Gruen Bumper

Gruen Diamond Dial cal 460

Gruen Diamond Dial cal 460

Here’s one I picked up for a daily wear watch that’s on the bench along with about a half dozen others right now. It’s a cal 460ss bumper which are a very easy movement to work on and the cross hair dial and diamond shape indices are a nice combination. The dial has received a dip in tarnish remover to take off the heavy patina and what’s left is flaking  lacquer to be dealt with later. there’s also a bit of rust on one bridge screw but it’s localized as far as I can tell so it shouldn’t be a problem. Updates to come.

Gruen Diamond Dial cal 460

Gruen Diamond Dial cal 460 with crumbs.

Bezel with new reflector crystal and case polished

Bezel with new reflector crystal and case polished

Re-cased after first cleaning

Re-cased after first cleaning

Dealing with the rust on the hands is the biggest issue in this case since any significant removal of the metal will result in plating loss. New hands may have to be sourced to finish it off. What’s left is a simple overhaul of the movement which is in very good condition. The bracelet is in good enough condition to keep with the watch., so it’s on the wrist and being wear tested.

1947 Gruen (bumper) Automatic

1947 Gruen (bumper) Automatic

Case and crystal refinished and waiting for hands and dial work
(restoration only)

1947 Gruen cal 460

1947 Gruen 460 Automatic (photo retouched dial)

1947 Gruen cal 460

Uncased and ready for cleaning

Gruen bumper Case

Gruen bumper Case before refinish

Gruen bumper Case

Gruen bumper Case during refinish

The tough part about scratch removal is retaining the bevels and not over polishing. Take your time and go slowly is the trick, and in my case a good pair of 2.5x reading glasses along with the 10x loupe. It’s still not perfect but as far as I’m willing to go to preserve the shape.  The best way I know of maintaining the flat on a case surface is to use sanding sticks, not loose sheets. Unless you’re laying the sandpaper flat and moving the watch on an even plane you will end up rounding corners. Using few strokes and inspecting often will pay off though it may take longer to get the work done.

Gruen 460 Dial

Gruen 460 Dial

Gruen 460 bumper movement

Gruen 460 automatic movement

There are some amateur watchmaker marks on the movement but it’s clean and running smoothly. It will be taken down, cleaned and oiled when the case and dial are finished.