A Calculated Risk - Project Restoration/Build - 72 Seiko 6138-7000 Slide Rule Chronograph

I am excited to share this particular restoration with you as you do not often see these Seiko 6138-7000 Slide Rule chronographs and this is the first one I have actually worked on and held in the metal. Thanks for forum member Chris for sending this one into me for restoration and service. This particular watch showed up on my doorstep looking worse for wear and missing its plastic indicator ring. Chris was kind enough to source and aftermarket one for use on this project. I want to thank Seikopsycho2 (Tom) for helping me source the necessary gaskets for this build with the exception of the outer rotating bezel o-ring gasket which I had to measure up and source generically from Esslinger. I will provide dimensions for that in the notes below for others to reference if needed.

This watch is quite unique in its case construction looking similar in profile and dimension to the more well know 6138-0011 UFO Yachtsman chronograph. However, what makes the 7000 unique is the construction of the upper bezel slide rule which consists of a fixed inner bezel with insert machined to the case and the outer rotating bezel that snaps down onto the inner bezel and contains a rubber o-ring measuring ID ~35.5mm by 0.70mm thickness based on my caliper measurements of the original gasket which in this instance was hard as a rock. The Slide Rule chronographs also utilize a plastic rotating ring that affixes to the inner bezel between the bezel inner flange and acrylic crystal. The crystal while a bit dirty and somewhat scratched could be salvaged with some wet sanding and polishing; one thing I enjoy about acrylic crystals. Very pleased with the end results of the case work.

This particular watch, while showing excessive dirt and grime in the bezel and underneath the bezel had a lot of potential. The bezel inserts were unfaded with no loss of text or major scratches. The dial and hands were flawless. Upon opening the case back, the movement was shiny and bright with no service marks in the case back. The only cosmetic issue I found was where someone had used an oversized screwdriver to tighten one of the winding bridge screws and left a bit of a mark in the bridge around the machined screw hole. I also found a slightly bent pusher shaft on one of the pushers which I was able to straighten. New pusher seals solved any sort of stickiness occurring with the pushers.

The movement cleaned up like new and with service ran strong right out the gate with amplitudes in the upper 230s and low 240s. Timing and beat error were both good for this particular watch with timing +3 to +5 sec per day.

Please enjoy the pics of this unique vintage Seiko. It was a pleasure to work on and turned out beautiful. I hope Chris, the owner, will be happy to put this one on wrist.

Before:




Dial Date Code and Case Back Serial # (Dial original to this watch)

Case Cleaned and Assembled




Movement Service







Timing and Regulaton