where did the term chop chop come from
Chop chop (phrase) The term may have its origins in the South China Sea, as a Pidgin English version of the Cantonese term chok chok (Cantonese: 速速; jyutping: cuk1 cuk1) which in turn is similar in usage to the Mandarin term k'wâi-k'wâi (Chinese: 快快; pinyin: kuài kuài)[1] or may have originated from Malay.[citation needed]
Riving knife A table saw is typically used for cross-cutting and ripping; cross-cutting slices a board across its grain width-wise, ripping cuts lengthwise along the grain. Various conditions experienced while cutting either way can cause a partially cut board to move, twist, or have the saw blade's kerf close up and bind the blade. Poor blade or fence alignment, operator error, or pre-existing stresses in the wood released by cutting may cause these different and dangerous conditions. A riving knife rides within the kerf, pivoting on the saw's arbor in relation to blade height, to maintain an even gap between the two cut sides of the board, preventing jamming which could cause the stock to be forcefully ejected rearward toward the saw's operator.[1]