Kurt Cobain “Jag-Stang”. Dry-run assembly with neck, body and key hardware

While I’ve been working on the JagStang neck, and waiting for the weather to turn favourable for paint spraying – I’ve been slowly bringing together most of the other hardware I’ll need for the build. Pickups excepted – I now have pretty much all I need to do a dry-run assembly, and check that it all fits together properly. It’ll be a first chance to check neck and body alignment, and to ensure that factors like the scale length and bridge positioning are correct. Since many of the hardware components are after-market parts from different manufacturers, (Fender, Warmoth, Gotoh, HOSCO), it will be important to ensure they fit together, and function properly.

JagStang – Checking how the main components fit together

One main advantage of a dry assembly before finishing the body – will be to locate all of the body-mounted hardware, and to drill out any required holes before the body finish is applied. Normally – I’ve tended to apply the actual finish to the guitar first, and then fit the hardware. This has a few scary moments – especially when drilling through brittle nitro paint finishes. There’s also the constant risk of damaging or marking the finish, before the guitar has even been played, and if something turns out not to fit – I’m much less inclined to fix the problem on the, already carefully finished, body.

However, when working on restoring, or re-finishing guitars – it’s always been a benefit that all of the layout and hardware attachment has already been done, in advance. When painting drilled-out bodies – there is always a slight risk that thick applications of paint finish might pool in an opening, and then “sag-out”, as the finish dries – but careful paint application should avoid that possibility, and the advantage of being able to “finalise” hardware placement so early and so easily – far exceeds any risk. Whilst I’ll be using quite a few “standard” components – the JagStang has an unusual configuration, and it will be hugely beneficial to try the components together, to make sure they’re compatible.

When I lay the various parts out for the first time, it becomes immediately apparent, just how eccentric the JagStang actually is. In comparison with many other Fender guitars – the form of the JagStang looks asymetric and unbalanced. When laid out and viewed vertically – the components look slightly jumbled and out of line. Those angled pickup openings in the scratchplate mean that the bridge always looks crooked, and the relationship of the bridge to the edges of the body is unequal on either side of the midline. Accurate “eyeballing” the placement of any of the main components is going to be impossible. However, once the guitar is viewed horizontally – in the playing position – the JagStang begins to look like it has some actual flow and appropriate “visual weight” to its’ form. That tiny top half to the lower bout – where the arm cutaway is sculpted – even begins to look supremely practical. The question is – how well does form follow function?

JagStang – Fender Mustang bridge, with Fender “thimbles”

The body for my build is by Warmoth, (Warmoth Custom Body CB29628), and is a two-piece alder construction, with a central join. Apparently – Warmoth don’t carry any JagStang bodies as standard stock – so I have to navigate the “custom body builder” interface on the Warmoth website, sit back, and wait for the six-week lead time and international shipping rigmarole, before I finally see the goods. However – the building and ordering process is, in reality, just a short, easy check-list, and many of the usual customisation options just don’t apply here. It’s a pretty straightforward recipe, and I get precisely what I ask for. The body is supplied, finely finished already, and all of the routs and openings have been cleaned out properly – with no burrs or loose edges. Nice job Warmoth. A quick check that my AllParts Jaguar neck fits the neck pocket correctly and, whilst I’m pleased to see that the neck fits well, I’m also extra glad to see that there’s enough “slack” to allow for a few layers of paint and lacquer. Too tight a fit – and there would always be the risk of cracking the nitro finish around the neck pocket.

My first concerns will be to get the neck and bridge relationship established and fixed. The JagStang uses a Fender Mustang tremolo assembly, and the body can be supplied by Warmoth to use either standard Fender Jaguar/Jazzmaster bridge “thimbles”, or a set of Fender “Tune-o-matic”, push-in bushings, for use with a TOM bridge. I’d like to use a sturdier Fender Mustang-style bridge here, and want to set up for a 7.25″ string radius, so that it’ll work best with my neck. (The Fender TOM bridge can’t be adjusted, and seems to only offer a pre-set 12″ radius. This might work better with Fender’s standard, 9.5″ necks – but even then – it’s far from perfect).

