Watchmaking Screw Polishing Frog

This tool is used in horology to polish the heads of damaged screws, this model is inspired by brass version of the tool, but modified to be 3D printable.

The tool comes in two parts, the main body (Frog) and the bar which traps the screw to be polished. I have used M3 bolts throughout (see parts list below) and reinforced the areas under the bolt heads with a standard M3 washers. The slots in the top and back are to insert the 'trapped' M3 nuts (point down) - see x-ray picture. 

I used M3 wing nuts as locking nuts to prevent the bolts (legs?) backing off during use, I also included a cutout in the top to insert a bullseye level (10mm x 6mm) which hasn't arrived from Amazon yet, and so is absent from my pictures.
 

Parts list:

• 2 x 40mm M3 Stainless Steel 304 Hex Socket Head Cap Screws Bolts
• 4 x M3 Stainless Steel 304 washers
• 1 x Mini Spirit Level Bullseye (10mm OD x 6mm)
• 2 x Wing Nuts M3 A2 Stainless Steel Butterfly DIN 315
• 4 x Hexagon flat nuts A2 Stainless Steel M3
• 2 x 30 mm Fully Threaded Allen Key Hex Socket Cap Screws Bolts M3 High Tensile
   

3D printing settings:
 

• Material is PLA+, just what I had on the printer at the time, could also work with PETG etc.
• Fill is 75% gyroid, setting is high to ensure rigidity of the tool during use
• 1.6mm wall thickness, setting is high to reduce wear on faces which interact with metal parts.

Here is the YouTube video where I got the inspiration for this tool and the original brass tool design which I used to inspire my 3D tool.