Accutron Spaceview Conversion
(for Accu-nerds only)
What they are and how to spot one: Page 2
Numbers Don't Lie:
For simplicity I'll describe the details using specific dimensions of US models only, but the same basic points apply to Swiss models. There are only two Chapter Rings used in the most commonly found US models. The thickness and outside diameters by part number are:
R523 = 0.030 inches thick (0.75mm) x 1.277 inches diameter (32.43mm) - Stainless Steel model only.
R524 = 0.022 inches thick (0.55mm) x 1.217 inches diameter (30.9mm) - Gold-Filled or Gold-Plated model only
The inside diameter or movement cavity of all 214 bezels is 1.135 inches (28.8mm)
Thickness of the shoulder at the bottom of the crystal cavity and/or the top of the movement cavity is 0.018 inches (0.45mm) (shown between red arrows in the photo below).
All Chapter Ring Bezels are specifically designed to accept the ring under the crystal. All Chapter Ring Crystals are the press-in type with either a white (W) or yellow (Y) metal reinforcing ring on the inside rim. These are called Armored Crystals. The tight press fit of these crystals holds the chapter ring securely in place. They are known as Armored White or Armored Yellow Spaceview Crystals and designated by the following part numbers:
#1270AWS -1.285 inches (32.7mm) (fork at 8 or 12 o'clock)
#1271AYS - 1.228 inches (31.1mm) (fork at 8 or 12 o'clock)
Two new versions of existing dial models were designed in order to accommodate a chapter ring. The chapter ring is seated on a thin shoulder at the bottom of the crystal cavity and the movement is installed up against the opposite side of that same shoulder. The two new models were given a deeper crystal cavity by moving the shoulder into the space that would normally be occupied by a dial. That modification also eliminated the need for a dial spacer ring. The photos at right show the shoulder and the underside of the chapter ring after the movement has been removed.
Imitation Chapter Ring Spaceviews:
They do turn up occasionally, but they always look phony. None of the original factory chapter rings in their original form will fit inside the movement cavity of a 214 bezel. There are a number of 214 model bezels that will accept a 30.9mm diameter or larger crystal so an R524 chapter ring will fit into the crystal cavity, but that would not leave enough wall area for a press fit crystal to grab onto. An ordinary 214 crystal cavity can't be made deep enough to accept the added thickness of a chapter ring because the thin shoulder mentioned above is already at the minimum required thickness of 0.018" and the required additional space for the thinner of the two rings is 0.022".
Look for a crystal with too much of its side wall sticking out of the bezel and for evidence that the crystal has been glued to the bezel.
How to spot a counterfeit Chapter Ring Spaceview
The answer is mostly no and a little bit yes.
The Chapter Ring is real, but it's been machined to the dimensions of a Dial Spacer Ring so that it can be installed in any ordinary dial model. See above.
Above Left: Dial Spacer - Center: Machined Chapter Ring - Right: Factory Chapter Ring
© 2002 by Martin Marcus. All rights reserved. These pages may not be copied without written consent.