So – the first thing to check, is that the Japanese Fender Mustang tremolo unit I’ve obtained, (Fender parts number 003-5555-900), fits with a pair of Fender standard Jaguar/Jazzmaster “thimbles” (Fender parts number 005-4447-049), into the Warmoth, pre-drilled, openings and routs. Visually – the drilled holes in the body lie just off-centre, within the openings on the tremolo unit. I think there’s just about enough tolerance to place the thimbles – but it looks like I’ll probably have to drop the thimbles into final position after the bridge plate has been secured to the finished body. Nevertheless – temporarily fitting the bridge and thimbles, allows me to measure up the bridge, and it’s relationship to the rest of the guitar. The mid-line is easy to map out, and I can locate the position of the central tremolo plate screw, by centering and squaring the bridge plate against this mid-line, and the position of the neck pocket.

I use a conveniently-sized drill bit to mark the dead centre of the middle screw hole, into the relatively soft alder. I can then use the indent as a handy locator, and accurately drill-out the screw hole to the necessary dimensions. The bridge can then be secured with just that single screw, whilst I turn my attention to the neck, and it’s relation to the body, and to the bridge.

Warmoth Jagstang body, with an AllParts Jaguar neck

I’ve been working on the neck for some time now – but I still haven’t drilled out the neck bolt holes. Although Warmoth drill to standard Fender configurations – it’s quite difficult to pre-judge the actual neck bolt positions, without the benefit of any official templates or jigs. In most cases I’ve dealt with – I’ve tailor-fitted the neck, to the particular body in question.

Once the neck is placed in position, in the pocket – the neck is held, and slightly shimmed with a few thicknesses of paper along the long pocket edge. This should locate the neck in the ideal position, and add a small tolerance, which will help prevent it from eventually binding too hard on the painted finish around the neck pocket. With the neck held in position – the bolt hole positions can be traced through onto the heel of the neck, by inserting the neck screws through the body, and pressing them into the maple. The bolt holes can then be drilled out at the marked points, using a drill press and the correct drill-bit – having previously checked that the neck is held level and secure in a work-vise. It’s also essential to check that the bolts are the correct length, and that the holes in the heel of the neck are drilled to the correct depth. Get either one wrong – and you risk drilling right through the heel, and through the fingerboard.

The neck is fitted to the body, using four stainless steel bolts, and a thick, 2mm chromed steel plate. This is an old but perfect, unmarked (Mexican) Fender plate – but I chose it mainly because of it’s thickness. Many of the modern Fender plates seem to only be about 1.5mm thick, and some of these can flex badly if the neck bolts are ever overtightened. That can damage the finish, and also weaken the neck joint itself, over time. A thicker plate doesn’t distort so much, and as well as ensuring that the bolts are only tightened until they just “pinch” – I also use a black plastic HOSCO neck shim, to pad the plate away from the body.

JagStang – checking the neck alignment

Since the tuners have recently been fitted to the neck – I can now fit a couple of spare strings, and see how the neck and bridge alignment works out. I fit the bridge thimbles, and slip in a StayTrem, 7.25″ radius bridge, which I ordered last year, during the long Covid lockdown. I’ve asked John at StayTrem for a pair of “non-rocking” post bushings to be pre-fitted. I’m not sure this is still an option – but these posts have a pair of removeable, plastic bushings slipped over the top. These fill out the thimbles much more fully, and the normal rocking bridge motion is almost fully dampened. I don’t plan to use a tremolo with this guitar – so I don’t need the bridge to rock at all. Once I’ve slipped a temporary nut into the nut slot – I can tension up a couple of strings placed in the outer “E” positons, and see how things line up.

The neck is straight and true, and there’s an equal tramline at both sides of the fingerboard – so that’s good. Once I’ve confirmed the correct placement of the bridge – by measuring the scale length from nut to twelfth fret, and from twelfth fret to bridge – I can use the alignment, together with my previous measurements, to fine-tune the squareness of the bridge, and to mark out, drill and tap the two outer screws on the bridge plate. Once the alignment is confirmed, and the tremolo assembly is secured behind the bridge, across it’s middle – I can also mark, drill and tap the two remaining bridge plate screws, behind the horizontal bar which anchors the strings.

Looking at the bridge – it seems that the Fender string spacing is just a little bit bigger than the 52mm, StayTrem standard. In fact – the strings just slightly track inwards from the tail to the bridge. It looks like I really need a Fender Mustang bridge, where I think the “E” to “E” string spacing is 54mm or 56mm. I’ll use the StayTrem on my Natural Ash Jaguar build, and source a Fender Mustang bridge instead, for this JagStang. However – the StayTrem has been helpful in confirming the geometry, at this stage – and a good bridge like that never goes to waste around here.

