The Chadwick Folding Bass is one of the most innovative upright bass designs ever created. Invented by Nashville bassist Charlie Chadwick, it was developed to solve the challenge of traveling with a full-size upright bass. Its unique folding neck allows the instrument to be transported much more easily while preserving the feel and sound of a traditional bass. Although relatively few were built, the Chadwick Folding Bass remains one of the most creative solutions ever developed for traveling musicians. This bass came into my shop because the bridge height was too high and needed to be lowered. Since the bridge was already fitted with handmade adjuster wheels that threaded directly into the bridge feet, the modification required careful planning to preserve the existing hardware. The wheels measured approximately 9 mm thick, so I first established a series of reference lines exactly parallel to the bridge feet. After drilling the adjuster holes slightly deeper, approximately 7 mm of material was removed from the bridge, allowing the wheel assemblies to fit properly while maintaining adequate wood thickness. The final fitting was checked with a grease pencil to ensure the adjuster wheels seated against a perfectly flat surface. The following photographs document each step of the process. - Determine the Amount to Remove – Decide how much the bridge needs to be lowered before beginning the modification.
- Measure the Adjuster Wheels – In this case, the handmade adjuster wheels were approximately 9 mm thick.
- Locate the Threaded Sections – The adjuster threads are installed directly into the bridge feet.
- Mark the Cutting Height – Measure 9 mm upward from each of the four straight facets of the bridge feet.
- Connect the Reference Points – Draw lines connecting the measured points across the bridge.
- Transfer the Lines to the Sides – Extend the ends of those lines onto the sides of the bridge and connect the corresponding points.
- Confirm the Lines Are Parallel – The completed reference lines should be straight and exactly parallel to the bottom surfaces of the bridge feet.
- Deepen the Adjuster Holes – Drill the existing holes slightly deeper so the adjuster wheel assemblies will fit after the bridge is shortened.
- Remove the Excess Wood – Grind away the marked section, leaving approximately 2 mm of the original 9 mm measurement. This shortens the bridge by about 7 mm.
- Check the Contact Surface – Coat the side of an adjuster wheel with grease pencil and press it against the newly prepared surface.
- Flatten the Surface – Use the transferred grease-pencil marks to identify high spots and continue fitting until the surface is uniformly flat.
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While researching this instrument, I came across an excellent five-part interview with Charlie Chadwick at Puremusic.com. In it, Charlie explains how years of frustration with airline travel led him to develop the folding bass, discusses the early prototypes, the engineering challenges, audience reactions when they first saw the bass fold in half, and how a project intended simply to solve his own travel problems grew into a revolutionary instrument. If you have enjoyed seeing the repair of this unique bass, I think you'll also enjoy reading Charlie's story. I've included a few of the photographs and engineering drawings from the article below as a preview, but the complete interview is well worth reading. Chadwick Interview 0cc6folding | 0cc4foldb | 0cc4folda | 0cc3post | | |
During this repair I wanted to better understand how the Chadwick Folding Bass was designed and assembled. Since the original Chadwick website is no longer online, I searched the Internet Archive's Wayback Machine, where much of the site has fortunately been preserved. The following photographs were selected because they document design and construction details that are difficult to see on an assembled instrument. I've also included links to several archived pages that are still functional for anyone interested in learning more. Archived Pages internal-storage-CFB-16 | fingerboard-fitting-CFB-3 | open-door-DSC2046 | open-closeup-DSC2038 | store-fingerboard-DSC2094-2 | store-tailpiece-DSC2047 |
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