The problem I have is that the gold medallion protrudes out of the case back so polishing on a flat surface wouldn't work. Does anyone know of a competent person who could either remove the medallion temporarily or, somehow remove the scratches with the medallion in place? I estimate the scratches to be between 100 and 200 microns deep, say 150.

 

Once the medallion is removed it is really hard to put it back in place like original.
You can try by using masking tape on it when buffing or just leave it the way it is.

 

The scratches will need more than a buffing to remove, they are quite deep. If the medallion wasn't in place I could tape down a sheet of emery paper to a very flat, hard surface (e.g. glass) and rub the case back until the scratches were gradually gone using different grades of grit in the emery paper and then finishing off in one direction only so as to get the satin finished look or perhaps polish to a mirror finish using emery and then metal polish. The medallion prevents me doing this.

 

Not so hard. Caseback is mounted on a lathe and the steel is polished leaving the medallion untouched.

Tom

 

Now you're talking .......where can I get this done? I was told by one watch restorer that a lathe tool would rip at the tool indentations on the case back??? He didn't advise it but I think it would be ok, who does this kinda work?

 

Once the caseback is spinning on the lathe, you'd use sandpaper to polish out the marks, not a lathe cutting tool. Maybe your local high school shop has a lathe you could borrow?

 

Just find a different watchmaker. Any time one spouts nonsense, you know it's time to seek elsewhere.

Tom

 

Not recommended. Just chucking it would likely deform the caseback so much it would never fit ever again.

A watchmaker's lathe is a small thing that fits on a bench, not something that weighs a thousand pounds.

Like I said, it can be done by a competent watchmaker.

Tom

 

Polishing can remove 150 micron scratches of course - I know everyone thinks of this as using fluffy wheel with little pressure but polishing can involve a number of different wheels and materials such as rubberized abrasives, hard felt wheels with aggressive compounds, stitched buffs with finer compounds, and then of course the unstitched muslin buff with colouring compound to give that final mirror shine.

But to reduce the risk of getting an uneven surface, using a lathe is the best way in this case I suspect. You can use a graver (HSS rather than carbide for an interrupted cut would be my advice) to take a skim cut off the back, or use abrasives to do the job, which would take a bit longer. It can be done on a large engine lathe if you can chuck the case back, but a smaller watchmaker's lathe or bench top engine lathe would be better. Of course to prevent damage and get clear access to the whole part you chuck on the inside of the case back, not the outside.

Similar to what I'm doing here on this case...



But are you sure you want to remove enough material to get rid of the gouges? I would personally consider getting the gouges laser welded first to bring the surface slightly above the existing surface of the case back, then doing the machining to clean it up.

Cheers, Al

 

Thanks Tom and Al for your replies. Al, you look as though you know what you're doing, would you take this on? I doubt that the scratches are more than 150 microns.