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Epiphone Triumph Truss Rod Replacement

10/14/2014

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1. An Epiphone Triumph.  This very cool arch top guitar was built in 1950.  It’s a players guitar with multiple visible repairs and lots of wear and tear.  The guitar is in the shop for a few repairs including a neck reset and refret. 2. Fretboard Separation.  The fretboard is coming away from the neck near the body.  The problem is the antiquated adjustable truss rod that Epiphone used.  The “thrust rod” is literally pushing the neck apart.  I’ll disassemble the neck and replace the truss rod with a more stable non adjustable square tube.
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3. Removing the Neck with steam.  I drilled a 3/32″ hole diagonally through the heel and tenon in order to get steam into the gap between the end grain of the neck and the neck block.  The steam softens the glue in the dovetail joint as I pull the neck free. 4. Removing the Fretboard.  With the neck removed from the body, I’m heating up a few inches of the fretboard at a time with a heat lamp.  A thinned butter knife severs the old hide glue joint.
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5. The Truss Rod on this guitar is a long screw that’s threaded through a rectangular nut by the heel.  As the screw is tightened it pushes against a steel block near the nut which reduces the relief in the neck.  In order to work, this system requires the truss rod assembly to sit as high in the neck as  possible. 6. The Nut.  The truss rod and nut are inlaid about half way into the neck.  Conversely, a conventional Gibson style truss rod is buried deep within the neck and is covered by a hardwood spline which is hidden beneath the fretboard.
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7. Truss Rod Channel.  Because the rod sits about halfway into the neck, there is a corresponding channel in the fretboard. 8. The Steel Block.  This is the fixed block that the rod pushes against by the nut.  I’ll remove this old truss rod assembly and install a more stable square steel tube.  The neck will no longer be adjustable but this is a cost effective and minimally intrusive approach.
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9. A Square Steel Tube.  This is a stiffer, modern version of the square tube used by Martin in the 1970’s.  The original truss rod channel is too narrow and too shallow to accommodate the new rod. 10. A Quick Bend in the truss rod will help give the neck a slight back bow and more resistance to string tension.
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11. Rosewood Splinter broke of off the fretboard during disassembly.  I’ll remove it from the neck with a razor blade and glue it back onto the bottom of the fretboard. 12. Truss Rod Routing Jig.  I’ll use a straight downcut bit that’s the same width as the square tube to cut the new channel.  Two bearings on the shank of the bit are guided by the slot in the plywood.  The guide is held to the neck with wood screws.
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13. Setting the Depth of cut of the router bit.  I want the channel about .010″ deeper than the thickness of the truss rod. 14. Routing the Channel.  I’ll make 2 or 3 passes, each progressively deeper, with the router adjusted to it’s slowest speed setting.
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15. Coming Up Short.  The channel isn’t quite long enough to accommodate the rod.  Plus, I want the rod to end a little closer to the string-nut.  I’ve scribed the neck around the end of the truss rod with a marking knife. 16. A Sharp Mortise Chisel chops out the waste at the end of the channel.  I’m alternating between downward and inward cuts with the neck resting on a sandbag.
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17.  Almost Done.  The channel is almost ready to accept the new truss rod. 18.  Fine-Tuning the channel.  Spot planing with a small router plane knocks down any high spots in the channel’s floor.  I’ll hand sand the channel a shade thinner for a snug fit with 80 grit sandpaper.
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19. Thin Super Glue wicks down and around the new truss rod.  While the glue cures, I’ll clamp the square tube down at the center of the neck. 20.  Scraping the Neck gets rid of the old hide glue and any super glue squeeze out.
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21. Fretboard Filler Strip.  I’m hand planing a strip of rosewood to fill the old truss rod channel on the under side of the fretboard. 22. Gluing the Filler Strip.  A piece of carbon fiber is a good clamping caul for the filer strip.  I’m using franklin’s original titebond for the filler strip.
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23. Preparing the Fretboard for gluing.  After 24 hours I planed the filler strip flush.  A scraper and sandpaper true the bottom of the fretboard for gluing. 24. Sanding on the large, flat granite slab reveals any high spots that I will clean up with the scraper.
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25. Locator Pins.  I’m using the original factory locator pin-holes to align the fretboard during gluing. 26. Hot Hide Glue is my glue of choice for the fretboard. I’ll leave the neck clamped for 24 hours then scuff sand the finish around the binding and overspray the neck with a couple of coats of lacquer.  The function over form touchup work won’t be invisible but the finish will be stable and won’t feel bumpy or sharp.
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27. A Refret and neck reset complete the repair work. 28. A Vintage Epiphone.
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29. The Finish held up okay and didn’t require much attention because the neck and fretboard realigned very well due to the use of the old locator pin holes.