Sunday, May 31, 2009

Jill's Mandolin VII

Well, the back of Jill’s mandolin has been bound and the neck fitted: you can see the sequence below.
A relatively large mortise is routed into the body of the mandolin using a router with a template follower. A matching tenon is cut on the neck: it takes a good few hours of fettling to get the neck perfectly aligned. Once the neck is in place a wedge, which supports the end of the fingerboard is fitted.

Next on is the fingerboard that you saw prepared in the previous entry. I like to plane the fingerboard to its final thickness and profile once it’s been glued to the neck. The dots go in next and then the fingerboard can be fretted.

The frets have to be carefully filed so that they are all level with each other. This process leaves a slight flat spot on the top of the frets which are then restored back to a curved crown using specialist files.

Now I start shaping the neck, the first few steps look a bit barbaric! The fine work starts tomorrow!

You may have wondered what’s happened to the Blackwood pair; Morgan came over for a couple of hours earlier today, to discuss the bridge design; so that should all unfold over the next week or so. More on that later.....

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Sunday, May 17, 2009

Jill's Mandolin VI

I’ve been working on the purflings and bindings for Jill’s mandolin, so I thought that I’d go through the process with you. Once the soundboard, back and sides have been glued together and cleaned up, a rebate has to be cut around the entire instrument to take the purflings and bindings. You can see why the linings are so important, as the joint between soundboard, back and sides is completely cut away. Although the router cuts an accurate rebate, an instrument such as my twin-point mandolin needs a bit of fettling by hand. You change the width of the rebate by changing the diameter of the bearing.

With the rebate cut the first layer of thin (0.9mm) black/white/black purfling goes on; I use map pins to hold this firmly in place whilst the glue dries. Once dry, the second layer, a red veneer and another thin black/white/black purfling goes on. As there is no longer any room for pins, masking tape is used to hold this second layer in place. The purfling at the points has to be very carefully mitred.

Once the last layer of purfling has dried, the bindings go on. I always use wood for the bindings and they tend to be about 2.5mm thick, so they have to be bent on the bending iron, just like the sides. I’m using Claro walnut here to match the head overlay. Mmmm maple and walnut my favourite ice-cream! The bindings are held in place, whilst the glue sets, with cloth tape that is stretched around the instrument. This piece of cloth tape is 50 metres long and on a guitar all of that will be used up!

The whole purfling process takes quite awhile, around the soundboard there are 16 separate pieces of wood and it took me 10 sessions to glue them all on, allowing about 5 hours for the glue to dry each time. And of course once the front is done, turn it over and do the back!

One of things that I have been doing in parallel to the purfling is preparing the fingerboard. I use a modified (by me: notice the toggle clamps to hold the board firmly) Stewart MacDonald jig for cutting the fret slots. StewMac tools and jigs tend to be expensive but they are very well designed and made and should last “forever”!

Once the fret slots are cut, I drill holes in the edge of the fingerboard for position markers: I like to use nickel silver wire which matches the fret wire. I also like to drill pilot holes for the dots on the front of the board. It’s so much easier to mark out accurately before the board is glued. Nothing worse than a wonky dot! These Incra rulers are excellent for marking out: thoroughly recommended!

Now let’s do the rest of the purfling on the back.........................

P.S. You may remember that in a past post I mentioned my friend Mandolin Jack Flatt? He has a great new CD out available via CD Baby

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Thursday, May 07, 2009

Jill's Mandolin V

As you saw in the previous post the two Blackwood instruments are now being finished. An hour or so is spent on each one and the remainder of the day on Jill’s mandolin.
You can see the bracing of the soundboard and back. The X-bracing works very well on the back, giving it a graceful arch. I’ve always used X-bracing on mandolin backs it seems to make more sense on a small, almost round body shape, compared to transverse bracing.

Before the soundboard and back are glued on to the sides, small housing joints are cut into the linings to take and support the braces.
Next stage, glue them together!

How do they do it?
I’m always surprised when you see cheap electric guitars, how on Earth can they make them so cheap? Raw materials, hardware, labour costs, factory up keep, shipping, dealer’s mark-up etc.
I’ve been commissioned to build an ergonomic electric guitar later in the year and have just bought some prime mahogany for it. Below you can what £100 worth of neck and body blank looks like. So a guitar for under £100! How do they do it?