Collector Guide How A Pocket Watch Crystal Maker is Keeping Vintage King Seiko Alive

Our resident vintage Seiko expert David Flett explains how White’s Crystals of San Francisco is serving the King Seiko restoration community.

The Problem That Needed a Solution

An inherent problem collecting and restoring vintage King Seiko these days is the lack of replacement glass crystals. In particular, a number of the King Seiko crystals are now so rare, one can pay more for an original factory crystal than one pays for the watch in need of it!

Many of these vintage King Seiko crystals came bonded to the watch rehaut which made the crystals very model-specific. The effect of this seems to be that there were historically fewer spares made available than the more generic crystals used across multiple Seiko models. For example, the last crystal I bought for a King Seiko 45-7001 cost $400 including the rehaut in 2021. This is a silver unit with the serial number 300V05GN, and I have not seen another for sale since (though gold rehauts are still available).

So, in short, original crystals for these King Seikos are both rare and expensive, and that’s a problem.

300V05GN with combination rehaut and crystal
300V05GN with crystal bonded to the rehaut

The Solution to the Problem

Step forward William White, a pocket watch crystal maker based out of his home in San Francisco, who has the solution. 

William started creating his own replacement crystals 20 years ago when repairing pocket watches professionally. In those 20 years, William has devised his own system and tools for shaping flat sheets of glass into the curved crystals required for vintage pocket watches. He creates around 3500 watch crystals annually and is recognized as the sole source of new glass for certain models.

Five years ago he was asked to make a replacement crystal for a King Seiko based on an original example. William found the original had a hint of curvature on the top with a little more curvature on the underside. He concluded that the proprietary Seiko ‘Hardlex’ was either cast in that shape or ground to create the two non-parallel curved sides.

In contrast, William starts with flat sheets of glass from companies in Germany, UK, Belgium and Switzerland and shapes the crystals with heat applied via digital kilns which allows the specific curvature to be applied. The resultant crystal sides will always remain parallel with William’s production method, unlike the Seiko original, but the results turn out to be very similar. I doubt anyone could notice the difference.

William White's replacement crystals
One of William White’s replacement crystals

Replacing the Glass in King Seikos

William can supply a direct replacement for the glass in in the original 300V05GN rehaut used for a number of King Seiko models, including the 45-700x models, for which no original glass seems to be available. In order to utilize his crystals the old glass needs to be removed from the old rehaut and the new glass glued in. It’s simpler than it sounds.

Removing the glass from the steel rehaut is as simple as boiling them for a few minutes. I tested a number of originals and 15 minutes was enough in each case. The boiling water softens the glue that Seiko used to attach the crystal to the rehaut, allowing the crystal to be pushed out from its steel ring. Once separated, the residual glue can be removed from the ring with some pegwood or a cocktail stick without damaging the rehaut. If the glue hardens back up before it’s all removed, a short dunk in the boiling water will soften it up again.

Removing the old crystal glue
Removing the old crystal glue
With the crystal removed, the old glue must also be carefully removed

With the crystal and old glue removed, fitting the new crystal is just as easy.

Seiko still makes the S-314 UV curing crystal glue used for the original (although there are other brands of glue that will also work). A UV curing glue allows the crystal to be carefully positioned without fear of the glue setting up prematurely. I definitely would not suggest a quick setting super glue for this purpose.

A small amount of glue needs to be laid down around the inside of the ring, using something like an oiler or a needle. All that is needed is a thin even film around the ring before pushing the crystal into the ring to compress the glue. If everything looks good then one hour under a UV lamp will harden and clarify the Seiko glue so it becomes essentially invisible.

Seiko's own crystal glue
Applying the crystal glue
Setting the glue with UV light
The new crystal needs to be secured with UV-cured crystal glue

Once fitted, the replacement crystal has a gentle curve to it. Probably a little more above and a little less below that the originals but to my naked eye they look extremely similar.

William allows purchasers to specify the height of the crystal before the bevel starts when ordering. I ordered a heigh of 1.2mm and that was too high. If you look carefully at the images, the bevel on the original is a little bigger than the replacement. Next time I order a 300V05GN replacement, I will specify a height of 0.9mm or even 0.7mm to get a closer approximation to the original.

There is also a small difference in color cast when compared directly – William’s glass is a little darker, maybe a touch more grey than the original but once fitted, the difference is not noticeable.

Replacement (left) versus original crystal (right)
original (left) versus replacement (right)
The bevel difference in the crystals is down to the author’s ordering error

While not exactly the same profile or color, William’s replacement crystals are very close… close enough that one cannot tell the difference once the crystals are installed in the watches. The fit in the rehaut is perfect, and although the old glass needs to be removed and the new crystal glued in, the process is extremely simple. If you or your watchmaker needs a replacement 300V05GN crystal for a King Seiko, William’s replacements provide a high-quality solution to the problem of finding original factory replacements.

William can be found on with username wcmfg_crystals.

For the record, Beyond the Dial has no affiliation with White’s Crystals. This article has been written with the sole purpose of informing the wider watch community of the availability of these crystals after the author purchased some crystals for restoration purposes.