Will the addition of bushings decrease the value of my clock?

​I have had several customers ask me this.  Sometimes they have been told by “clockmakers” that adding bushings will devalue the clock.  These same “clockmakers” then proceed to take a prick punch and scar up the movement with abandon.  What is the truth about bushings?
A clock in mint condition is always more valuable that a clock in excellent condition.  That is because mint means it is in the exact condition it was when it was made, or “new and in the box.”  Mint condition clocks are more valuable because they are so rare.  A mint condition clock will have no wear, so it will have no need for bushings.  Adding bushings to a mint condition clock would decrease the value of the clock because the clock would no longer be in the condition it was in when it was made.
Most antique clocks have been used, but they may still be in very good condition.  However after 100, 200, or 300 years of use, some wear is bound to occur.  Repairs are expected, and well done repairs do not detract from the value of the clock.  Bushings are recognized by the American Watchmakers-Clockmakers Institute as the best method for correcting worn pivot holes.

Pivot holes wear because a clock needs oil for the gears to turn freely, but the oil will trap dust from the air.  The dust accumulates in the oil and acts as a grinding compound.  Eventually, the pivot hole becomes worn on the side of the hole that the pivot presses against.  As the hole becomes more oblong the gear slips out of alignment with the other gears.  The teeth don’t mesh properly, and friction increases until the clock stops.
To correct worn pivot holes the American Watchmakers – Clockmakers institute recommends installing a bushing (a brass or bronze cylinder with a hole in the center resembling a bead).  The original hole is opened up.  Care must be taken to keep the larger hole centered on the original pivot hole.  Then a bushing is pressed into the hole. 
The alternatives to installing bushings are as follows:

1. Leave the clock in non-working condition (this decreases the value of the clock significantly).
2. Use a hole-closing punch to close the hole. A hole-closing punch is circular and pushes the brass surrounding the hole down and into the hole.  The advantages to this technique are that it work hardens the brass making it more resistant to wear and that it is very hard to see as long as the pivot hole isn’t too badly worn. The disadvantages of this technique are that the brass has been compressed so that there is less bearing surface against the pivot and that the unworn sides of the hole compress to fill the original pivot hole while the worn side isn’t compressed into the original hole.  The clockmaker must open the hole back up to accept the pivot, and must be careful to remove most of the brass from the sides of the hole that were not worn.  This is tricky.
3. Use a prick punch to compress the brass only on the worn side of the pivot hole.  The advantage of this is that the clockmaker leaves the unworn sides of the pivot hole alone and uses the punch to fill in only the worn side.  The disadvantages are that the repair is unsightly, compresses the top of the hole more than the bottom and leaves a hole that is not round.  The bearing surface is reduced to a few brass lumps on the edge of the pivot hole.
4. Install ball bearings.  The advantage of ball bearings is that they greatly reduce friction.  The disadvantages are that they are significantly different from the original character of the clock (it is not appropriate to put ball bearings in antique clocks), ball bearings may be difficult to clean the next time the clock is repaired, replacement ball bearings may not be available in the future, and because the size of the hole required to accept the ball bearing is much larger than the original pivot hole, it is very difficult to make sure that the bearing is in exactly the same position as the original pivot hole.

Badly installed bushings can decrease the value of the clock.  If the bushing hole doesn’t coincide with the original pivot hole, the gears will be misaligned which will result in poor performance of the clock.  This can detract from the value of the clock. A bushing machine does not automatically center a hole, especially if the pivot hole is worn out of round. The clock maker should make sure that the original center of the pivot hole is marked and must be careful to keep the hole centered when opening it up to receive the bushing.  Bushings should be the appropriate size for the clock plate and should not stand proud of the plates or be sunk into the plates.
Properly installed bushings will return gears to their proper alignment and will provide the optimal bearing surface for the pivot.  Carefully and accurately installed bushings will enhance the performance of the clock and result in increased value of the clock.