NON-PBG - LP Build Diary for DIY Guitars GLP-40BBK

[wazkelly]

How flat is the neck?

Sounds like you need to run a long straight edge the whole length of your fret board to see where things dip. A long metal ruler or even a spirit level should do the trick as if you are that low at the nut your problem is most likely elsewhere and my bet is on too much forward bow in the neck.

EDIT: Just re-checked some of your build thread and as yours is a bolt on neck maybe you are experiencing similar thing that happened on my DIY Guitars closing down sale Tele where the neck sat too high off the body by about 7mm and caused me no end of intonation, pitch and action dramas.

Ended up using a block of timber cut to size and gradually sanded down where the neck heel joins into the body. Handy if you have a similar axe as a reference point otherwise you are flying blind. Towards the end I even used the metal neck plate as the sanding block seeing it was pretty close to the right size for area being sanded. From memory I think 120 & 180 grits were used otherwise it takes forever.

[Alkay]

How flat is the neck?

Sounds like you need to run a long straight edge the whole length of your fret board to see where things dip. A long metal ruler or even a spirit level should do the trick as if you are that low at the nut your problem is most likely elsewhere and my bet is on too much forward bow in the neck.

It appears straight from the nut to the 12th fret with a metal ruler. The other longer ruler I have just sits on top of the bridge so I can can an absolute indication on the full length. I might be able to cut 20mm off it tomorrow or have a shop around for a spirit level that will fit the length of the fretboard.

I did have backbow, maybe I loosened the truss rod too much. I was following the intonation guide and was trying to close the gap at the 9th fret so a business card just fits.

[wazkelly]

Hey mate, before cutting things or spending any money maybe just remove the bridge and run the long rule all the way to see how things are. Even with the bridge in place you should still be able to place it at a slight diagonal angle for the whole length.

Another idea is to do the capo at 1st fret and with strings at proper pitch draw the low E down at 12th and again at last fret which should be 22nd on a LP. Check how much gap is under the string from each of those reference points back to the capo'd spot. If all of this reveals a dead flat deck the problem will be elsewhere.

[Alkay]

Hey mate, before cutting things or spending any money maybe just remove the bridge and run the long rule all the way to see how things are. Even with the bridge in place you should still be able to place it at a slight diagonal angle for the whole length.

Hi wazelly,

I used your first option above to check how straight the neck is with my 600mm metal ruler positioned in the center of the fret board:

- There are no gaps between frets 1 to 8.

- Fret 9 there is a tiny gap and this increases up to fret 22 where the gap was about 1.5mm high

I have researched this allot so please correct me if I am wrong:

- A rocking motion on the neck is caused by "back bow" and this IS currently what is going on with my neck.

- If I had the opposite, which I don't. But if I did there would be gaps between the straight edge and middle sections of the fretboard caused by "front bow".

Therefore to fix my back bow issue I need to do the following:

- Looking directly at the truss rod hex screw near the headstock, turn the truss rod to the right(clockwise) 1/4 of a turn.

- The gap between the straight edge and the 22nd fret should be decreased.

- Repeat this until there are no more gaps or rocking motion over the frets.

I hope I have explained that well enough and if I have anything wrong please let me know.

Cheers,

Alkay.

[Andy40]

I agree with Waz, Alkay. Capo on the 1st and depress at the 12th and check the height at the 9th. If you are going to do any further guitar building, I would get a notched straight edge.

[Alkay]

I agree with Waz, Alkay. Capo on the 1st and depress at the 12th and check the height at the 9th. If you are going to do any further guitar building, I would get a notched straight edge.

Thanks Waz and Andy. I'll give that a test tomorrow and let you know how I go.

Good advice on the notched straight edge. You save me asking that question

Cheers,

Alkay.

[Andy40]

Use mine all the time Alkay

[stan]

A straight edge across the frets tells you if the frets are level, not necessarily the neck - a notched straight edge will show if it's the neck.
A rocking motion can be caused by back bow or high or low frets, but yes sounds like you have back bow to a degree
You need to loosen the truss rod a tad ; from the nut looking towards the bridge turn the truss rod Anti clockwise by a small amount, this will loosen the rod a bit.
The rod has the most effect in the centre section of the neck, - give it a try and see how you go, go 1/4vturn at a time and you will be fine, even if you get it wrong, then just go back

[Alkay]

A straight edge across the frets tells you if the frets are level, not necessarily the neck - a notched straight edge will show if it's the neck.
A rocking motion can be caused by back bow or high or low frets, but yes sounds like you have back bow to a degree
You need to loosen the truss rod a tad ; from the nut looking towards the bridge turn the truss rod Anti clockwise by a small amount, this will loosen the rod a bit.
The rod has the most effect in the centre section of the neck, - give it a try and see how you go, go 1/4vturn at a time and you will be fine, even if you get it wrong, then just go back

Hi Stan,

Thanks for the reply, so I was wrong. Turning left reduces the amount of back bow.

Is a cheap notched straight edge on ebay($20-$25) suitable?

Is anyone on here using these or should I just pay for a decent one from stewmac's site for example?

It doesn't look like PBG sell a notched straight edge but I would at least like to buy locally in Australia if I can.

Cheers,

Alkay.

[stan]

Hi Stan,

Thanks for the reply, so I was wrong. Turning left reduces the amount of back bow.

Is a cheap notched straight edge on ebay($20-$25) suitable?

Is anyone on here using these or should I just pay for a decent one from stewmac's site for example?

It doesn't look like PBG sell a notched straight edge but I would at least like to buy locally in Australia if I can.

Cheers,

Alkay.

yes, correct.
turning clockwise tightens the truss rod, causing it to induce what you call back bow
anti clockwise loosens the rod - front bow
Pabs makes great notched straight edges - i have a couple in different scale lengths
Another super cheap option is to buy a steel ruler and notch out where the frets are, will work fine, but hit up Pabs, they are cheap and awesome