March 2018

T. D. 103 Hamilton Watch Company LANCASTER,PENNSYLVANIA SUBJECT: Semi-Friction Balance Jeweling NOTE: This type of balance jeweling will be found in grades 986A, 987 987E, 987F, 989 and 912. Fig. 1, shows a cross-section of the movement through the center line of the balance. This drawing represents the balance bridge, pillar plates, hole jewel and […]

7-29 1000-1-30-31 1000-5-25-35 1000-6-15-36  Revised 1000-4-25-38 1000-9-27-39 Hamilton Issued about 30 technical documents (TD’s) prior to WWII. I plan to use post each one in a readable format. Age rendered the TD’s difficult to read and understand.  Grades 989, 989E, 995, 995A, 997, 980, 980A, 980B, 982, 987A are jeweled by an improved system, absolutely

Hamilton issued about 30 technical documents (TD’s) prior to WWII. The company released one each time they produced an innovation. I haven’t found the entire series. I’m guessing from the titles that a later TD caused Hamilton to revoke a previous one. For example, we haven’t found TD 105 & 106.  If we find those sheets, we’ll