Andyjr1515

I do thank you, @Mykesbass But I know when something is out of my league...

Yes - just flipped over. It's been strung up and unstrung so many times (which is why I always use a 'sacrificial' set for this stage), I'm not surprised that the saddles have started turning over in disgust

Well - my bits box is certainly wide and varied. As I vaguely remembered, I do indeed have some genuine and unused Mustang/Jaguar slide switches. The great thing is that I therefore also have the proper short and threaded screws This is where @ped and I agreed it should go: For the pickguard I drilled the corners of the slot, cut the middle out with a scroll saw and straightened everything up with a couple of needle files: For the chamber, the same as the pickup chambers - hog out with a forstner bit and then chisel the 'waves' straight. This is before I did that latter step. For cable access, I simply need to drill a short hole between the controls chamber and this new switch chamber. And it's in: Tomorrow will be sorting the two pickup ring 'skirts' if I can find the material I'm hoping to use. And after that it should be all of the actual construction work done - it should be then just a case of wiring it up and putting it back properly together

Just catching up. Welcome to the challenges of finishing - it's a rocky climb! The most important thing is that you have a neck and body that fit nicely and the strings and bridge line up! Just reading your thread, there are many things that can affect adhesion of paints (which is why, generally, I don't do paint finishes), but one of them is certainly that many, if not most, manufactured bodies have a residue on the surface and always benefit from a thorough sanding before doing anything. It may or may not have anything to do with the problems you had (did you use a primer?) but I was reminded of this when I saw the tung oil result...it looks surprisingly light coloured. Is that residue of the white paint there too? If so, it might be worth giving the body a rigorous sanding - right down to proper bare wood and then try the tung oil (other oils work OK - Tru-oil; Danish Oil; etc) which might soak better into the wood, darken it and be quicker to dry. The test if you are sanding is to take a clean facecloth or dish cloth, soak it in water, squeeze it out and wipe the surface of the sanded wood. The dampness should darken the wood as the water soaks into the grain. Any residue of manufacturing or previous finishes will show up as light patches. When the dampness darkens the wood and is pretty even, then you know you are down to un-contaminated timber and then you can let it dry before starting the first 'soak in' coats of your preferred finish.

Not yet. If it was a slide switch on the scratch plate, it would make sense for it to be close to the volume knob. I'll have a ponder tomorrow

Out came the scrollsaw and off came the excess pickguard: Unfortunately, @atsampson , I don't think the offcuts are quite long enough to completely fill the narrow, but long gaps. After doing this sort of thing a few times, one is relatively relaxed hitting a 56 year old icon with a Forstner bit...well, definitely relatively And, again using chisels and mallet, the chamber is cut: And it fits! (Big phew!)

Yes - that's a decent thing to try. It is such a small gap it might be 'just enough'. I will try that but if the glue line shows pretty much as much as the gap, then I can always revert to the original thought of a couple of mm skirt underneath the pickup ring.

Hi @Zephyr You are right to be a bit confused - because there is a lot of confusion generally in the guitar and bass worlds about truss rods and shims. So - a quick explanation. Truss rod Its purpose is to make the neck straight. Period. The string tension, when fully tuned up, tries to bend the neck like an archery bow (picture courtesy of Guitarless.com) : - The trussrod's job is to bend the neck the opposite way to end up with a completely straight neck. - Yes - the trussrod adjustment affects the action height - but that is not its job. Shims/Neck angle If your neck is straight, when under full string tension, and the action is too high or too low for the saddle height adjustment to be able to compensate, then - for a bolt on neck - it is the neck angle that needs to be adjusted. And a shim in the neck pocket is what is usually used to achieve that. I always find this the most useful pic to explain exactly what is going on (Not my diagram. It is used quite often by different folks so I don't know who to thank) : Using a shim in the neck pocket is nothing at all to do with bending the neck at the upper frets. Trust me - the neck is never going to bend there from a shim (so yes. your question was quite right) If your action is too high, then you put a shim at the very back of the neck pocket which then lifts the back of the neck and tilts the whole neck down ('down' from the perspective of the above pictures). This lowers the action. Ref the above, Pic 2 is where you are starting from with too high an action; Pic 3 is with a shim at the back of the pocket; Pic 4 is if the shim is too thick and now the action is too low and the strings are pressing against the fretboard) If your action is too low, then the shim goes at the front of the pocket, which tilts the neck up. Usually, it needs no more than the thickness of a credit card and often less. Any material can be used as long as it won't crush (and so cardboard is no good; a slice off a business card is OK; a slice of old credit/store card might be a bit thick but is ideal as a material). Here's a shim that I found, under quite a fancy bass I am working on, when I took the neck off. It will have been put here to lower the action enough for the saddle adjustment to be able to do the fine tuning. It is around 1mm thick and will tilt the neck downwards, which lowers the action. : If the action was too low, then a shim would be put here: So, back to yours: - You want to get the neck as straight as you can to start off with. Truss rod adjusts this. Only measure when the neck is on, the strings are on and tuned up to pitch. - As mentioned above, the simplest way of checking is: Hold the G down at the 1st fret and the 16th fret. At the mid point (7th/8th fret) there should be a just perceptible gap between the string and the fret. If it is hard down on the 7th or 8th fret, then the truss rod is too tight and creating a back bow and needs loosening. If there is a gap, but it is anywhere more than, say, the thickness of a business card, then there is still too much bow in the neck and the trussrod needs tightening a touch Once the neck is straight under string tension, you can then look at the action height. If you can get a decent action with the saddle adjustment, then simply do that. But, if even at the top or bottom of the adjustment range of the saddles the action is too high or too low: - lower or raise the saddles to the mid point of their adjustment range - if the action is too low, try a shim in the front of the neck pocket - if the action is too high, try a shim at the back of the neck pocket

