Westclox Big Ben and Baby Ben Repair Tips

This page gives some hints about Big Ben and Baby Ben alarm clock repair. For the names of some excellent clock repair books, see the recommended reading page.

Don't use ammonia based cleaner on hairsprings. Use waterless non-ammoniated watch cleaning solution, or use alcohol. Ammoniated cleaners tend to eat away the hairspring material, changing the rate.


I number wheels starting at the main wheel. F and B refer to front or back, and T and A refer to time train and alarm train. For example, T2F refers to the front pivot of the second wheel in the time train (which is the center wheel in a Big Ben or Baby Ben).


These are my preferred lubricants. There has been controversy about using synthetic motor oil for clocks. My experience, and that of others has show that synthetic motor oil works extremely well for clocks. (References Stephen Nelson and Ken Reindel).

Synthetic motor oil types I use:

Oiling Locations:



Use KWM sized bushings, DON'T use Bergeon bushings! Bergeon bushings require a large hole to be reamed, and it looks bad.

I recommend "American System" bushings in KWM sizes, available from the major clock parts suppliers. Example bushing sizes for Big Ben Loud Alarm:

Parts to smooth while clock is apart

  1. Repeat lever where it is pushed by trip spring (Loud Alarm movement)
  2. Trip spring edge which pushes repeat lever aside (Loud Alarm movement)
  3. Trip staff cam where it pushes down on trip wheel
  4. Burnish slot of pallet fork (lever). A sewing needle works well.

Do Before Assembly

  1. Make sure center friction is tight enough.
  2. Oil front center pivot (T2F) if cannon (shuck) pinion is in place.

Check after assembly

Big Ben style 1 case front screws

Originals are 1-56 thread, 1-64 will work as a replacement.

Don't bend the dial tabs on Big Ben or Baby Ben clocks!

Bending them isn't necessary, will cause them to break off if done repeatedly, and makes it a pain for the next repair shop.

Polishing Nickel Cases

Use "Rubin-Brite" metal polish. Produces best polish on nickel that I've seen.

Take the movement out of the case before using metal polish. Thoroughly wash off all metal polish when done.

Removing Time Set Knob on model Big Ben model 75 movement (single key wind introduced in 1956).

Remove movement from case. Bend a brass strip in half and put it over the center arbor between the knob and the back plate. Firmly grasp the center arbor (on top of the brass strip) with Vice-grip pliers. Lever the knob off using 7" diagonal cutters, using the vice grips at the fulcrum.

The regular way of prying off the knob will compress the tension spring, as there is no shoulder on the center arbor. Also, if the movement has an aluminum back plate, it may bend.

Alarm Trip Assembly

The later alarm trip assemblies - the one in which the cam on the trip staff is a steel disc with a cutout, and the trip wheel is steel with a stamped out projection - can be troublesome. I had so much trouble with these parts on a 1970 Big Ben leg model reproduction that I replaced them with the old style trip assembly having the brass finger on the trip staff and a brass trip wheel. This solved the problem of the trip staff being carried around with the trip wheel.

I'm still trying to find a way to make the trip wheel move up and down easier on these steel trip assemblies - please tell me if you have any hints! I've tried polishing the lifting surfaces,and chamfering and smoothing the hole on the trip wheel. You can hold these parts in your hand and tell that the old style works much better than the new style.

Dealing with Glued Hairsprings (Red cement used starting in the 1960's)

The red cement may be dissolved with lacquer thinner to remove the hairspring from the stud. A convenient way to refasten the hairspring to the stud when reassembling the clock is to use orange shellac (in liquid form from a can). This can be removed with denatured alcohol the next time the clock is taken apart.

Jim Galazka has suggested using fingernail polish to glue the hairspring, which is an excellent idea. It is easily available, can be removed easily, and you could probably match the original red color if desired!

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