Lead = No. start x pitch

Lead = Pitch

Lead = 1/2 pitch

Lead = 1/3 x pitch

1.50 mm

3.00 mm

4.50 mm

6.00 mm

0.5 x Pitch

equal to pitch

Pitch / 0.5

2 x Pitch

100

127

140

135

Diameters decreases helix angle increases

Diameters decreases helix angle decreases

No change in helix angle if diameter increases

No change in helix angle diameter decreases