Horological Meandering

rdenney
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Anatomy of a cheap winder...

I own several of the Brookstone winders with the angled fronts. I bought them used on eBay, along with one new one.

They use a Mabuchi DC motor, which is a decent Japanese motor. The problem with the motor is it has a high rotation speed, so it has to be geared down—a lot. The first gearing comes with the belt—a small spindle pulley on the motor and a large one on the gear reduction unit. The belt is a square belt used in audio equipment (for moving heads and trays—not for turning cassettes or CDs), and is not easy to source. And the break frequently—winder service has a much higher duty cycle than opening CD drawers on CD players.

And the gear reduction unit is rattly, so they won’t be silent.

But the DC motor draws minimal current and is easily switched. The winder times the rotations using a simple digital divider circuit that is programmable for frequency and direction of rotation. The wind is completed when tab on the pillow holder breaks the beam of an optical detector. If the belt slips or breaks mid-rotation, the motor will continue to run ad infinitum.

I’ve replaced the belts on mine a couple of times and need to do it again.

There’s a reason Orbitas have the reputation they do, and cost what they cost. But even though the belts are hard to source and replacing them a bother, I can buy a lot of belts for the price of 18 Orbita winder slots. I just can’t bring myself to pay that much to do something I probably shouldn’t be doing anyway.

Of course, having that many winder slots is itself insanity. But then watch collectors struggle to defend their sanity at the best of times.




The better of the Brookstone winders. Not my pic. One wonders at the need to wind a quartz chronograph, but there it is.



Square belt—an SBM-4.65 (Square Belt Medium, 4.65 inches in length).







What happens to the belts after a year or two of service.



The winder tray removed and flipped. The motor is at the bottom of each position, and the gear unit above it. Simple design, but the belts are the weak link.

—Rick