A expressão do título deste post significa literalmente colocar os pingos nos is e cortar os ts e adaptando para a língua portuguesa fica simplesmente colocar os pingos nos is, fazer algo com bastante exatidão. Veja alguns exemplos:
She writes highly accurate reports – she always dots her i’s and crosses her t’s.
Ela escreve relatórios altamente exatos – ela sempre coloca os pingos nos is.
Our manager is really picky. We need to dot all the i’s and cross all the t’s before he comes.
Nosso gerente é muito exigente. Precisamos deixar tudo certinho antes de ele vir.
Veja a origem dessa expressão em inglês, do site www.joe-ks.com.
Crossing the T has also become a naval term. A naval engagement fought in the Surigao Straight during the Battle of Leyte Gulf, which is in the Philippines, illustrates crossing the T. That battle (Leyte Gulf) marked the end of the Japanese navy.
It was also the strangest naval battle in the war. Both sides were totally confused as to the disposition of enemy forces and both commanders made mistakes that seriously jeopardized their objectives. Admirals Kincaid and Halsey had the advantage of numbers and luck and won out.
Warships of the era had guns mounted in turrets distributed over the ship. Their ability to fire in the direction the ship is pointed is limited to the front most turrets, rendering the remaining guns useless for firing forward. However when firing perpendicular to the ship, all turrets can be rotated and used.
The Japanese ships were caught in a single file line. The United States ships were positioned at the head of the line in a T fashion. This formation is known as crossing the T in military circles.
Having crossed the T, the U.S. ships could point all the ship’s guns towards the Japanese ships making it easy to fire on them. The Japanese ships had the considerable disadvantage of having to fire straight ahead.