JagStang – locating, scribing and fixing the scratchplate.

When Warmoth cut the body – I also had them make a couple of custom-fitted scratchplates, so I’d be sure they would fit perfectly. I asked for two plates to be cut – one in white pearloid, like on Kurt’s original Sonic Blue JagStang (Warmoth Custom Item PG3626272), and another in brown, faux-tortoise (Warmoth Custom Item PG3626273). I really like the look of a dark tortie guard against light blue – and since the plates are identical – I’ll always be able to interchange them as I wish, without too much complication.

JagStang – dry assembly, before finishing the body

The scratchplate fits perfectly – although I just had to scrape away the tiniest bit of plastic, around one side of the edge which runs parallel to the front of the tremolo plate. I always like to get small gaps and joins like this to run equally along their whole length – so just a few scrapes with the edge of a knife blade were all that was required, to get the join looking the way I wanted. Otherwise – the plate fits well around the neck as well. Once it’s ideal placement has been properly assessed and located – I can temporarily hold it in place with a few strips of masking tape, and then mark out and drill the screwholes into the body. Getting the holes dead centre within each pre-drilled plate opening, means I can tap the screws in perfectly straight. Stainless steel screws are lubricated with candle-wax, as they tap-in for the first time. The screws are tightened just until they pinch on the plate. Even though they are inserted straight – overtightening scratchplate screws can result in splitting the plastic plate – especially where the holes are drilled close to the edges of the plastic.

Mustang control plate, fitted with CTS mini pots, and a Switchcraft, mono jack socket

It’s impossible to find authentic Fender Mustang control plates here in the UK, at the best of times. Even the replica after-market parts seem to come and go, in terms of availability. I’ve had this Gotoh control plate on back order from WD Music for ages now – but it’s finally here in time for the test-fit. I want to use CTS pots and a Switchcraft jack socket with the plate – but the clearance in the rout looks tight. Once I’ve temporarily fitted two full-size CTS pots to the plate, and offered it up – I can see that the volume pot is located far too close to the end of the rout, and the plate just won’t sit snug up against the scratchplate.

JagStang – locating and fixing the control plate.

Fortunately – CTS also supply smaller-bodied, “mini-pots” which, although supplied with slightly longer shafts – can be stacked out with a spare nut underneath the plate – so that they sit at the correct height. With the smaller components on board – the plate can be positioned, and the screw holes marked out, drilled and tapped, as before.

JagStang – Locating and attaching the strap buttons

Finally, I locate and attach a pair of Fender American Standard strap buttons (Fender parts number 006-3267-049), with their white felt washers. Locating the one on the base of the guitar body is tricky – since it’s on an angle to the midline – but the central join of the alder wood blanks helps nail the ideal spot. With all of the body-mounted control components now in place – I can really begin to get an idea of what the finished guitar will look like. It’s surprisingly small – but it’s solid feeling, and still light in the hand. When it’s played sitting down – it’s perfectly balanced, and the drastically crimped “waist” of the body sits over the knee in the perfect playing position. It’s going to be an interesting project – dealing with some things I’ve never really considered before.

But first – I need to dis-assemble everything again, bag it up, and store it all away. Before I begin the finishing process on the body – I take the opportunity to lightly countersink around each of the holes I’ve just drilled into the wood. This will take the edges of the screw holes away from the screw threads, and will help ensure that the nitro finish, once applied, won’t crack and flake as the screws are tensioned, and the hardware re-attached.

3 Replies to “Kurt Cobain “Jag-Stang”. Dry-run assembly with neck, body and key hardware”

  1. What screws did you use to mount the vibrato to the body? Mine didn’t come with screws and I’d read that it used the ones for strap buttons, but I wanted to make sure. Thanks!

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    1. Hi – I used five standard Fender tremolo Mounting screws, (Fender parts number 0016170049 or 0016170000). From what I can see – they’re the same ones used on Jaguar/Jazzmaster and vintage style Stratocaster tremolos too. They’re 1-1/4″ long – with a non threaded section at the tremolo plate. I think strap button screws might work if you happen to have a few spare, but they seem to have a different code on some of my Fender spec sheets, (showing up as Fender parts number 0016188000). You can usually get a pack of 12 tremolo mounting screws from most Fender spare parts suppliers, and you’ll have enough left over for another project!

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