Homemade 3D Carving Duplicator

bridge duplicator

[Frank] is a guitar builder and has to make a quantity of acoustic guitar bridges that wouldn’t make sense to do manually by hand each time. He wanted a way of duplicating bridges quickly and precisely but he didn’t want to go to a CNC machine. Instead, he build a 3D duplicating machine.

The machine has 3 perpendicular axes, just like a milling machine. Mounted to the Z Axis is an air powered spindle that can reach 40,000 RPM. All 3 axes are moved by the operators hands. Normally, free-hand cutting something like this would be very difficult. [Frank’s] solved this in his machine by using a stylus that is offset from the cutting bit. The stylus is the same effective length and diameter of the cutting bit and is guided over a finished bridge pattern. While the stylus is tracing the pattern, the spindle and bit are removing material from a bridge blank. The stylus is continually moved over the entire pattern bridge until the spindle is finished carving out a new bridge out of the blank.

To aid in lifting the heavy Z Axis and spindle, [Frank] added a counter balance to make tracing the pattern extremely easy. Once the new bridge is carved, it only requires minor sanding to remove the tool marks before being installed on a guitar! [Frank] admits his linear bearings and rails are very rigid but also very expensive. If you’re interested in a less-expensive 3D duplicator, check out this project.

8 thoughts on “Homemade 3D Carving Duplicator

    1. For the stuff he does, repairing guitars, that is all he need if he needs to duplicate a broken part. No programming needed, just copy. Even a part made by cnc with a 3d profile will need some cleanup.

      1. What would be nice, although require a new machine, would be the ability to record the “scan” he makes of the original part and remake it again and again, CNC, sure but with a unique method of programming.

  1. That’s essentially the exact method NASA used to hand carve blocks of silica foam for replacement space shuttle tiles. I wonder what will become of the huge room full of rows of shelves with all the full scale 3D master models of the tiles for all the shuttles? Then there are the card catalogs, one that tells where in the pattern room the patterns are, and one with the stencils for the numbers to paint on the finished tiles.

    NASA could make a fortune selling those as sets, each tile pattern with its location card and number stencil. Put them in acrylic boxes and start auctioning them off.

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