Since when do presidents not put their hand on the Bible.

He made up for it by immediately signing something like 130 executive orders to begin reversing the damage done to this nation by the Dem's dementia-puppet president.

The Chief Justice rushed it, the 20th Amendment says the new president is sworn in at 12:00

The use of a Bible for taking the oath of a US office is not a requirement outlined in the constitution.

Since when do presidents get sworn in without putting their hand on the bible?

It might be tradition, but it is not a requirement. Witnesses are sworn in without the Bible in courtrooms every day.

U.S. Constitution
Article II
Section 1
1.8 Before he enter on the Execution of his Office, he shall take the following Oath or Affirmation: -- "I do solemnly swear (or affirm) that I will faithfully execute the Office of President of the United States, and will to the best of my Ability, preserve, protect and defend the Constitution of the United States."