Finished Pics! Dreadnought Acoustic Build - Black Limba

Andyjr1515

A bit more progress.  I've been concentrating on the neck joint.  However, because an acoustic bridge and neck are pretty limited in adjustment once they are in place, you do tend to have to go about things in a fairly strict sequence.


To work out the neck angle, you need to know where the bridge is going to sit and how high the fretboard is going to be.  So that means radiusing the fretboard.



I made myself a fairly rough and ready radiusing rig a few years ago:



 but Matt - who the guitar is being made for - wants a 16" radius.  As that would mean making another couple of ends...and the rig being a bit wobbly at the best of times, I invested in a G&W rig.  Pricey when adding some extra radii, but WOW - SOOOOOO good!




Ten minutes got me here:



Then another ten minutes with a radius block got me here:


Then out with the jewellers saw and the Dremel:



Then a touch of epoxy mixed with ebony dust, and another sanding with the radius block gave me this:


So now I could work out the neck angle

Andyjr1515

Basically, you want a straight edge laid on the top of the fretboard, to just about sit on top of the unsaddled bridge (which has to have been seated to accommodate the 25 foot spherical radius of the guitar top).

To measure the required angle, I used an engineer's protractor:



Then got out my routing jig.  Based on the fancy O'Brien jig, it's a bit of knocked togetehr home-made job made mainly from an old B&D Workmate plus a couple of G&W templates:



It's a bit rough and ready but does the job.




Then the scary bit.  I take off the neck jig, and clamp the body, suspended from the workmate clamped by a couple of cork-lined jaws...and a bunch of old towels underneath just in case it drops off! : 




And to my not inconsiderable surprise...it fits! 

BigMonka

Stunning as always Andy. Are there going to be any other fret markers?

Andyjr1515

BigMonka said:

Stunning as always Andy. Are there going to be any other fret markers?

Thanks!

No - Matt just wants inlays at the 12th.  There will be some blue luminlay side dots, though.

I've just added the frets - all of a sudden it looks like a guitar    I'll post some pics in the morning

Andyjr1515

With the frets in, I will now add the luminlay side dots and seal the tang slots with epoxy mixed with ebony dust.  Then, after a quick sand of the sides, it will be ready to glue to the neck, which can then be carved to final shape.

Always time for a quick mock-up, though

Andyjr1515

I know there are cheaper alternatives, but I love Luminlay.  It is SO easy to fit.

I do recommend use of a good quality bradpoint drill (I use the Fisch ones from Axminster) but it's basically:

• Measure and mark the centre with a sharp centre punch
• Drill 3mm or so depth
• Check the stick goes in OK
• Pop a drop of CA on the end
• Push it into the hole

 

• Cut flush with a razor saw
• Sand the edge

Less than an hour in total and here we are:

 

 

Final job is filling the tang slots and it's ready to fit to the neck

Andyjr1515

The overnight job was gluing the fretboard to the neck.  I use radius sanding blocks as my cauls - you can put a huge amount of clamping force on them and they apply the pressure to the sides as well as the middle.

Ready for neck carve  

 

The neck is bolted on with stainless machine screws and some decent threaded inserts.  Once It is all set up, I may well be gluing the tenon too - bolts alone work well, but I do find that the heel blocks can relax a touch over time and therefore can have a tendency to slacken off a touch.  Easy to re-tighten but not ideal.  In that the neck should never have to come off, I've come to the conclusion that using the bolts to ease getting all of the angles and fit right - and then glue and bolt - might be the best of both worlds.

I did do a dovetail once.  But my GP told me that I must never do that again because the emergency services are just too stretched to cope with another self-inflicted heart attack... 

Here are the inserts: 

TTony

Andyjr1515 said:

The neck is bolted on with stainless machine screws and some decent threaded inserts.  Once It is all set up, I may well be gluing the tenon too - bolts alone work well, but I do find that the heel blocks can relax a touch over time and therefore can have a tendency to slacken off a touch.  Easy to re-tighten but not ideal.  

