Borg Instruments Clock

Fixing a vintage El Camino dashboard clock

With everything going on in the world today it’s probably not much of a surprise that I haven’t had the time I normally would to engage in my favored hobby. My family moved to a new home in April of this year which was a challenge due to the local pandemic response. I lost my workshop and have been relocated to the garage which gets pretty warm in the summer months. It’s also been the hottest year on record (again). Consequently I’ve avoided working on watches and clocks until it cools down a bit.

Earlier this year my father called me after disassembling the dashboard of his ’66 El Camino. He wanted to know if I could take a look at the clock which was not working. I agreed and and picked it up from him the following weekend.

Now since this was in the middle of packing things up for our move I took a lot of pictures but not many notes as I didn’t think I’d be blogging about this one. Today I have a little time on my hands and I came across the pictures so I thought I would toss them up.

The clock is a simple little thing (on the outside) as it’s just two hands and a painted dial. The back of the housing is stamped Borg Instruments Delavan Wis and has a single 12 volt electrical connection.

Borg Instruments dashboard clock
The clock removed from the El Camino’s dashboard
Rear view of the Borg dashboard clock
Rear view of the clock housing

The housing comes away by straightening the lip bent over the three tabs on the plate attached to the rear of the dial.

Close-up of tab connecting clock face to housing
The housing is bent over to tab to secure the clock

I really had no idea what to expect once I got this thing open but I still ended up surprised. Inside is an electrically actuated mechanical movement, the mechanical part much like that of a watch movement.

The movement is built up in layers like a cake. The top layer (that closest to the rear of the housing) has two contact points and a solenoid. The middle layer is the Going Train which is more or less identical to a watch movement. The bottom layer is the Dial Train or Motion Work which you’ll also find under the dial of a typical mechanical watch.

Side view of the Borg clock movement
The mechanism is revealed
Close-up view of the clock movement
Close-up view of the movement layers

A coil spring acts as the Mainspring for the movement although it only has about two minutes of energy stored in it. The spring is pulled taught by the solenoid when energized. As the seconds tick away the spring collapses bringing the contact points closer together, when they touch the solenoid is energized again and the cycle repeats.

Based on some preliminary research (thanks YouTube!) I expected the contact points or coil would be the failure point but discovered this was not the case.

Solenoid removed from the mechanism
The solenoid removed from the movement

The contacts were dirty but they would clean up fine with a bit of isopropyl alcohol- the real problem resided in the movement.

Top plate of the movement
Looking down at the Top Plate

The movement is a pin lever design with just two jewels; one for the top and another for the bottom pivots of the Balance Assembly. The lack of jewels in the movement coupled with the fact that the clock ran continuously and without service for so many years resulted in multiple bearings failing.

Unlike a watch movement, which changes position constantly, the gear train in a clock movement is perpendicular to the force of gravity. If not serviced regularly, gravity and friction will turn every round bearing into a teardrop shape, eventually causing the movement to fail. The solution is to ream out the old bearings and install new ones.

This would prove to be a fun project as it had a bit of lathe work; I commenced to breaking down the movement for cleaning.

Close-up of the clock movement
Close-up shot of the gear train and mainspring
Another close-up shot of the gear train
Close-up from another angle

The upper and lower bearings for the Mainspring Assembly seemed to get the worst of it but the Center Wheel and Third Wheel bearings were out of round as well. I believe I replaced five bearings in all.

Mainspring Assembly
The Mainspring Assembly with ratchet

There was excessive wear to the pivots of the Mainspring Assembly too. The pivots are made of steel and the bearings of brass but both suffered here.

Gears from the mainspring assembly
The pivots of the mainspring assembly look a little tired

The dial of the clock is connected to the watch movement by way of a intermediary steel plate. There are no dial screws like one would see in a Swiss watch; the dial secured to the plate by three tabs which are bent over.

Borg electric clock
the Hands and Setting Knob are removed before the dial comes off
Borg electric dashboard clock with dial removed
The dial is removed revealing a steel plate beneath

The Dial Train is a bit interesting. The gearing for setting the time is riveted to the plate underneath the dial as are gears which lead to the Regulator. In a way the clock is self regulating and here’s how it works: when the clock is running slow, you’ll need to adjust the time adding hours or minutes. Whenever you adjust the time the regulator is moved ever so slightly. If you consistently add minutes to the clock, the regulator is consistently adjusted to slow the movement. The theory is that the need to adjust the time will cease once the movement is properly regulated. Of course if your car battery is always going dead then the theory won’t pan out.

Borg electric dashboard clock movement
The Dial Train- note the gear for adjusting the Regulator (top right)
Dial train of Borg electric clock movement
Dial Train with Hour Wheel removed
Dial train removed from Borg movement
Down to the Bottom Plate

This movement was a little too large for the L&R Watch Cleaning Machine and so the parts were scrubbed by hand and dipped in the ultrasonic bath instead. I needed to re-bush several pivot holes in the plates so I turned new bearings on the lathe.

Clock bearing speared on broach
One of five bearings turned on the lathe

The movement has a pretty simple Balance Assembly. The Hairspring is secured to the bottom plate by a bit of shellac. Melting the shellac was little nerve-wracking. I found a soldering iron worked well to control the heat and flow of the shellac.

Balance Assembly
The Balance Assembly removed and cleaned
Balance Assembly reinstalled
The Balance Assembly is reinstalled and secured to the Bottom Plate

The entire Going Train is sandwiched between two plates. Thus lining up all the pivots can be a chore. The pillar construction of the movement made things a bit easier though as there was a lot of room to maneuver with my tweezers.

Borg movement reassembled
Dial side reassembled. One re-bushing is apparent
Borg movement reassembled
And here is the top side, before the electric bits are installed. A few more re-bushings can be seen

I assembled the movement and connected it to the car battery for testing. Twenty-four hours later the movement was running a couple minutes slow so I turned the regulator to speed it up. I couldn’t test this movement on my timegrapher so it’s going to take a bit of trial and error to dial it in just right but the fact that it’s ticking again is promising.

Borg electric dashboard clock
Reassembled and ready for installation

As far as my father is concerned it was a job well done. He’s had a rough year (haven’t we all) and hasn’t had a chance to stretch the legs of the El Camino. Once he’s accumulated some miles on it I’ll know whether the job was well and good or just another learning experience. Regardless, I did enjoy working on something a bit different and something engineered in the USA.

Author: JPMoeller

Amateur watchmaker and California resident

One thought on “Borg Instruments Clock”

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