Thinking of building an acoustic ---> It's done!

fastonebaz

It's so joyous seeing this coming together, I'm totally rooting for it to sound and play satisfyingly well for you!

Misterg

vern said:

This is really impressive work. Thanks for putting this all together too, really interesting. 

Thank you very much! I've got the photos so I may as well do something with them  

fastonebaz said: It's so joyous seeing this coming together, I'm totally rooting for it to sound and play satisfyingly well for you!


Wow, thanks - I'm finding it quite exciting. I'm playing a bit of catch-up with the build, but it's not finished yet, so the outcome is still a mystery to all of us.

Jaycee

Enjoyng this build, love the rossette

Misterg

^Thanks  

After a few 'dry runs' where I clamped the back on, and then went around with a thin feeler gauge looking for gaps (I did find some and did a small amount of sanding to get rid of them), I had no excuses left not to glue the back on, I  (probably using too much glue). 

(The spreader inside is only loosely in position as I didn't want to glue the back on with stress in the sides)

I clamped the joint using strips of inner tube and bungy cord wrapped around screws in the outside of the mould. It did a great job of holding the joint tight and allowed complete access to the inside to do the clean-up (a few scrap blocks screwed to the top of the mould stopped the sides sliding through).

 

Still some sanding to do, but very pleased so far:

  

I didn't feel ready to finish the carving of the top braces, so pressed on with the neck instead.

I thinned the blank down a bit before gluing the scarf joint:

 ...and added a stack of blocks for the heel:

After cleaning it up a bit:

 

I had ordered some threaded inserts to see how they would pan out for the neck attachment, but despite them being described as steel (two separate suppliers), when they turned up both lots were some sort of cast zinc. I was concerned that the threads might get chewed up easily (I've damaged enough of them over the years) so I decided to stick with my plan from above using a vertical dowel.

I needed to drill the hole for the dowel before routing the truss rod slot (because they intersect) but, in hindsight, it would have been better to delay drilling the screw holes until I could put the neck in position and mark through from the headblock. (Yeah, I know one of them is wonky, but it's oversized and still pointing close enough to the right direction...)

I went around in circles trying to think of a clever way to cut the tenon (router, sliding mitre saw, etc.) but in the end I just used a dovetail saw for the shoulder cuts and the bandsaw for the cheek cuts.

I aimed to angle the shoulders in slightly per the Cumpiano book.

One side is cleaner than the other - I guess I can put whatever time it would have taken me to build a router jig into finnessing the hand cut joint. Time will tell...

I wasn't keen on the headstock outline in the Grellier drawing, so doodled around and came up with something I was happier with that gave a slightly better string angle to the tuners. The shape looked OK on the rosewood headplate blank inside a paper silhouette

So I cheated and used my little CNC router to make a routing / drilling template out of 3mm ply

 

(There are a couple of sets of holes on the treble side as I was still toying with an asymmetric layout.)

I bandsawed a quick-and-dirty dummy headstock out of a piece of scrap 12mm ply to see how the tuning machines fitted and to check for clearance:

The symmetrical arrangement seemed to fit fine and looked OK to me - Decision made.

Jez6345789

Impressive work and way neater than mine going to have to up my linings game the laminate looks awesome. 
Following along 

Misterg

^Thank you! I'm sure there is ample scope for messing things up still

There is much mystery about the process of 'voicing the top' - Carefully paring away wood from the braces followed by tapping the top and listening with a cocked ear and nodding sagely (with apologies to all the proper luthiers...)

I'd read as much as I could about the process, watched umpteen Youtube videos with my best headphones on, but I wasn't really any wiser. A few things struck me:

1) There are very few people that can convincingly describe what they're trying to achieve (e.g. Dana Bourgeois). The Cumpiano book just offers something along the lines of "you'll get the hang of it eventually".

2) A lot of people talking about it on Youtube are only making their 1st or 2nd guitar.

3) None of the major manufacturers seem to pay any attention to the "tap tone" of the top as they carve the braces for a $10,000 custom shop guitar.

4) People make guitars out of all sorts of scrap wood in all sorts of configurations, and *most* of them  actually sound OK at the end of it.

5) The disaster scenario is weakening the braces by carving away too much and having the whole thing fold into a pile of matchwood, or the top belly up after a few months.

My attitude gradually became more pragmatic, and I stopped "needing to know". I decided that as long as I followed the plans, I should end up with something that sounds (at least) OK, and maybe even decent.

Well, the phase of the moon was right, and the mojo was high, so I decided to get on with it.