But if the wood needs to move a bit as it settles - natural material and all that - and if you've both bolted & glued it to prevent any movement, won't that increase the risk of the pressures causing a split somewhere?

Or is the movement stress not enough to cause a split, just enough to ease a joint apart if its not glued and bolted?

(I am, obviously, no expert!!!)

Andyjr1515

TTony said:

Andyjr1515 said:

The neck is bolted on with stainless machine screws and some decent threaded inserts.  Once It is all set up, I may well be gluing the tenon too - bolts alone work well, but I do find that the heel blocks can relax a touch over time and therefore can have a tendency to slacken off a touch.  Easy to re-tighten but not ideal.  

But if the wood needs to move a bit as it settles - natural material and all that - and if you've both bolted & glued it to prevent any movement, won't that increase the risk of the pressures causing a split somewhere?

Or is the movement stress not enough to cause a split, just enough to ease a joint apart if its not glued and bolted?

(I am, obviously, no expert!!!)

No, I don't think so, @TTony ;.  The joint itself shouldn't move - it should act as one solid block as it does in a glued dovetail joint.  

I think it's the relatively soft mahogany of the head block that crushes slightly over time under the pressure of the bolt heads.  So the only thing that actually moves is the tightness of the bolts themselves - but that, of course, then makes the neck joint loose and, under the string pull, that could indeed damage the joint itself.  So my aim, right or wrong, is to make sure the joint itself can't move whatever happens to the bolt tightness.


Mind you, it is Andyjr1515 we're talking about here...so I'm probably completely wrong

TTony

Andyjr1515 said:

Mind you, it is Andyjr1515 we're talking about here...so I'm probably completely wrong

If there's a bet between who's more likely to be right on any aspect of guitar building - you or me - my money would be on you


I didn't think about the compression effect on the mahogany block.  That makes sense.    And then the "glue it" solution makes even more sense.

Andyjr1515

TTony said:

Andyjr1515 said:

Mind you, it is Andyjr1515 we're talking about here...so I'm probably completely wrong

If there's a bet between who's more likely to be right on any aspect of guitar building - you or me - my money would be on you

Well...I'm not sure about that

What I am intrigued about is what the commercial guys do.  Maybe they pre-tighten the bolts in the blocks before they fit the neck and then also, when they fit the neck, maybe tighten those tighter than I would generally be comfortable with.


I'm pretty sure that compression is a real phenomenon, though.  I've come across it when clamping some woods over extended periods of time (dry joints so not affected by glue drying and shrinking).  Quite often when you come back to them, the clamps are much looser than when initially applied


Like a lot of things to do with acoustic building...and wood, I dunno  

Andyjr1515

By the way, @TTony - you'll love it when I get round to showing how I glue binding on nowadays.  Talk about spitting in the eye of convention...

TTony

Andyjr1515 said:

What I am intrigued about is what the commercial guys do.  Maybe they pre-tighten the bolts in the blocks before they fit the neck and then also, when they fit the neck, maybe tighten those tighter than I would generally be comfortable with.

Use harder wood?

Seriously though - perhaps their timber is more seasoned and less prone to movement/compression, or is pre-treated in some way?

Or perhaps they just glue it too ...

Andyjr1515

This is the other crazy Andyjr1515 method I mentioned earlier, @TTony ; - my way of attaching wooden binding.  For better or for worse

And here, I repeat what I have said many times before.  This is just the way I do things - don't assume this is the way things should be done!

I made a start with the top binding which will have an inner feature line of black/white/black purfling and then some Rocklite Ebanol outer binding.

I have to say, I HATE routing acoustic guitar binding channels.  With a spheroidal top, it's really tricky - especially as you are working with 0.25mm tolerances.  I use a Stewmac Dremel attachment, but I wouldn't recommend it - there are just too many times where tiny adjustments in angle or tilt of the Dremel (difficult to avoid with it being top-heavy) you can gouge up to mm too deep!  But, so far, I haven't found anything affordable as an alternative

Anyway - after HUGE amounts of care and re-runs and tidying up with a very sharp chisel, it is as good as it's going to get.  And some of it is OK - 

 

 

The next bit - gluing the purfling and binding - I also used to hate.  I tried all the traditional methods, from fibreglass reinforced tape to bicycle inner tubes, to ripped sheets and tourniquets.  And - with everything now completely hidden, you could never see how well it was positioned and clamped. I never took all that stuff off the next day to find a tight-fitting, in-place binding... 

