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Home : Free Information : Neck relief, building and repair : Erlewine Neck Jig Instructions

Erlewine Neck Jig Instructions

Assembly and use

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i-5252 Updated 10/06


Parts list

The following items are included with your Neck Jig:

1 Jig board with threaded inserts
1 Jig beam assembly
3 Allen wood screws for beam/board assembly
1 Allen wrench
6 4" swivel-head levelers
6 Wing nuts for levelers
2 Wooden support slats
4 Cork lining material for support slats
4 Neck support rods
3 Orange caps for support rods
1 Black cap for support rod
4 Thumbscrews for support rods
2 Dial indicators
4 Hex nuts for dial indicators
1 Peghead jack
2 Ratchet hold-down straps
1 Peghead pull-down strap
1 Eyebolt for nut pull-down strap
1 Thumbnut for eyebolt
1 Instructions
1 Neck Jig instruction video

Tools required:
Adjustable wrench
Utility knife

Assembly instructions

Attach the Jig board to the beam with three allen-head woodscrews. An allen wrench is supplied.

The Jig board has ten threaded inserts. Install four swivel-head levelers extending upward as guitar body supports, and two extending downward at the front corners of the board to level the Jig on your workbench. Install the wing nuts to lock all the levelers in place.

Install the plastic caps on the neck support rods, and round the ends of the orange caps with sandpaper (the black cap for the peghead support rod needs no shaping). Install the neck support rods and the black thumbscrews that lock them in place in the beam.

Install the eyebolt in the Jig beam. The thumbnut threads onto the eyebolt below the beam. Install the peghead pull-down strap in the eyebolt.

Install the dial indicators on the beam's threaded bolts, using one nut below and one nut above the bracket on each dial indicator. The dials may need to be moved up or down on the bolts later when a guitar is jigged, to help position the dial indicator caps under the back of the guitar neck. (The bolts are set deep into the beam. Turn them out with locking pliers to gain additional height.)

Two wooden slats are supplied to give additional support to acoustic guitars. Self-adhesive cork is supplied for attaching to the slats, to help protect the guitar's finish.

Cut small pieces of the cork to fit the top and bottom surfaces of the peghead support jack.

Jigging a guitar: notes from Dan Erlewine

The Neck Jig lets you do your fretwork with the same forces that are present under string tension. It's not necessary to loosen the truss rod to straighten the neck for leveling the fingerboard or frets.

A guitar body is held firmly on the Neck Jig's adjustable height levelers, with nylon straps as clamps. The guitar neck remains free, as the Neck Jig and guitar are tilted toward 90 degrees into the "playing position." Here, with the strings tuned to pitch, the neck is adjusted (usually straight) for the type of fretwork you are about to do. The dial indicators touching the back of the neck are set to zero.

The Neck Jig is then returned to the horizontal working position. When the strings are removed, the neck "backbows" from the release of string tension and the pressure of the truss rod (if the neck has one). The peghead jack and the peghead "pull-down" are adjusted to recreate string tension. This forces the neck back into position until the dial indicators read zero again. Finally, the plastic-capped support rods are raised against the back of the neck for fret or fingerboard leveling.

A note about acoustic guitars: Before fastening an acoustic guitar (especially a flattop) into the Neck Jig, consider the guitar's construction. An acoustic guitar must be supported and clamped only in the areas of the strong joint between the sides, back and kerfing—not on the weak areas of the back!

Though some guitar models, Martin Dreadnoughts for example, will align safely on the levelers with support directly under the edge joint, others (such as the Gibson pictured) won't. Therefore, we recommend using the supplied wooden support slats to span the levelers. Adhesive-backed cork is supplied for padding the slats. Center the main hold-down strap over the guitar's waist and tighten it only enough to hold the body firmly. Do the same for the strap over the lower bout.

It's easier to level the frets, or the fretboard, when the guitar's nut is out of the way. If you're planning to replace the nut, remove it before you jig the guitar. Most refret jobs require a new nut.