This ^

@ped and I had a discussion about the pickguard positioning. I had noticed that most of the fixing screws were squiffy and, when I took it off, while it is clearly a genuinely old pickguard, I had wondered if it had been replaced at some stage - especially as the P pickup was also at an angle, as with the bridge and bridge pickup. Could it be shrinkage of the original, @ped speculated? Also, as fitted, there was a gap - and uneven at that - between the pickguard and the controls plate. And so, was the control plate original (especially there's an 'extra' screw hole underneath when you lift it off)? Whatever, there was a choice: leave it with squiffy screws; butt it up to the heel; butt it up to the control plate. And it was that last option that @ped decided - leave a larger gap at the heel end but butt it up to the fitted jack plate: And only two holes lined up...the rest each being around 2mm out. And guess which those two were? The two were the ones next to the control plate And so @ped was absolutely right. Almost certainly this is the original scratchplate AND controls plate and the scratch plate has indeed shrunk that much. But what about the squiffy P-pickup? Well... the wood underneath isn't squiffy - almost certainly that angle has resulted from the same problem. This was further supported by the fact that the P pair was hard against the plastic when I tried to lift the pickguard off. Everything else supports it - the pink stains on the back of the scratch plate, the original non-yellowed pearl where the original thumb rest was. All the screw holes except two were plugged with B-B-Q skewers (no need for with-grain large plugs here) and re-drilled and screws re-fitted nice and straight. And then I could position the neck pickup ring. It covers most of the P-pickup hole, except for the wedges left by that twist. Position was checked against the centre line of the fretboard dots... ...and couple of fixing screws fitted so I don't lose the position. Finally, the chamber shape marked for cutting out with the scroll saw in the morning

You’re right @fleabag Can’t find one anywhere.

It took a couple of goes to get the bridge in the correct position (good thing about there being so many fixing screws was that I only needed to use two for the first trial - enough for being able to fit the strings straight but un-tensioned. Those first two screw holes will need to be re-plugged ) but got there in the end in terms of the strings lining up correctly with the fretboard dots: And with that done, I could start on the bridge pickup chamber. Those who have followed my previous threads will know that I detest routers and certainly wouldn't willingly use them on something as old and fragile as this. Instead, I start with drilling the corner radii and positions of the pickup base plate and scribe a line tangential to the two corners: Next, I rough out - for a full humbucker I would use a Forstner bit but, for this extension to the existing Jazz p/up chamber, just a brad-point drill: And then next, out come the sharp chisels and mallet: Don't worry - the red next to the chisel is some silk from the test-strings I use for the on/off/on/off malarkey that is necessary for this kind of work. The blood from my missing finger is out of picture on the carpet And twenty minutes later, we have a chamber: Finally, a quick restring to check it does actually line up. Phew! So tomorrow, I will re-plug the two erroneous bridge positions, take out the P pickup and start thinking about both the fitting of the Thunderbird-ish neck and the surrounds to hide the gaps.

For plugging the drill holes that I'm just about to make for the new bridge screw holes, dowelling is no good. Why? Because the grain runs along the length of a dowel and the circular bit is therefore end grain - which has insufficient screw-pull-out resistance. And so I use a plug cutter on some similar strength/softness wood to the body. For this one, I'm using mahogany which is closer in hardness to what is probably an alder body than, say, using maple. With a following saw cut, it releases the 'across the grain' dowels: And the plugs are in waiting for the wood glue to fully set. All being well, tomorrow I will be able to drill to refit the bridge in its straightened position and then I can string it up with a couple of spare strings so that the pickup positions can be accurately marked