So I had a brain wave - and, honestly folks, I think I'm the only person in the world who does it this way - why not IRON it on like I iron on veneer?????

And that's what I've done the last two builds that needed binding - and I can't see any reason not to do this for all of my future builds.

For those who haven't seen my veneering threads, basically I use decent quality PVA wood glue, paint both surfaces with it, let it dry and then iron it on.  The heat of the iron melts the PVA between the two parts, the two parts float a touch so can be positioned precisely, you hold it there10 seconds or so for the glue to re-solidify and that's it! 

You get instant confirmation that the joint is good or not and - if it isn't, it is fully repeatable...you just heat it up again and it re-floats, you re-position it and let it cool and it's fixed.

That bit is not an Andyjr1515 exclusive.  But I don't know of anyone who also uses the same method for applying timber bindings... 

This is my kit.  You can just a well use a household iron...I just use the smaller one for ease of use: 

 

You can see at the bottom of the photo the length of purfling with the PVA drying (takes about 15 minutes).  I've already painted the slot with the same glue.

Then I just iron it on: 

 

I do about an inch at a time, hold it in place for 10 secs and then move on to the next inch.

To do the full top, using two purfling strips, took about 20 minutes.  Bit of sanding showed me this - all round! :

 

 

And even now - if I saw a gap I didn't notice (there wasn't one), I could have just repeated the iron at that point and fixed it.

The outer binding will need pre-bending - but when I get round to it, I will be ironing that on too:

 

 

I'm sure there are lots of reasons why this is a really bum method - but it certainly works for me...

Andyjr1515

The Rocklite Ebanol bindings were pretty easy to bend over the bending iron - much, much easier than real ebony!

So same MO as the purfling:

  Only difference is that each couple of inches takes a minute of two rather than 30 seconds.  It is essential that both layers of glue melt together and the extra thickness and width of the binding takes more heat.  Also, they take longer to cool and re-solidify the glue...more like 30-45 secs.

Again, though, this is a fully repeatable process.  So for a gap like this below - while you are doing it or after you've finished - it can be simply reheated, then pressed in place and held to cool with the gap closed:

As a matter of fact, that is what I do.  First time round I concentrate on getting the sides attached and the shape held, seating the binding but not worrying too much about small gaps, and then I go round the whole thing a second time, this time reheating JUST to seat it properly - because either side is still solidly glued, there is no danger of each couple of inches pulling out of shape.

And after a satisfyingly short period of time, I've got the first half of the top done

 

FelineGuitars

lovely stuff

Andyjr1515

FelineGuitars said:

lovely stuff

Thanks   Very much appreciated 

TTony

Andyjr1515 said:

The Rocklite Ebanol bindings were pretty easy to bend over the bending iron - much, much easier than real ebony!

Rocklite?

You use Rocklite rather than the proper stuff??

Ruined it for me now.






Of course, I'm joking.


Still beautiful work from a proper craftsman.

Andyjr1515

Thanks @TTony ;

Just an irrelevant aside, but I actually have the first guitar in the world fully built (ie back, sides, top and fretboard) in  Rocklite Sundari.  (Well - you've got to be famous for something )  It's a Gillett Contour 6 hybrid.  It's an intriguing guitar and equally intriguing material.  

This binding is the first time I've used it in building.  It will be interesting how it goes.  It certainly looks like ebony...

Andyjr1515

Got the second side of the top binding successfully ironed on  



And added a couple of swifts to the headstock.  Normal MO - cut out with a jewellers saw; routed with a Dremel precision router base and 1mm bit; glued with epoxy mixed with wood dust and sanded:




All of that was just putting off having to reset the neck angle - which is a beggar to do once the fretboard is fitted.  Results of that little adventure next