Stem Sizes

You can use below table to determine the tap size of your watch stem. Measure the diameter the threads on the stem (use a vernier caliber) and use the table below to find the corresponding tap size.

Stem Thread DiameterTap Size
.60 mmTAP 13
.70 mmTAP 12
.80 mmTAP 11
.90 mmTAP 10
1.00 mmTAP 9
1.10 mmTAP 8
1.20 mmTAP 7
1.30 mmTAP 6
1.40 mmTAP 5
1.50 mmTAP 4
1.60 mmTAP 3
1.70 mmTAP 2
1.80 mmTAP 1
1.90 mmTAP 0