Clock plate “fish scale” polish?

Joe Somebody

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Jan 29, 2020
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I saw a picture on the forum of a clock movement that someone had polished with a fish scale finish. It showed a couple round tools that had maybe had a pad at the end that were used to create the pattern.

I have searched for a while and now I turn to you good people for help!
Keep me from going over the edge...lol
 

Joe Somebody

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Thank you Simon!
I’m thinking of trying this on my father in laws old kitchen clock and putting a glass dial on it so you can see the works.
The old dial is rough, as is the case.
Maybe not original, but I think he would have liked it.
 

Bruce Alexander

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Hello Joe,

Welcome to the NAWCC's Message Board.

It's interesting that you describe the Herschede pattern as "Fish Scale". I thought so too.

As I mentioned, Steven Conover details the method in his book.

You basically create a Jig. It's a large indexed working table that securely fastens to your Drill Press Table.
You have a sub-plate which holds the movement's plate and slides on the index table.
The "X" Axis spacing is determined by index and reference lines on the index table and sub-plate.
The "Y" Axis spacing is determined by the addition or removal of wood strips at the top of the index table. These strips determine the Y-Axis position of the sub-plate as it slides against them.

The Damascene "circle" is created by a tool (steel, brass, aluminum or even wood) formed to hold leather lap pads in the Drill Press Chuck. As suggested by Conover I used Valve Grinding Compound on the Lap Pad.

Herschede also applied their Fish Scale pattern to many of their mantel clock movement plates although I imagine that the dimensions were smaller.

It's really pretty easy once you have all the materials assembled. Some Damascene Patterns are intricately carved works of art.

The process may take some time and I would suggest that you be careful not to overheat your Drill Press Motor. I placed a Fan next to mine which kept the motor relatively cool to the touch throughout the process. You can also just take periodic breaks to allow things to cool down. If you're working with small plates, it may not be much of a concern.

If you have questions, please send a PM (or start a "Conversation") and I'll try to help.

Good luck with your project.

Regards,

Bruce
 

shutterbug

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That finish is usually factory applied. If it doesn't have it now, don't attempt it unless you have the tools mentioned above. Just shine up the movement and apply shellac to keep it bright. Don't get any in the pivots. I once did what you are proposing. Stenciled numbers on the glass and left the movement visible. At the time I was selling clocks in an antique store, and someone liked it and bought it.
 

Joe Somebody

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Too bad my youngest son packed up his machine tools when he moved, that pattern would be easy to set up on a cnc vertical mill.
I saw an index table for sale on amazon, or maybe harbor freight, I'm sure the runout is horrible, but could be shimmed in and used on a drill press.
Well, looks like another for the project list! Thanks for all your input Gents!
 

Willie X

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I think you could easily do this with a simple set up of: a piece of plywood attached to the drill press table, a moveable straightedge, with a stop on the straight edge. Just measure the increments horizontal and vertical as you go. You would need to make sure the pattern was centered on both axis.

Please let us see what you come up with.

Willie X
 

Bruce Alexander

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Joe,

I'm sure the runout is horrible
Runout isn't that critical for this purpose and I'm not so sure that a cnc vertical mill would be ideal either although I'm sure you could come up with very elaborate patterns. :coolsign:

The lap pad requires a lot of cleaning and maintenance during the process. This pattern starts over the edge of a plate corner and ends over the opposite corner. Depending upon the dimensions of your plate and equipment, you might have to pattern half of the plate and flip it to work the other half.

Have fun.
 

Willie X

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You would have to go row by row, starting at the bottom or top with a fraction of a circle. Run-out would not be an issue. Placement could be + or - about 1/2 mm with no problemo.

Practice would be both fun and necessary.

Willie X
 

Bruce Alexander

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Yeah, practice on some scrap brass plate is a good idea although the pattern is very shallow and the plate can be wiped clean with vigorous application of a Scotch-Brite Pad. Scratches are very noticeable too so you'll definitely want to put a couple of coats of Lacquer over the pattern once your through with it...keeping it out of the pivot holes (and oil sinks ideally).
 

Joe Somebody

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You guys are the best! Some fantastic ideas, sounds like I have some sperimentin' to do.

I think you could grind the head off an allen bolt to make a mandrel or even take the hex off a regular bolt. Maybe a fine scotch brite pad would do vs. leather? Sounds like some fun when the weather warms up a bit, the drill press is in the garage so no heat.
This will give me time to assemble some parts.
 

Bruce Alexander

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Your dimensions will determine what tooling you need of course.

The pad needs to be fully supported and durable otherwise you'll spend a lot of time replacing it and the circles outer diameters won't be formed well.

The method I followed used contact cement to keep the pad in place. The tool is very easy to turn on a lathe. As I mentioned, when you're ready to begin your project, let me know if you have any questions about what worked for me.

Another consideration is working around post and/or riveted members on the plate. Briefly, you polish circles around the posts and then skip over the posts as necessary. The previously placed circles blend into your regular pattern and are not obviously out of sequence.

Regards,

Bruce
 

shutterbug

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Remember that the more distracting the movement is, the harder it will be to see the numbers. :)
 

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