And so, on the basis that everything affects everything, before I start plugging and fixing the new bridge, are the pickups chosen in @ped's concept going to fit? The two pickups that @ped got sent to me are a hot Ric-ish Gemini Pickups 'Surfrider' for the bridge and an equally hot Thunderbird-ish Gemini Pickups 'Degenerate' for the neck Here they are in their approximate positions: The bridge Surfrider will need a sympathetically chosen surround made as it is slightly narrower than the J and there is the base plate to hide. It will be hard against the bridge as with the original J. The ring with the Thunderbird so very nearly covers the existing P - it only fails because that is at the skewed angle and that leaves a teeny gap. I will make a thin plate under-ring just a couple of mm larger than the metal ring to hide the gap. There will be switch(es) - Mustang slide switches if they will fit - for coil tap. And that should be that! Just got to do it

And so to that bridge. Using my long rule running up the fretboard, I positioned the bridge square with it at the correct length. Then I checked the two string runs from the nut slot to the saddle grooves: So - did ANY of the bridge holes line up? One! The far left above the E saddle. And only one of the through-body holes (the A) although all of those will be usable. It wouldn't have made too much difference if none of the screw holes had lined up - but it meant that, without any plugging and redrilling, I could secure the bridge to stop it sliding about... ...while I double checked and triple checked and quadruple checked, etc, etc, etc

It does...but no

Both

One thing you learn messing about with guitars and basses is that, especially in terms of geometry, everything affects everything. Until you start unscrewing stuff and lifting covers and components, you can't be certain what has changed in the past 56 years, and what was always like that...and, even then, was it 'right'. It's one of the most interesting aspects with working on old instruments (that and the 'exhilarating' terror of making a mistake ). And then there is the other aspect - even if something always was wrong - is it better to correct that...or correct everything else around it. And here a different type of logic might apply - and often this is where pragmatism and experience come in. Let me explain. The bridge is at an angle, but the strings are lined up well down the fretboard: The centre dots are in the middle of the A/D string gap at both nut and heel ends; the distance between the E and G and their respective fretboard sides are even. Andyjr1515 Golden Rule: If this is the case, and the bass plays well (it does) and the action is able to be low without buzzing (this is perhaps the lowest action - in terms of across all strings - of any bass I've worked on) then assume, unless some aspect later-on is irreconcilable, that this is the datum. So my plan, as it stands, is to do NOTHING with the neck. In fact, if I can be sure of protecting everything, I probably will not even take the neck off. Ideally, I don't want to touch it at all. And so, for the time being, I have a datum. And so what about the bridge? If the string runs are assumed to be correct, how are they in relation to the bridge? Have a look at the strings relative to the lines of the saddle adjustment grooves: Note also that gap between the control plate and the scratch plate - it's askew. So - critical question. Has the bridge been repositioned? Did the modder who installed the pickups erroneously put them in at an angle and then had to twist the bridge? Only one way of finding out Golden rule with working on old basses...make sure you know which particular screw came out of which hole...it matters! Hmmm...interesting. I would pretty much guarantee that this bass has never been been resprayed and, as such, any adjustment of the main screws would show. I'll come back to the two small screw holes next to the pickup cavity. The four large holes at the back are the string-through holes. I reckon that bridge was askew from new: So next question - could it be straightened without affecting the string runs?

In terms of bits and layout, not quite. In terms of putting a smile on @ped 's face, then hopefully

Now, folks, stop right there! I know, I know, I KNOW!!! And more to the point, so does the owner of this 56 year old beauty (the bass, that is), our very own @ped And the bass is a delight. My Canon SLR doesn't cope well with reds, but this gives you at least an essence: OK - to stem the torrent of 'DON'T DO IT' posts, it is clear that it has already, in its past, been significantly and irreversibly modded. I'm pretty sure this is closer to what it would have looked like out of the factory: So, originally: no bridge pickup; early, smaller, split neck pickups. And so to @ped's wish and desire: - The present PJ pickups, while parallel with the bridge, are absolutely not square to the strings and neck. So is it the bridge that is wrong? And if so, was it always? Or was it the replacement pickups that were put in skewwhiff? Or is it the neck? Or all of the above? - The pickups aren't as originally fitted. Neither the bridge nor the neck pickups are original. Nor is the P the original size. So the body has already been retro-routed and the scratch plate has already been retro cut. - And so, if @ped fancied some different pickups, there would be no major impact on the value...and it's probably a keeper anyway (and if he doesn't want to keep it, then I will - and I don't even really play bass! It really is a thing of beauty) - And if different pickups were to be fitted...well could the bridge be straightened up at the same time? And there was a long PM discussion And it's now on my workbench

Decent thought, @Si600 but I agree with @Chopthebass. If you remember, Si, the Psilos fretboard is actually at body level - and so the strings are close to the body top: That would not be the case in this build where the fretboard sits higher than the body top.

Wow!

Absolutely - never... Looking splendid.

It's coming on very nicely

Those pickup winds look splendid! Nice work with the hand tools