Warranty.
Introduction.
Gravity Settings
Calculate Pendulum Length
Change in length.
Pendulum beats from info on clock
plates
Calculate Wheel diameter and depth of
cut
Wheel Module:
Cutting speeds
Calculate how much to
shorten an overlength mainspring.
Moonphases
The document 'clockaid.htm' and the accompanying help page 'caiddoc.htm' are supplied on an 'AS IS' basis without any warranty of any kind. The entire risk of the quality and accuracy rests with the user. Whilst ever effort has been made to ensure that the information on these pages is correct, should any part of the main page or help page prove defective, the user will assume the entire cost of all necessary repair, servicing or correction.
Whilst the copyright of the program remains with the author, the pages may be freely copied and distributed, provided that you do not alter or remove either of the pages listed above. You may not make any charges for these pages what so ever.
These pages have been written so that should run on any browser that will run JavaScript. It has been tested on Microsoft Internet Explorer v4.01 and Netscape navigator V4.01.
Clockmakers Aid has been written to provide a quick and easy way of performing routine calculations needed in a clockmakers workshop. It is based on some of articles published in the British Horological Institute's magazine 'Horological Journal' as well as the BHI's Correspondence Course. Modifications were made to the program based on the suggestions of Mr I Thorpe, these suggestions were accepted with great appreciation and have improved the usability of the program.
The program will perform calculations for gear cutting operations, pendulum length calculations, cutting speeds, mainspring calculations and will show approximate moon phases. It is strongly advised that you make a working copy of these pages for normal use, and store the masters in a safe place.
The pendulum calculations are based on an article and formulae published in the August 1988 edition of the 'Horological Journal' by Mr R.C. Barclay of the USA. Additional material was used from the British Horological Institute's Correspondence Course. The Wheel calculations used in these options are based on an article written by Eliot Isaacs FBHI and published in the October 1988 edition of the BHI's 'Horological Journal'. The cutting speeds were taken from the Presto Cutting tools advisory booklet. The mainspring calculations formulae are from the British Horological Institute's Intermediate correspondence course.
The pages have been designed to be stand alone pages so that they can be saved in a convenient place, such as the desktop, and called at any time without having to log on to the Internet.
If you do not live in the UK, then you will need to change the gravity setting to your local setting. The table below gives suggested settings for various places in the world.
Town | G in cm/sec/sec |
---|---|
London | 981.2 |
Aberdeen | 981.7 |
Belfast | 981.5 |
Edinburgh | 981.6 |
Manchester | 981.4 |
Montreal | 980.7 |
New York | 980.7 |
Paris | 980.9 |
Toronto | 980.5 |
Washington | 980.1 |
This option is used to calculate the theoretical length of a simple pendulum required to maintain timekeeping on a clock that has a known gear train. The length of the pendulum will then be given in cm
The formulae used are:-
Vibrations per minute
V =(CW x TW x EW x 2) / (TP x EP x 60)
where, V = Vibrations per minute
CW = Count of Centre wheel teeth
TW = Count of Third wheel teeth
EW = Count of Escape wheel teeth
TP = Count of Third pinion leaves
EP = Count of Escape pinion leaves.
Theoretical pendulum length
L =(T2 x G)/ (PI2)
where L = Theoretical length of the pendulum
T = Time of vibration (seconds)
G = Gravity in cm/sec/sec
PI = 3.1416
This option is used to calculate the change in a pendulum's length to correct its timekeeping error. It is used when a clock has been running for a known length of time with a test pendulum, and it has not kept