pin to keep it firm and immovable. But Samson, when he awoke, tore up the pin from its socket and went away with the loom and the pin fastened to his hair.

The beam - Rather, the “loom,” or “frame.” The beam is the wooden revolving cylinder on which the cloth is rolled as fast as it is woven. The Hebrew word for this, found in 1 Samuel 17:7, 1 Chronicles 11:23, and 1 Chronicles 20:5, is quite different from the word used here.