The original 'Clockmakers Aid' was published as a DOS program in 1988 and was intended to provide a quick and easy access to the calculations that you only need occasionally but when you need them you need them right away without the hassel of searchin your library for them. This lated version has been written as an HTML page with no additional graphics so that it can be saved on your desktop and called whenever it is needed. I hope you find this version as useful as the original 2 versions.
To keep this page self contained the normal link buttons have been omited. To go to the web site, click the link below
British Horological Institute Web Site Clockaid documentation
These pages have been tested on Microsoft's internet Explorer V4.01 and Netscapes Navigator 4.0
Pendulum details from a known gear train Change in Pendulum Length to correct inaccurate timekeeping Theoretical beats per hour for a pendulum length stamped on a clock
Wheel blank diameter and depth of cut Wheel module Cutting speed
The amount to shorten an overlength mainspring
Show approximate current moon phase
To check the timing of a clock or watch, you need to know the beats per hour. This page will allow you to enter the wheel counts and then it will show the beats per hour. There is no error checking, so make sure you enter the correct figures.
For a 3-wheel train, leave the FW and FP values at 1.
Enter counts for:- Centre wheel teeth (CW) Third wheel teeth (TW) pinion (TP) Fourth wheel teeth (FW) pinion (FP)(* See Note) (* If you don't have a 4th wheel in your clock train leave the values as 1) Escape wheel teeth (EW) pinion (EP)
Results
Back to menu View Manual
Use this option after you have run the timepiece for a test period and noted the timekeeping error over that test period.
Duration of test period (ie. 36.5 hours) Hours Error found during test Minutes Lost Gained Beats per minute or time of pendulum swing in seconds Results
On some clocks there is a theoretical pendulum length stamped on the back plate. With French clocks, the unit of measurement is Pouces with the whole number being to the left of the pendulum and the decimal to the right. On the more modern European clocks the theoretical pendulum length is given in cm. Thes figures can help in the setting up the rate of the clock.
Enter the unit of measurement Pouce cm Enter the length stamped on the back plate Results
These calculations will help prepare the blank and cutting machinery for manufacturing a new wheel or pinion. The correct depth is best found visually, adjusting the cutter in until the correct tooth shape is formed.
Module Required Number of Teeth
This option will help you find the correct cutter to make a replacement wheel or repair an existing wheel. The correct depth is best found visually, adjusting the cutter in until the correct tooth shape is formed.
Wheel Diametermm Number of Teeth
Find the suggested optimum rpm for machining metals. The rpm's are based on the assumption that sharp High Speed Steel tools are used. If you are drilling, I would suggest that you reduce the suggested speed by about 20%.
Diameter of work or cuttermm Material Aluminium Brass Bronze Cast Iron Copper Mild Steel Soft Iron Silver Steel Stainless Steel
In the UK, mainsprings are bought by specifying the barrel diameter, thickness and width. Sometimes to get the correct thickness, a larger barrel size will need to be ordered. The spring supplied will then be too long. This page will calculate the approximate length that needs to be removed from the mainspring supplied.
Calculate amount of spring to be removed. Enter supplied Barrel Diameter: mm Mainspring thickness: mm
Enter the actual Barrel Diameter
The amount of spring to be removed is mm
Within 2 days, today is day in the moons cycle. The next new moon will be in approximately days time.