Acoustic guitar repair London: Gibson 1966 LG-0 (Hot Rod)





Here is an interesting project recently taken in by the workshop: a Gibson LG-O made in 1966

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This is an all Mahogany guitar: Mahogany soundboard, back, ribs and neck. This guitar was a budget instrument at the time of manufacture and sold at an affordable price as an entry-level model. The guitar has a slim neck which measures 1 9/16’’ at the nut and joins the body at the 14th fret.

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The Bridge

In 1962 with many thousands of the LG-O sold Gibson decided to exchange the standard rectangular Rosewood bridge for a plastic “belly above” type. This plastic moulded version was held in place by 4 screws that attached from under the soundboard up into the base of the bridge. This was done for ease of removal when dealing with replacements. This was upgraded in 1968 with a Rosewood replacement which included an adjustable saddle.

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 The Soundboard

The soundboard is ladder-braced with 5 lateral braces across its width. This type of bracing gives a distinctive tone that is indicative of the old acoustic Blues sounds of the 1930s. However, this system lacks structural strength and over time the soundboard can become bulged and distorted with string tension. The over large bridge-plate can exasperate the problem as these where generally made of softwood which also offered little structural strength. The LG-O was discontinued in 1974.



The Brief

Our Brief in this instance was to remove the internal ladder bracing, replace with a scalloped X brace system to give the guitar a more balanced tone and to accentuate the bass tone.

To upgrade the bridge-plate and to make and fit a Rosewood replacement bridge.



Removing the Back

In order to gain easy access to the internal bracing it will be necessary to remove the back.

This LG-O does not have an edge binding around its back outline. Therefore, a thin pallet knife is slipped between the back and the end block to start the separation. Once started a Japanese saw is used to precisely cut through the inner lining. Because of the saw’s thin blade and unique cutting motion very little material is lost during this process.

 

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Once the back is removed the simplistic ladder-brace system is revealed. You will notice that a brace and the bridge-plate are missing. I believe these became loose and subsequently lost years before. Their footprints are still visible.

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Rosewood Bridge-Plate

The remaining braces are easily removed and the internal face of the soundboard is prepped in readiness for its upgrade. An Indian Rosewood bridge-plate is made up and fitted. Rosewood is the workshop’s prefered material for bridge-plate replacement because of its strength to thickness ratio.

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Go-bars are a very handy and simple way to fit bridge-plates and braces. They are made from flexible timbers that allows pressure to be applied where needed whilst glue is drying.

The Bracing System

The bracing system is made up and glued into place piece by piece.

Each brace is made from 1/4 sawn straight-grained spruce individually scalloped.

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 Gluing the Back

Once the bracing system is completed the back is cleaned up and glued into place

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A replica of the plastic bridge is made up out of Brazilian Rosewood and fitted

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The Set-Up

The frets are showing some wear. They are honed and re-profiled and the truss-rod is adjusted.

The guitar is strung up and tested.

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 Conclusion

I’m happy to report that the finished upgrade turned out very well. The guitar has a sweet sound with a good balance. It has a warmth and depth to the bass with sweet mids and trebles. It likes to be picked as well as strummed and I suspect that it will record very nicely and with a small body guitar that’s all you can really ask for.

Full size photos available here on Flickr





Guitar Restoration: Vintage Michigan Jazz Guitar


Stan Alexander from The Darts came into the workshop over the weekend. He called to collect his Michigan Jazz guitar which has been restored.

The guitar has been in Stan’s possession for many years and remained stored in his attic for several decades.

It was in a bad way:

The neck had parted company with the body

The soundboard and back were both loose

The internal bass bars* were cracked and loose

The ribs were split and cracked

The fingerboard inlays were beginning to lift and curl up

The end on the neck was split and cracked

The machine heads weren’t working

The bridge was missing

All in all it was a sad case. However, over the course of a few weeks work commenced on the old jazz veteran and the guitar was put back together piece by piece.

Firstly, to get to the loose and cracked bass bars*  the soundboard was removed, the bass bars repaired, cleaned up and re-glued. A temporary mould was made up using stiff cardboard. This was a precautionary measure to ensure that the ribs retained their shape.
*Bass bars are the internal strutting that help give the soundboard its stiffness and is partially responsible for the “acoustic” sound of the guitar.

With the soundboard removed the repair to the ribs was made so much easier. The splits were repaired and reinforced from the inside.

The back was then re-glued to the ribs.

The soundboard re-fitted to the ribs.

Once the body was whole again the edge bindings were cleaned up and stained where necessary.

The neck was re-aligned and re-glued to the body.

The splits and misaligned holes at the end of the fingerboard repaired and plugged

The whole of the completed body work was cleaned and polished.

The new machine heads and bridge fitted.

The pick-up and electrics were overhauled and re-installed

The guitar was strung up with heavy gauge jazz strings.

The guitar played like a dream. It had a low action without any buzzing on the frets, it intonated very well and sounded great acoustically, just what you would expect from a vintage jazz guitar. And when it was plugged in to an amp it sounded fantastic.

Stan was delighted and used the old vintage jazzer at a jazz gig that evening.

Job done!