I was only 'painting by numbers', so my aim was to match the dimensions and shapes in the plans as closely as possible and make it look as neat as I could which got me this:

 

 

 

 

I did try and record audio out of curiosity and for my own future reference. Unfortunately, after I'd recorded the 'before' and started hacking away, my little Zoom recorder died, so the after was recorded with my camera mic.

For those that are interested, here they are - 10 taps in the bridge area while the top was suspended on a finger through the sound hole.

Before:

misterg · Tap tone before carving the braces

After:

misterg · Tap tone after carving the braces

If anyone can offer any insight, I would be very interested. The top is glued on now, so unless it's disastrous, this is how it'll be staying!

WezV

I will listen tomorrow, but there is nothing wrong with doing it by the numbers.  Every factory does it.


Tap tuning will eventually let you get your voice out of any piece of wood.... you don't do it on the first builds to get a good sounding guitar, you do it for the experience those builds will give you for the next

Misterg

WezV said:

I will listen tomorrow

Thank you. Please don't worry about expressing an honest opinion!

nero1701

Thius is stunning work mate, fantastic attention to detail, very inspiring also!!

Misterg

^ Thank you very much indeed - I'm trying my best

Some odd jobs to do before the top can be glued on:

The nice new forstner bit that I had ordered for the tuning machine holes turned up - I think the packaging must have cost more than the bit!

I used it to drill the hole in the head block for the truss rod adjuster - I was originally intending to rout a slot for it once the top had been fitted, but after starting the neck, I had a clearer picture of where the adjuster would end up and realised it could be below the top completely.

After reading various discussions, I decided that only the upper transverse brace and the top ends of the X braces would be fully morticed set into the lining. The lower ends of the X braces will be pared down and clamped between the lining and the top, and everything else was shaved to zero thickness just inside the lining.

Next job was to align the top and mark the ends of the braces and the mortices for them in the lining - The top temporarily lined up on centre and clamped in place:

I was intending to use the rubber strap to wrap when gluing the top, but: a) What I had wasn't anywhere near long enough to wrap round and around the body; and b) it was a PITA to put it on and off when test fitting. I made a couple of spool clamps to help with this process, and having used them, realised how convenient they were and ended up making a couple of dozen to use for the glue up.

I marked the ends of the braces for trimming, and used the same, thin, marking knife that I had used for the back to mark the position of the braces on the linings.

I cut the mortices in the lining the same way as for the back - taking most of the material out with the trim router and finishing up with chisels and a modelling knife. I think I managed to get reasonable fitting joints on both sides (as judged by poking a phone camera into the sound hole:

I did go around with a 0.05mm feeler gauge to find any gaps and then carefully sanded the braces to get everything fitting tightly. I found I also had to finesse the transition between the head block and the sides to get a tight fit - the plane was only taking off dust, but it made a difference.

I finished off the top of the tail block to give reasonably consistent glueing surface to match the linings

The top was trimmed it to a little over the final size, and I did a whole bunch of sanding on the inside of the body.

While I could still see what was going on, I made cauls to fit under the bridge and fingerboard extension for use later in the build:

I had also peered down the rabbit hole of the merits (or otherwise) of 'popsicle' braces (upper transverse graft??)  - the broad, flat brace that is fitted under the fingerboard extension on some guitars - and the alternative 'trapezoidal' (?) brace that some people argue is better.

The plans don't show anything here, so I've assumed that nothing is needed... But just in case somebody tells me at a later date that I should have fitted something, while I could still see what was going on, I cut a piece of spruce ready for use as a trapezoidal brace. I'll just keep this in my back pocket for the moment though.

Erm.. I think that was everything that needed to be done before gluing the top on, so no more excuses...

Misterg

Dearly beloved, we are gathered here today to join together... etc.

Deep breath, glue bottle out...

A flurry of activity later:

I did use the rubber strap, in the end, to fill in between the spool clamps on the lower bout, but this was only a bit of insurance - I'm pretty sure the joint was tight without it.

A quick run around with the trim router, and we have a box!

I was very pleased with that!

drofluf

Looking great!

Roland

Attention to detail is phenomenal. We may never know whether it affects the sound or strength, but you will certainly feel good about it, even though you won’t see it.

Misterg

Roland said:

Attention to detail is phenomenal. We may never know whether it affects the sound or strength, but you will certainly feel good about it, even though you won’t see it.

Thank you! It's a classic case of not knowing what's important, so everything becomes important!

SlopeSoarer

Wow... I've not seen your thread before, what a fascinating read and insight. I'm very envious of your skills, tools, workspace and patience!