1 Hold the guitar body over the Neck Jig and determine where the neck aligns lengthwise over the beam, and which posts will support it best.

2 If necessary, position the wooden supporting slats to span the front and rear levelers.

3 With levelers (and slats) installed, set the guitar body on them. Use a padded sandbag as temporary ballast to hold the guitar as you level it on the slats. Center the back of the neck over the support rods and the dial indicators. Adjust the body height with the levelers, so that the fingerboard is approximately level with the beam.

4 The guitar should be as close to the board and beam as possible, but be sure that the dial indicator plungers are engaged at least two dial-turns. The peghead should be over the peghead pull-down bolt in the beam, with sufficient clearance for the peghead jack. Remove the peghead jack and the pull-down strap after checking. The neck can be supported temporarily with the plastic-capped support rods, but when you tighten the body down, the support rods must not touch the neck.

5 The dial indicator support rods can be unthreaded from the beam for more height if necessary.

6 Place the hold-down strap across the guitar's waist, pass it under the beam, and thread it through the slotted hub of the ratchet. The ratchet opens toward you, with the strap connection at the top. The ratchet can be positioned above or below the Jig board; if below, be sure it doesn't jam on the table. Close the ratchet and snug the strap loosely.

7 Protect the guitar's finish with scraps of paper where the strap wraps the corners of the instrument. Some guitars will require two straps if they shift on the levelers.

8 Before tightening the straps, lower the neck support rods away from the neck. Tighten the straps gradually until the guitar body is snug on the levelers.

9 With the guitar tuned to pitch, move the Neck Jig onto its side in the playing position. Resting on a table, the Jig's front leg helps steady it. Adjust the neck for fret leveling or dressing: ideally, the truss rod should make the neck backbow when tightened and show relief when loosened. The neck should be straight for your fret work.

10 Set each dial to zero by turning the indicator's outer ring. The steel arrows slide around the perimeter and can be set to record a location. The thumbscrew locks the outer ring.

11 Return the Neck Jig to the horizontal working position and remove the guitar's strings. Adjust the peghead jack until it fits loosely between the beam and the end of the peghead. Install the peghead pull-down strap loosely.

12 The neck will backbow with the strings removed, and the dial settings will no longer be zeroed. In our case, the dial nearest the nut has compressed .031" and the dial nearest the body has compressed .008". These are typical readings.

13 Jack the peghead up a little until the frontmost dial reads zero again, and then tighten down the peghead strap until the rear dial is zeroed. Go back and forth between these adjustments, and squeeze the peghead pull-down strap to remove slack, until both dials remain at zero. (Note: You may not always get perfect zeros. If the peghead jack and pull-down strap don't zero the dials, use your straightedges, and your memory of what the fingerboard looked like in the playing position, and force the neck into the same configuration.)

14 When the neck is re-zeroed to your satisfaction, slide the plastic-capped support rods up against the back of the neck. The rods keep the neck from flexing while you level the frets or the fretboard.

15 In the photo I'm using a radius block to give a uniform radius to all the frets. After the guitar has been leveled for a fret-dress job, fretted and leveled for a refret job, or for whatever fretwork you are doing, you can remove it from the Jig and finish the details at your workbench. The guitar can remain in the Neck Jig throughout a fret job if you don't hammer the frets—the support rods could dent the back of the neck. The frets can be pressed or clamped in place with a variety of tools instead.

Body block idea for the Erlewine Neck Jig

An easy-to-make accessory for bolt-on necks

A body block is handy when you're working with bolt-on necks.
This wooden block holds a bolt-on guitar or bass neck, giving easy access to the truss rod nut. You can make adjustments to the neck while the guitar body is safely out of the way in its case. This gives lots of room to work on the high frets over the body without any chance of your file nicking the guitar. When you have the neck adjusted the way you like it, you're ready to bolt it back onto the body. Any 3"-thick hardwood or plywood will make a good body block.

Erlewine Neck Jig
Erlewine Neck Jig

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