Fusee Clock Movement

This movement was handed to me in a box and the words “I rescued it years ago and since then it has sat in this box under my bench.  You may be able to do something with the brass.”  Inside the box was a complete wreck of a movement minus hands and a rather coarse mahogany case with broken door glass.  All covered in years of dust.

Inscribed Pendulum Bob

Inscribed Pendulum Bob

It quickly became apparent that the movement had originally been well built and regularly maintained as scratched on the pendulum was the name ‘St Pauls Church’, but of which Parish was not stated.   At some point it fell on hard times.  I can only assume that there was an intention to reassemble the movement in the accompanying case.  Certainly the two were not originally together.  Dare I venture they had limited clock repairing / engineering skills and examination of the case showed their carpentry skills were even less;  the case was broken up for firewood.

Placing the movement on the bench after cleaning and oiling the following inscriptions concerning the movements service history could be discerned on the body that would sit behind the dial:

Oct 8th 1973 W.H. Coulridge, PLW 21 in 1978, 2/10/1880 W.H. Savery, 23/9/85 E.J. Hustable,        ?/87 E.J. Hustable and 30/1/92 YB.

It looked like the clock ceased to be used for its original purpose after 1992.

Winding the clock up it ran for two rotations of the escapement wheel and then stopped.  Careful examination revealed the following problems:

  1. The escape wheel had extended ‘fingers’ on several of the teeth due to wear.
  2. The main shaft out to the hands was not running true.
  3. The collar at the rear of the Fusee cone was not running true and fouled the centre wheel on the centre shaft every full rotation of the Fusee.
  4. The pendulum bob had been altered with a much longer spring strip and where someone had tried to drill holes through to attach to the bob it had been heated to remove the temper.  Thus it was no longer a spring strip.

Taking each fault in turn they were rectified as follows:

Deadbeat Escapement

Deadbeat Escapement

The escape wheel was held in the lathe and by carefully positioning a guide against each tooth the ‘run out’ could be established.  Using a very fine needle file the ‘burrs’ were carefully removed until the wheel ran true again.

The main shaft was actually broken where it ran through the end plate to the hands.  My guess is the clock had been dropped and the extension of the shaft to drive the hands took the fall.

 

New Main Shaft

New Main Shaft

New Shaft Sleeved Onto Old

New Shaft Sleeved Onto Old

This could have been a show stopper, but I solved the problem by cutting off the remains of the bearing and then ‘sleeving’ over the remainder of the centre shaft and turning a new bearing and tapered extension for the hand gearing.

 

Correct Clearance

Correct Clearance

Releasing the tension in the main spring I removed it and the Fusee.  I could see from all the scratches on the Fusee’s collar and the retaining brass spring clip that this had been removed previously.  Removing it revealed the problem.  Where the steel line had been attached to the Fusee it had not been undertaken neatly which meant that the soldered knot stood proud preventing the collar from sitting flush.  Careful cleaning up of the solder solved this problem and now the plate sits true.

 

Pendulum In Place

Pendulum In Place

Pendulum Suspension Point

Pendulum Suspension Point

The pendulum bob was solved by removing the spring steel and reattaching an appropriate brass rod.  A piece of spring steel was then attached to leave a free length of 5/16” between the two suspension points.

 

The mechanism was reassembled and set up so that it was level both fore & aft and left to right.  Winding up the main spring the clock sprang (no pun intended!) into life.  The remaining adjustment was to get the shaft holding the anchor on its ‘sweet spot’ by adjusting the two limiters on each end of the bearing.  Finally the movement runs very sweetly.

Brass Hands

Brass Hands

Clock Hands were absent when the movement was received, but to test the time keeping a minute and hour hand were needed.  The design was kept simple and they were cut out of 0.036” brass.  The hour hand was silver soldered to a suitably turned brass collar which fitted tightly over the outer brass gear wheel shaft.  The minute hand sat on a square shaft 0.0134” A/F located on the end of inner brass gear shaft.  To locate the hands in position they are usually pinned through the centre shaft.  However, I decided to thread the end 8 ba and use a blind nut & washer.  I don’t think they will work loose.

Dial Face With Brass Hands

Dial Face With Brass Hands

A cardboard dial was drawn out and temporarily attached using Blu-Tack against which its timekeeping could be checked .

Click to download a 1 minute clip WMV file of the movement working.

So that is the story of a Fusee movement returned to the land of the working.