An architect was discussing changing pricing during negotiations and uttered this malaphor. I believe it is a combination of “sharpen our pencil” (give a good deal) and “tighten up” (to become more restrictive or miserly). “Crunch the numbers” (doing calculations) might also be in the mix, although it doesn’t fit within the context. Yvonne Shipley suggests “tighten our belts” might also have been on the speaker’s mind. I think that is very possible. A shout out to Jim Washabaugh for hearing this one and passing it on!