Pegas puntir

Pegas puntir atau bandul puntir (bahasa Inggris: torsion spring) adalah sebuah pegas yang bekerja dengan memuntir ujung di sepanjang porosnya. Dengan kata lain, ia adalah alat elastis fleksibel yang menyimpan energi mekanis saat alat tersebut dipuntir.

• Gray, Andrew (1888), The Theory and Practice of Absolute Measurements in Electricity and Magnetism, Vol.1, Macmillan, hlm. 254–260 . Detailed account of Coulomb's experiment.
• Charles Augustin de Coulomb biography, Chemistry Dept., Hebrew Univ. of Jerusalem, diarsipkan dari versi asli tanggal 2009-08-06, diakses tanggal August 2, 2007 . Shows pictures of the Coulomb torsion balance, and describes Coulomb's contributions to torsion technology.
• Nichols, E.F.; Hull, G.F (June 1903), "The Pressure due to Radiation", The Astrophysical Journal, 17 (5): 315–351, Bibcode:1903ApJ....17..315N, doi:10.1086/141035 . Describes the Nichols radiometer.
• Torsion balance, Virtual Geoscience Center, Society of Exploration Geophysicists, diarsipkan dari versi asli tanggal 2007-08-18, diakses tanggal 2007-08-04  Parameter |url-status= yang tidak diketahui akan diabaikan (bantuan). Description of how torsion balances were used in petroleum prospecting, with pictures of a 1902 instrument.
• "Charles Augustin de Coulomb", Encyclopædia Britannica, 9th Ed., 6, Werner Co., 1907, hlm. 452 

Wikimedia Commons memiliki media mengenai Torsion springs.

• Torsion balance interactive java tutorial
• Torsion spring calculator
• Big G measurement, description of 1999 Cavendish experiment at Univ. of Washington, showing torsion balance[link broken]
• How torsion balances were used in petroleum prospecting (web archive link)
• Mechanics of torsion springs. Web archive link, accessed December 8, 2016.
• Solved mechanics problems involving springs (springs in series and in parallel)