1st Edition Fundamentals of Torque
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1st Edition is “Fundamentals of Torque”.
Torque is the power of circulating objects.
Torque is called in many ways, such as「Moment of force」, 「Moment of circulation」, and
「Tightening Torque」especially relating with screws tightening.
The magnitude of torque force is sum of length of circulating tool （L） multiplying given force （F）.
As the chart above, the sum of the torque for the 1m wrench applied by 50N （About 5kgf） is showed below.
T = F （50N） × L （1m） = 50N•m （About 5kgf•m）.
When it comes to torque unit, these unites such as kgf•m and kgf•cm cannot be used anymore, because “Method of
Mesurement” carried out in 1993 changed these units into “N•m”
decided by SI unit （ISO international unit）. However, products of yard and pond unit （Non-legal measuring unit） can
be used in some cases.
1•Nm is 0.10197kgf•m and 1 kgf•m is 9.8067 N•m.
As a guide to match those units, it is recommended that 10N•m should be taken as 1kgf•m for rough understandings.
For example, it is necessary for 1m wrench applied by 5kgfm force.
However, 1m wrench for 5kgf is too long, so it is lead to the fact that you should choose more practical wrenches in length.
As there are （km） and （cm） for length unit, there are kN･m and
cN･m for torque unit. cN･m is especially used for tightening machine screws.
1cN･m＝0.01N･m or 1N･m＝100cN･m