Andyjr1515

This remains a splendid build

grappagreen

To go from ‘thinking about it’ to this is just beyond my comprehension.. incredible.

Misterg

Thank you all very much for the kind words^

I took a break from working on the body and carried on working on the headstock:

I tried to plane the headplate blank down to thickness by hand, but had to admit defeat - it was like sawing the proverbial legs off a table - I was just chasing taper around the piece, and rapidly approaching the 2.5mm finished thickness.

So I swallowed my pride and thicknessed it on my CNC router:

I wanted to add a pearl inlay to the headstock - I was originally thinking some sort of block pattern, but then I started wondering if it was possible to cut mother of pearl with the CNC...

It turns out you can, even with a tiny, tiny 0.6mm diameter bit.

This was only going to be a 'look-see' exercise, and I didn't really expect it to work - I had never tried to cut shell before, let alone with a 0.6mm bit, and I was pleasantly surprised that I cut out the whole inlay and about four practice attempts at the recesses for it (in rosewood scraps) without breaking the bit - and these were just "cheap" ones from Amazon. I found this video by Brian  Right (on Youtube) extremely helpful in setting the cutting parameters.

The design actually came out far better than I was  expecting, so I decided to go with it and cut the recess for real in the headplate

The beauty of having it on the CNC is that if I left the work in place, I could re-cut the recess, gradually increasing the size and test-fitting the inlay pieces until they just slipped in:

 

I'd made the recess the same shape as the inlay, just a shade bigger. I have since learned some things about how to modify the shape of the recess (around corners, especially) that makes the pearl easier to fit. (I do regard this whole part as cheating and feel I should apologise to craftsmen everywhere )

Anyway, I glued in the inlay and sanded it back, then tried to glue the headplate to the neck, and messed up:

I wasn't really thinking, and used a soft, cork covered caul to clamp the headplate. This flexed the the unsupported edges of the headplate, causing the middle to belly up. I managed to rescue it by going over it with a household iron until the glue softened (titebond) and re-clamping it. When I trimmed the headstock, the offcuts still seemed to be stuck, so hopefully I've got away with it.

The headplate was trimmed off, square to the neck to form the nut location.

Then the final shape was cut on the router table using the original template...

Followed by drilling the tuning machine holes

It still needs a little bit of filling around the inlay (there are a few pits in the glue), but I'm very pleased with how it came out.

I wasn't intending to fit any binding to the headstock, but may cut a chamfer on the edges. I still haven't decided.

Now I must wrap it in padding while I work on the rest of the neck as I keep banging it on things!

SteveF

That head plate looks fantastic

Misterg

^ Thank you.

A little bit more progress - After giving the body a bit of a sand, I cut into the sides to find the mortice in the head block:

Once I knew where I was, I carefully trimmed the sides and top back and squared up the mortice. One of the neck attachment bolt holes looks a bit wonky (because it is) but they are oversized, so I was hoping things would still line up.

A little bit of work on the tenon on the neck and it fitted in pretty well. Thankfully, the bolt holes all seemed to line up:

Once I knew that the hole spacing was OK, I could make the brass dowel for the neck fixing bolts to thread into:

This is how it will sit inside the neck.

The dowel is a firm-ish fit in the hole inside the heel, so once fitted it's staying there.

To mark the shape of the neck heel, I printed a few sections of the plan at 100% onto overhead projector film (remember them??). The film makes decent templates that are a bit more robust than paper or card.

Once marked, I cut the heel profile with the bandsaw...

...then rough-cut the end profile:

The shape of the bottom of the heel is a 'best guess' as it isn't shown on the plans

After a bit of rough carving, I started the process of adjusting the contact faces of the neck to simultaneously close the joint line, get the neck pointing centrally down the guitar body, and set the correct neck angle.

Initially this was by removing thin slivers with a chisel, and then by 'flossing' the joint with sandpaper. (You pull sandpaper through the joint. This naturally tends to close the joint line, and by the number of times you work each side and varying the direction of pull, you can 'steer' the neck in particular directions.) One tip that helped a lot was to put a strip of reinforced parcel tape on the back of the sandpaper to stop it curling up as it was pulled through the joint.

This was after the first session:

Joint line not too bad;

Neck pointing straight down the body (there are a load of marks near the end of the straightedge that mark my progress!)

Checking the neck angle:

The target I'm ultimately aiming for is that a straight edge resting on top of the frets should just clear the bridge. Unfortunately, neither the frets, fingerboard or bridge exist yet, so I'm working to a calculated clearance of about 2.3mm between a straight edge resting on the neck and the surface of the top at the bridge location.

Not perfect, a tad high, but very much in the ball park.