Glossary of watchmaking

Index for flat balance springs

Raquette pour spiraux plats | 緩急針(平ヒゲ用)/カンキュウシン(ヒラヒゲヨウ) | 扁平摆轮游丝微调器

An index that is often fitted with a screw or cam so that it can be adjusted by a very small amount for fine-tuning. The spring passes through the space between the curb pin and the boot.