FINISHED! Dreadnought Acoustic

Andyjr1515

Hi

I've started in earnest to build the dreadnought acoustic I mentioned in one of the other threads.

It's a surprise present for a significant birthday next year of our old-gits-band's vocalist.  It's OK...there is no chance of him seeing this thread  

I'm using a standard design with spruce top, lacewood (London Plane Tree) back and sides, mahogany neck with central walnut splice and ebony fingerboard 

Progress so far - apart from getting all the woods and templates together - is:

• Assembly mould built:

• Sides thicknessed down ready for final sanding (about 0.5mm to come off):

• Top and back thicknessed ready for final sand, joined and cut:

The line down the middle of the spruce is just greaseproof paper I used when I was clamping the two pieces - that will come off with the final sanding - it is a superb piece of tight and vertically grained spruce...

Next week I'll get onto bending the sides!

Andy

Skodadad

Watching this as I fancy a go at an archtop. I have a 10" planer thicknesser I have no idea how to use sitting under a tarpaulin in my garden lol.

Andyjr1515

Skodadad said:

Watching this as I fancy a go at an archtop. I have a 10" planer thicknesser I have no idea how to use sitting under a tarpaulin in my garden lol.

This will be quite a different construction to an archtop electric, although there are some bits that use similar techniques.  

A carved top arch-top has been on my 'must get around to doing...' list for ages!

I'm green with envy of anyone who has a planer thicknesser!  My thicknesser is FANTASTIC, but you do have to have at least one straight surface to start with or it's banana in = banana out  

Skodadad

Pity you are so far as this is sitting here doing nothing until I get a shed. Probably be rusted away by then too

Andyjr1515

Skodadad said:

Pity you are so far as this is sitting here doing nothing until I get a shed. Probably be rusted away by then too

That's my problem too. It's not so much the lack of a machine as much as a lack of anywhere to put one

Andyjr1515

Got the sides down to final thickness (scrapers and sanding block).  

Unless Mrs Andyjr1515 has something plotted that I don't know about, I may well have a go at bending the sides tomorrow 

Andyjr1515

Well, Mrs Andjr1515 had indeed plotted something, so I finally got to bending the sides this morning.

One of the wiser purchases in the past year was an Ibex electric bending iron (those of you who remember my human blow-torch used in my last acoustic build will nod in agreement):

It was raining outside so I risked the dragon's wrath and did it in the dining room!

Didn't take too long, even with the obligatory 'take it easy and don't rush' approach.  Here are the two sides drying off:

 

There's a significant amount of spare side wood...possibly to become a pickguard?

Andyjr1515

A bit more progress on this while I've been waiting for the varnish to dry on my single cut camphor bass build.

Got the roundel and purfling slots routed out on the top:

...and then glued:

Then all of the top braces cut and radiussed:

...and positions marked on the top.  I used the 25' radius dish to check the fit:

...and finally, into the go-bar rig with the 25' dish for gluing:

Andyjr1515

In the meantime, the sides are glued to the end-blocks and the kerfing glued:

 

paulnb57

Watching this with great interest Andy, that Lacewood looks lovely, are there any limits to your talents?

I'd better pop a Wow into the mix!

Andyjr1515

paulnb57 said:

Watching this with great interest Andy, that Lacewood looks lovely, are the any limits to your talents?

I'd better pop a Wow into the mix!

Yes there are...I may have reached them! )

shuikit

Really like the wood grain 

Andyjr1515

Thanks, @shuikit   

I'm hoping it's going to be stunning once it has had the finish applied.

Andyjr1515

With the single-cut camphor bass collected by a very, very pleased (phew!) guy, and the rain stopping any other activities, I thought it would be a great moment to plunge into the black magic of shaping the braces and 'tap-tuning' the top.

The rough shaping of the braces is like this (there's still a tiny cap to put onto the join of the X brace which is important for tone as much as strength...more later):

In brief, the position of the peaks in the braces is important.  Happily, 70 odd years of other people's experience says that this will be OK.  Who am I to argue.

Secondly, the thinner the braces, the more bass will resonate.  Also harmonics start developing the thinner things are, but that - if taken too far - is at the expense of strength.

So, in very basic principle, you tap the top, holding the top up by the very edge, listening for tonal differences between the bass string side and the treble string side.  You shave tiny amounts off the depth of the braces until you start hearing the top ringing more than a dull thud, then thin the appropriate braces more for a bit more bass in the appropriate places.

There are some FASCINATING videos on YouTube on this, including a Physics lecturer going into considerable detail.  With me - I get to the point where it rings, where I can hear a number of notes in the harmonics and where there is a tangible difference in pitch between tapping on the bass side and the treble side   And then I stop... because I don't really know what I'm doing beyond that 

Andyjr1515

The next step of the sort the fitting of the top.  Because the top itself is slightly spheroidal, the sides need to be too.  It's a bit painstaking, but, after a rough planing at each end, I use the radius dish again, but this time with a couple of lengths of sandpaper stuck with double-sided tape:

Eventually, you get a shape that suits the bowed top:

Next big step will be gluing it so, on the principle of 'measure twice and cut once', I make sure that the top is going to be fully sealed by popping a few violin clamps on and double checking from the outside and inside:

Next step is applying the glue...

Andyjr1515

And gluing commences:

Thinks....I must buy/make some more violin clamps

Andyjr1515

Rough trimmed ready for flush routing:

Still quite a bit to do on the top, but also started the back.

A bit scary this - having got the back down to just over 2mm, I needed to inset a 1 mm central decoration strip.  I had a 3mm router bit and figured that if I used a 3mm allen key as a spacer, I could cut the 6mm in two passes (one with the allen key and one without) along a straight beam with the Dremel precision router base:

It worked!

Strip safely in, glued and excess wiped off:

paulnb57

Good work Andy, how do you rate the Dremel router base?

Andyjr1515

paulnb57 said:

Good work Andy, how do you rate the Dremel router base?

I wouldn't be without it, Paul.  I use this a lot in various bits of a build.  

paulnb57

Thanks Andy, I may invest...

BigMonka

Andy, I just caught up on this thread - it's amazing!

How did you get the back and top so thin? Is it just running the planks through your thicknesser and then gluing? But how do you get a good solid glued joint when it's only 2mm thick?!