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Happy Jack's Mike Lull Necks


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Some of you might have seen @Happy Jack 's thread relating to his lovely Mike Lull P5.


And very lovely it is!



The result of the discussions on that thread is that (and many thanks to the folks who put my name forward) I spent a pleasant and interesting hour earlier in the week with Jack and @Silvia Bluejay at a pub somewhere in Oxfordshire.


It's going to be an interesting project - one that I will slot into the lull periods (sorry - couldn't resist) of the ebony guitar build that I snuck into the Build Diaries.  There are two necks that I will be working on:


The present fretted neck

- The truss rod is maxed out and the neck seems to have a permanent set that the rod can only just control...for now.  This probably means taking the fretboard off (it's a glued on fretboard), planing the top of the neck, probably replacing the trussrod and probably refretting if the board removal has disturbed them or if they need removing to get the board off in the first place.

- While we're at it, Jack would ideally like 2-3mm off the width of the neck, presently 38mm.

- There are also some retro-fit epoxy dots that want removing and replacing with Luminlay dots




- Also, Jack's preference is silky smooth wood rather than the present lacquer on the playing surface (we'll make sure the headstock and logo aren't affected


We talked about the risks of fretboard removal but Jack's view is that, if it isn't unusable at the moment, it won't be long before it becomes so.


Then Jack came up with a corker of an idea. 


As we don't know how deep those epoxy dots are, but if they are, say 2mm - 3mm deep...could we take the whole 3mm off the bass side and that would solve the challenge of filling the holes?  One of those times when is goes quiet in the snug...and, after a few moments of quiet contemplation...yes...it's worth a try!  We talked about the fact that the top dots won't line up -  but actually, they don't anyway.


So that's the plan.


A new and easily interchangeable fretless neck


So I will also be building a new neck - again narrower than the present P by up to 3mm.  Probably maple neck, unlined ebony fretboard, luminlay side dots at the fret positions.



So first step is to record the present action height and investigate the neck truss-rod movement (you never know....) and the side dot depth:



But, before I take the neck off, I am going to cut a new nut at Jack's preferred position and string spacing and...well...just try it!  This will also allow me to see where the fretboard edge will need to be and also how much those top dots are going to be out of line and also play it at the string spacing and make sure it isn't going to be too crowded for comfort:



So, if I have a piece of bone in my bits box, that's what I will be doing tomorrow :)  That and having a dig around in one of those epoxy black side dots ;)







Edited by Andyjr1515
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26 minutes ago, gary mac said:

Must say, Jack specializes in delivering challenging jobs.

Or has a habit of buying bad instruments... Wait a minute, he bought some from me. Erm, erm, Jack is really the most discerning person when it comes to buying excellent instruments. 😇

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Good news is that I found the bone pieces for the new nut - a triumph for the 'I know it's a mess but I know where everything is'  approach.  That and a decent dose of luck :)


So I should be able to have a play of the bass with the 35mm string spacing in the morning.  After that, the neck comes off!

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The progress on this will be a bit stop and start, but I've made some decent progress this morning.


First job was to work out the string centres for a 45mm nut.  And here was a bit of a mystery.  Most times, nuts are either equidistant centre line to centre line (where the gap between strings reduces slightly as the strings get thicker) or are equidistant gap to gap between the strings (so the centre lines are adjusted to account for the string thickness).


This was neither.  The centre lines actually got smaller towards the bass side and so the gaps got even tighter towards the bass side:



It's definitely the original nut because the neck finish actually went over the edges at the sides.  Curious!  Anyway, @Happy Jack and I have agreed that equidistant gap would be the best option :)


And when I marked it out, I realised that the B E and D were going to be in exactly the same position as before!  So the whole 3mm width reduction can be achieved simply by reducing the gap of the 2 treble strings to the same distance. 


And that means that, at 45mm, the strings aren't going to be too tight for Jack's playing :party:


I will still have to test it out myself, of course ;)


And so the nut had to come out.


First - and essential to avoid chipping the finish, a careful score of the varnish build up at the base and sides of the nut:



Then a tap from the side with a mallet and suitable drift:



One of the bone blanks I have in my bits box fitted perfectly:



And with the calculations of string centre positions done, out comes the jewellers saw...think HMS Victory during Trafalgar in the surgeon's quarters...



Then out with the Hosco nut files:



The above is the planned position of the nut - Jack's thought was to take all of the width off this side and maybe lose some of the epoxy dots in the process.


The nut slots will be cut to playing height after all the shenanigans, but this gives an idea of how much the top dots will be out of line given the change...answer, 'not a lot':



And it plays just fine - no cramped up feeling at all :)


So next, it's off with the neck!  


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So with the neck off, I could have a look at what might be going on.


This is always a bit of a bad sign - if the neck is pretty straight when the string tension is on it... tension that is trying to turn it into an archer's bow...then once the strings are off, then normally the neck would spring into a back-bow, with the truss rod still pulling in one direction but the strings no longer pulling in the other.  If, on the other hand, you still have a forward bow:



, then the truss rod is not doing at all what it is designed to do.


