G.D.T. Standard
Dimensions and Tolerances
Types of dimension:
• (43) this is a reference dimension, note the brackets
• 43 this is a whole dimension, there is no decimal stop/dot
• 43.0 one place dimension, there is one decimal after the stop/dot
• 43.00 two place dimension, there are two decimals after the stop/dot
• 43.000 three place dimension
Tolerances:
o (43) reference dimensions do not have an applied tolerance
o 43 +/- 2mm, this gives a dimension bandwidth range of 41 to 45mm
o 43.0 +/- 1.0mm, dimension bandwidth range 42.0 to 44.0mm
o 43.00 +/- 0.50mm, dimension bandwidth range 42.50 to 43.50mm
o 43.000 +/- 0.010mm, dimension bandwidth range 42.090 to 43.010mm
Note: the more decimal places, the tighter the tolerance bandwidth
Stated dimensions:
Sometimes a dimension bandwidth is stated in the dimension text:
➢ 39.3
38.3 this means the dimension bandwidth is 38.3 to 39.3mm
➢ Ø 54.98 +/- 0.05 means a bore (hole) of diameter 54.93 to 55.63mm
➢ 2x Ø 54.98 +/- 0.05 means two bores (holes) of diameter 54.93 to 55.63mm