Post by CTGull on Apr 6, 2020 8:05:54 GMT -5
The purpose of the Neck Clamping Jig is to check the action, neck projection, and neck centering to the body with string tension while doing a neck reset, AND to clamp the neck to the guitar (and allowing you to verify its position) when gluing it back on.
The hardest, and most dangerous, part of a Yamaha FG neck reset is getting the neck off. It’s mostly physical, the 40-50 year old glue doesn’t want to let go. Not far behind is sanding the heel to get the correct neck angle. This is half physical and half mental. You can calculate all the numbers you want, but you don’t know how a neck is going to react with string tension after changing the neck angle. Some will bend more than others. Checking the neck projection will only get you close.
Putting strings on the guitar and checking the action with string tension is the best way. But, how can you string up a guitar when the neck isn’t attached? I made this jig to support the guitar and clamp the heel to the body. Then you can check the actual action under a real load. The only possible problem is over clamping which could possibly distort the body, throwing off the numbers very slightly.
I designed and built it out of stuff I already had. 2x2, 2x4, plywood, cork, open cell foam, drywall screws and a Harbor Freight screw clamp. I put cork on every surface that touches the guitar. There’s a clearance slot in the end block for the guitar end pin, which also helps visually center the guitar in the jig. The moveable clamp block is made of 7 pieces, the lower part locating it on the rail, the upper part locating and clamping the guitar heel (with cork on the surfaces that contact the heel), and a small piece of plywood and open cell foam to support the guitar body. Otherwise, pushing on the guitar can cause a gap between the fretboard extension and the guitar top, throwing off your measurements. And I cut off a Harbor Freight screw clamp, which is located in a slot in the rail and retained by 2 screws, to provide the force required to hold the heel against the guitar. The clamp block is also retained to the rail by a screw that rides in a slot. I added this recently because somehow the original clamp block was lost.
Assemble the neck to the guitar body, put them in the jig, and tighten the clamp a bit more than snug. I then use another Harbor Freight screw clamp at the 15th fret to hold the fretboard down on the guitar.
Install the 4 outer strings on both sides, tuned 2 steps down from normal. This will help the strings last much longer before breaking. Then remove the clamp at the 15th fret and install the 2 middle strings, tuned 2 steps down.
Occasionally check for a gap at the heel. Use just enough clamping force to hold the heel to the guitar body. Over clamping can distort the guitar body, possibly throwing off the numbers. Use a flashlight to be sure there is no gap at the heel or between the fretboard and guitar top. This is VERY important! Any gap will affect the measurements.
When gluing the neck back on the guitar, it is very important to clamp the heel to the guitar because hide glue will cause the joint to swell slightly. Without clamping there will be a gap at the heel, causing the action to be higher than expected. Clamping the guitar in the neck jig will help prevent that. It’s possible to clamp the neck and have a minor shift in position that you won’t notice until after the glue is dried. Installing the strings, while in the neck jig, will provide visual proof that the neck is in the same position as when you were checking the numbers.
A PDF drawing will be available soon.
The hardest, and most dangerous, part of a Yamaha FG neck reset is getting the neck off. It’s mostly physical, the 40-50 year old glue doesn’t want to let go. Not far behind is sanding the heel to get the correct neck angle. This is half physical and half mental. You can calculate all the numbers you want, but you don’t know how a neck is going to react with string tension after changing the neck angle. Some will bend more than others. Checking the neck projection will only get you close.
Putting strings on the guitar and checking the action with string tension is the best way. But, how can you string up a guitar when the neck isn’t attached? I made this jig to support the guitar and clamp the heel to the body. Then you can check the actual action under a real load. The only possible problem is over clamping which could possibly distort the body, throwing off the numbers very slightly.
I designed and built it out of stuff I already had. 2x2, 2x4, plywood, cork, open cell foam, drywall screws and a Harbor Freight screw clamp. I put cork on every surface that touches the guitar. There’s a clearance slot in the end block for the guitar end pin, which also helps visually center the guitar in the jig. The moveable clamp block is made of 7 pieces, the lower part locating it on the rail, the upper part locating and clamping the guitar heel (with cork on the surfaces that contact the heel), and a small piece of plywood and open cell foam to support the guitar body. Otherwise, pushing on the guitar can cause a gap between the fretboard extension and the guitar top, throwing off your measurements. And I cut off a Harbor Freight screw clamp, which is located in a slot in the rail and retained by 2 screws, to provide the force required to hold the heel against the guitar. The clamp block is also retained to the rail by a screw that rides in a slot. I added this recently because somehow the original clamp block was lost.
Assemble the neck to the guitar body, put them in the jig, and tighten the clamp a bit more than snug. I then use another Harbor Freight screw clamp at the 15th fret to hold the fretboard down on the guitar.
Install the 4 outer strings on both sides, tuned 2 steps down from normal. This will help the strings last much longer before breaking. Then remove the clamp at the 15th fret and install the 2 middle strings, tuned 2 steps down.
Occasionally check for a gap at the heel. Use just enough clamping force to hold the heel to the guitar body. Over clamping can distort the guitar body, possibly throwing off the numbers. Use a flashlight to be sure there is no gap at the heel or between the fretboard and guitar top. This is VERY important! Any gap will affect the measurements.
When gluing the neck back on the guitar, it is very important to clamp the heel to the guitar because hide glue will cause the joint to swell slightly. Without clamping there will be a gap at the heel, causing the action to be higher than expected. Clamping the guitar in the neck jig will help prevent that. It’s possible to clamp the neck and have a minor shift in position that you won’t notice until after the glue is dried. Installing the strings, while in the neck jig, will provide visual proof that the neck is in the same position as when you were checking the numbers.
A PDF drawing will be available soon.