There are usually a number of possibilities.  This is a single action truss rod (there are other possibilities with 2-way rods).  Some of the more common possibilities are:

1 - it hasn't been tightened enough/at all

2 - the rod is broken or thread stripped

3 - the rod anchor point or nut collar are crushed or cracked

4 -  the rod has reached the limit of its adjustment...usually that the nut is bottomed on the truss rod thread

5 - the rod IS operating, but the inherent bow in the neck is huge and the fully adjusted rod still isn't enough to create a back-bow or even straighten it before it reaches the limit of its adjustment (in this case, the nut bottoming on the thread)


And, to an extent, you can confirm or eliminate some of these without having to do anything drastic like taking the fretboard off.  First is to try to loosen the truss rod nut...


With a single-action rod of this design (please note - do NOT try this with a two-way or a modern double-bar one-way rod where the nut is welded to the rod), the nut should unscrew and be removeable.  So that's what I did and it told me a number of things.


Nut off - note the relief gap:



So this has eliminated possibility 5.  If that had been the case, the relief gap would have increased markedly as the truss rod was loosened.


But I noted other things:


- The nut was fully bottomed on the rod.  It took considerable effort to 'crack the joint'.  But it did then unscrew.  The thread, though, was tight - and I could feel the torsion on the rod as I unscrewed it.  This eliminates possibility 2 and confirms possibility 4


- But even when fully tight, the rod isn't applying any back bend to the neck.  This starts pointing to possibility 3.


But there is an easy way of checking before any drastic action is involved.  Fender do some thick small OD washers to give a bit more movement to rods that have 'bottomed out'.  It's worth trying that before taking the more drastic action of trying take the fretboard off.  The washers are completely non-standard size - it will be as quick for me to get some posted rather than trying to file some larger ones down.


But it might...just might...remove the need to attempt to get the fretboard off.  So that's the next step  :)






Edited by Andyjr1515
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Washers on order.  The only place to get Fender originals at the moment seems to be USA (£4 for item, £130 shipping, 200%VAT & Customs, delivery estimate 'sometime in 2021 unless difficulties encountered') but, looking at the size of the hole and the rod, I reckon 3BA brass washers will fit.  Ordered, £3 including postage, should be with me Wednesday :)

Edited by Andyjr1515
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57 minutes ago, TheGreek said:

Don't know if they are interchangeable (don't see why not) but Yamaha sent me some TR nuts with longer thread so that there is more adjustment. I would donate the spare to the project but I have no idea where I put it - in "a safe place" obviously.

It's the thought that counts, Mick :D


I think the Yamaha will be metric and I'm pretty sure this is imperial.  The washers should be with me in the morning.  If they don't work, then it will be a fretboard removal in any case.  Many thanks for the thought, though :)

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Well....I won't know for certain until the morning but - I think we have a working trussrod.


It's presently sitting on my bench with a distinct back bow and - as it was tightened to get there - it felt 'right'.


I will judge it properly in the morning because there may be a wood movement under the extra pressure over time - but I think there's a better than evens chance :)


I'll let you know first thing tomorrow.

Edited by Andyjr1515
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1 hour ago, Happy Jack said:

That is outrageously good news!

It is :)


And the even better news is that it has held the back bow all night.


So it is almost certain that the neck is fully functional, and that means no fretboard removal and a significantly lower risk of the fretboard or neck becoming u/s.


I have some filing work to do to enlarge the inside diameter of enough washers to give the full present and future adjustment but I can now start thinking about the narrowing of the neck and start on that pretty soon.


Might also be time to start ordering some timber for the fretless neck  ;)




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One of the things that Jack, Silvia and I talked about in the pub was the large retro-installed side dots, which are to be removed, and whether taking all of the width off the bass side only might take enough off to take out the drill holes too.  Unfortunately I think the answer is almost certainly 'no' - the black epoxy is fairly easy to get out, but the drill holes are pretty deep:



The good news, though is that they have been drilled with a brad-point drill so it should be relatively easy to clean them up - maybe even slightly bigger to take out the original small dot too.  If I can find a plug cutter the right size, the plan would be to cut some maple plugs.  It won't be even close to invisible but, with the luminlays also in the same positions, it shouldn't be quite as much 'in yer face' as the present black ones.


The other thing we talked about is me swopping the truss rod nut to an allen key one - so a Fender Standard American truss rod nut from Allparts is on its way...should fit :)


So next step before actually reshaping the neck, is to string it back up and make sure that it holds the set relief under full string tension.  And that's what I'll do tomorrow :)



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27 minutes ago, Andyjr1515 said:

The other thing we talked about is me swopping the truss rod nut to an allen key one - so a Fender Standard American truss rod nut from Allparts is on its way...should fit :)


I assumed you would only be able to do that if you replaced the entire trussrod. If you can replace the nut with the rest of the trussrod in situ then that's jam all the way. 🙂

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