Southern Machinery provides professional SMT peripheral equipment.

IM Component Lead Hole Specifications

2023-02-09 17:51:22

Component Lead Hole Specifications


PC boards should be punched for component lead insertion to the following recommended hole diameters.


HOLE DIAMETER = LEAD MAXIMUM DIAMETER (φd for round leads, φd3 for rectangular leads) + 0.483 mm

(0.019″) ±0.08 mm (0.003″)


Hole sizes less than the recommended size may result in a degradation of insertion reliability while holes that are greater than recommended may result in loose components in the printed circuit board.


Unguided leads require larger hole-to-lead relationships. For triangular or in-line layout (such as potentiometers and SIPs), PC boards should be punched for the unguided lead(s) to the following recommended hole diameter.


HOLE DIAMETER = MAXIMUM LEAD DIAMETER + 0.584 mm (0.023″) ±0.08 mm (0.003″)



For maximum lead diameter, use φd for round leads and φd3 for rectangular leads. (Refer to the notes for “Two- Leaded Component Specifications” for definitions of φd and φd3.)


For further considerations and examples of lead-to-hole relationships, see the Cut and Clinch sections of this GS for the particular cut and clinch desired.


Holes used for board error correction should be 1.0 mm + 0.5 mm (0.040″ + 0.020″). Plated holes or translucent PCBs may affect performance.

Recommended Lead Hole Span


Dual Span Machines


Insertion performance is maximized by considering the jaw tooling design when laying out the PC board hole patterns (the jaw clamps secure the component leads against the fixed surfaces of the jaw guide). In order to achieve the best results, the insertion hole spans in the PC board should be designed at 2.54 mm (0.100″) (for 2.5 mm components), one lead diameter plus 4.5 mm (0.177″) (for 5 mm components). Use the following table for a reference.




Lead Diameter

Recommended Lead Hole Span

Lead Diameter

Recommended Lead Hole Span

0.36 mm (0.014″) 2.34 mm (0.092″) 0.36 mm (0.014″) 4.85 mm (0.191″)
0.41 mm (0.016″) 2.37 mm (0.094″) 0.41 mm (0.016″) 4.9 mm (0.193″)
0.46 mm (0.018″) 2.44 mm (0.096″) 0.46 mm (0.018″) 4.95 mm (0.195″)
0.51 mm (0.020″) 2.49 mm (0.098″) 20.51 mm (0.020″) 5.0 mm (0.197″)
0.56 mm (0.022″) 2.54 mm (0.100″) 0.56 mm (0.022″) 5.05 mm (0.199″)
0.61 mm (0.024″) 2.59 mm (0.102″) 0.61 mm (0.024″) 5.11 mm (0.201″)
0.66 mm (0.026″) 5.16 mm (0.203″)
0.71 mm (0.028″) 5.21 mm (0.205″)






These dimensions apply only to holes for leads that are captured by the insertion tooling. All remaining holes should be drilled according to component manufacturers’ specified spacing requirements.


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