The phrase "a lever which" is correct and usable in written English.
It can be used when describing a specific type of lever or its function in a sentence.
Example: "The engineer designed a lever which could lift heavy weights with minimal effort."
Alternatives: "a lever that" or "a lever capable of".
In terms of mechanical design, we built a lever, which lacks significant science behind such construction.
You half expected him to pull a lever which would empty a tank of gunge over Lord Hutton's head.
A worker has to pull a lever, which triggers a ticker-tape printout in the control center that identifies the location of the box.
Mr. Scarborough has a regular steering wheel, but he controls the speed with a lever, which also moves the Crab forward or backward.
California's constitution prohibits "Nevada-style casinos with slot machines", fed by coins and operated by a lever, which pay out from the house.
It's all done with the touch of a lever, which locks in place for coring and releases for the core to drop out: Casabella Apple Corer is $9.95 at Sur La Table stores, (800) 243-0852, surlatable.com.com
During a series of trials, the monkeys had a choice: they could pull a lever that immediately released two pellets of food, or they could pull a second lever, which would reveal a richer reward of six pellets, but only after a delay.
A small lever, which converts vibrations into electricity, powers a sensor that takes readings and transmits data.
After defeating the jarl, the adventurers have a chance to pull an iron lever which will transport them near to Snurre's hall from Hall of the Fire Giant King.
The temptation for the I.O.C. is to try to use the Winter Games as a developmental lever, which was part of the thinking behind awarding them to Sochi.
Wordlessly the hangman steps back, places a hand on the lever which operates the trap, and gives a signal to the officers, who release Pascoe's arms.
