It occurred to me that once the top is on the violin, I will need to make a new sound post as the repair will have slightly changed the profile of the interior. There are two ways to ensure the correct length of sound post: firstly, you can guess and risk wasting precious sound-post timber, or you can measure the space and cut to size.

My book on violin repairing – which has precious little on repairing cracks! – recommends buying a sound post gauge. Luckily Atria’s book illustrates the principle quite well. And just recently I replaced the windscreen wiper blades on my car…

violin sound post gauge

You see, the spine of the old wiper blades consisted of two thin strips of mild steel about 1 mm thick and 3 mm wide and about 300mm long. I decided to get dangerous with a pair of pliers.

Once I bent the two pieces so they would nestle into each other with opposing ends (already rounded so they won’t scratch the violin timber) I found a piece of clear plastic tubing (fuel line) – although you could use a drinking straw – and bound the two strips together with the tube, and then bent the ends over so they would be easy to grasp and slide the two pieces against each other to make the measurement. I also inserted a small timber wedge from an offcut so as to provide a good friction fit that would retain the measurement while extracting the tool from the F-hole.

And here is the result – a functional sound-post gauge.

violin sound post gauge

And it works well. Happy luthiering :-)

The sides glued up well, and progress continues – after removing the clamps I gave the sides a quick clean-up with sandpaper to remove glue squeeze-out. Titebond liquid hide glue is great to work with, allowing some slip time to get everything lined up ok, but then once it starts to bind it holds well and dries within a few hours.

The mandolin is now starting to look like an instrument, but it is still fairly rough around the edges. The binding provides a decorative border, but also provides additional strength and protection for the joints. I have been quite worried about the gluing process, because hide glue has a use-by date, and I was half-way through before I read the bottle and found it was out of date by six months. Apparently Titebond put a 12 month use-by date on, but liquid hide glue can last 12-18 months. Perhaps I was lucky this time. But if any components fail I will be buying a new bottle forthwith. I could use the hide granules, but that would involve messy use of double boilers and rushing to use it before it cools etc. The liquid glue is very easy to use, is versatile at room temperature and works well.

Anyhow, I had bought some inlay banding strips at the 2008 Canberra Timber and Working With Wood show with a view to their potential for instrument bindings. The banding strips are about 1.5mm thick and about 6mm wide and 1.2metres long. They are easy to use, being flexible enough to do each of the bouts without steam bending, and thin enough to cut easily with a sharp knife.

You’ll have to wait to see how it looks, as they are still taped in position after gluing, but the early indications are good :-)

mandolin bindings

mandolin bindings

The next pictures won’t look much different as I still have to add the bindings for the back/bout interface!

The small round piece of blackwood in the foreground will become the back button, concealing the two pins that help to locate the neck – but more on that tomorrow.

I basically have the back bindings, fitting the fingerboard and some finishing work on the head before fitting it up ready to play – so not long now!

Cheers
Jerry

Having determined from classical guitar construction that the neck can be integral with the neck-block, I set about shaping the neck into its final form.

I began by chiseling the basic form of the heel, then taking the corners off the neck shaft and using a wood rasp and files to form the head junction and basic heel shapes. Then I used the luthiers mini thumb planes to shape the neck to its final form. The orange rubber mat is a cheap non-slip mat from a kitchenware store – it makes a great non-slip surface on which to work timber.

Mandolin neck

I drew around a 20c (Australian) coin to get the curves for the head decoration and cut that out on the hobby band-saw and smoothed it with the drill-mounted ‘Wasp’ belt sander.

Mandolin neck

Then I smoothed the heel curve with the same belt sander and hand finished sanding using 600 grit, then 1500 grit to get a smooth talc-like finish.

Mandolin neck

With one coat of orange shellac
Mandolin neck

The neck is now almost finished
Mandolin neck

Cheers
Jerry

It is time to start roughing out the neck. I selected a solid billet of Queensland maple large enough to do the neck in one piece. Then, using the round-back mandolin as a guide, marked out the block to get a sense of the 3D shape I was after.

Mandolin neck

Queensland maple is very hard timber so I began the roughing out process by making a series of cross cuts, adjusting the height of the saw to follow the contours.

Mandolin neck

Then the waste was removed with a chisel – there is nothing quite like getting the chips flying!

Mandolin neck

The next part in roughing it out, was to rip cut down each side, finishing short of the head.

Mandolin neck

And here is the result so far – a roughed-out neck ready for final contouring.

Mandolin neck

You can read more on the progress so far as follows:
Part 1 – making a start (selecting the timber)
Part 2 – preparing the top
Part 3 – cutting out the back
Part 4- starting the ribs
part 5 – sawing the ribs
part 6 – thinning the ribs
part 7 – kerfing the linings
part 8 – roughing out the neck

Cheers
Jerry

Some more progress, and a solution to a problem. Today I set about sawing the ribs – the sides of the mandolin. The ribs serve little real purpose other than to separate the top plate from the back and define the air cavity between the two. I settled on 50mm wide, 2mm thick and about 600mm long as a starting point. That would leave sufficient timber to scrape it down to remove machining marks and thin enough for steam bending to shape.

I ripped the boards to 50mm – no problem there on the Triton Mk3 saw bench, but the first attempt at resawing to cut thin strips failed with a very nasty and abrupt stop as the thin slat tore off and half disappeared between the saw bench and the blade, trapping the saw blade and bringing the whole process to a rapid stop.

The blade guard prevented kick back, so it was just a technical problem. I unplugged then freed up the saw, and reset it up straigth again as the force of the sudden stop had moved it out of alignment.

I pondered this for a bit and remembered the solution – make a zero clearance sacrificial false table. I had some 3mm MDF (medium density fibreboard) and found a piece about the right size – enough to cover about half the triton saw table. I set the blade to the height I wanted for the cut, then I removed the guard – note if you do that you need to be absolutely focused on your safety. I positioned the MDF above the blade, started the saw, and with one edge braced against the riving knife I lowered the MDF onto the blade, making sure that my hands were well clear of where the blade would cut. I then stopped the saw and there was the false tabletop with zero gap between the saw blade and the MDF. I cut a slot for the fence bolts, then clamped the MDF in position and set the desired gap between the fence and the saw blade.

At that point I replaced the blade guard and made a trial cut in a pine offcut before going back to the precious Tasmanian blackwood, ready to make the thin strips that will eventually become the sides, or ribs of the mandolin.

zero clearance saw table

You can read more on the progress so far as follows:
Part 1 – making a start (selecting the timber)
Part 2 – preparing the top
Part 3 – cutting out the back
Part 4- starting the ribs
part 5 – sawing the ribs

Cheers
Jerry

A few weeks back I bought some padouk, some birdseye maple and some New Guinea silkwood and a couple of blocks of rosewood, at the Canberra “Timber and Working with Wood” show.

Today I have started work on the mandolin. I have a rosewood fingerboard from a broken mandolin, and machine heads from same, but this instrument is basically being built from scratch.

This evening I re-sawed the padouk board so I could book match the timber for the back. Using a jointer I prepared the edges and then thicknessed the boards down until they were identical. I matched up the grain pattern and glued them with hide glue – it’s not vegetarian but it’s the ideal glue for instruments. The board has been clamped and set aside for the glue to set.

I also re-sawed the birdseye maple, which I hope to use for the top – but it is difficult to get a good edge on it for gluing. However, it is reasonably wide, so I may just go for a one-piece top. The mando is designed for traveling and ideally it will fit into a backpack – like the pochette fiddle – it should be close to the shape of a spoon-back mandolin, with a hint of a reverse dimple, so it will actually be more of a guitar shape.

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