Tag: 1214

Bergerault Vibraphone (part 4) (Job No: 1214)

This post continues on from 1214: Bergerault vibe (part 3) and started with 1214: Bergerault vibe (part 1)

The inner two note rails are only supported at the high end of the vibraphone by a metal bracket.  Onto this bracket is also mounted the motor.
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Because I have increased the depth of the two outer rails this bracket no longer fits.
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So I just modified the design a little, and welded new outer supports in.  Now it will also be stronger, and certainly welding is a lot stronger than brazing which is how Bergerault make their instruments.  Welding is fusing two like metals together, so essentially it becomes one piece, whereas brazing uses a different metal to join the two elements, like glueing them together.
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Now this bracket is on, the top frame is rigid, all it needs is the motor unit.  Then I can put the legs on the vibe, and put the notes back on.
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It’s both satisfying and dissatisfying to see it all finished.  On the one hand it is good to see a finished instrument, especially when the job has been so involved.  On the other hand it looks just the same as it did when it came in, which is the point, but still I can’t really see any evidence of all the work I have done.

Bergerault Vibraphone (part 3) (Job No: 1214)

This post continues on from 1214 Bergerault vibe (part 2) and starts with
1214: Bergerault vibe (part 1)

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The above image shows my progress with the Bergerault vibraphone over the last three days, from the left; prime, undercoat, top coat.

This is the moment, before I put the new note rails into the instrument, to sort out any problems with the inner two note rails.

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Unsurprisingly, these rails were also loose.  Like the original outer rails, these also have a single tenon towards upper side of the rail.  This is supplement with a tiny bracket at the bottom.

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As Paul the Porter pushes the instrument at the top, there is greater friction at the wheels making the instrument rock from side to side.  The leverage exerted by the very long rails on four octave instruments is enough to break open a single tenon joint, especially if it is located at either end (top or bottom).  Again this is a design flaw; a demonstration of a lack of knowledge, forethought, and expertise.
I go to museums and see objects made literally hundreds of years ago that demonstrate the type of joint needed to resist a particular force.

Once the glue is dry on the inner note rails, I can then glue in the outer rails.

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If you look very closely at this end of the outer note rails, there are two holes.  This is an idea that I ripped off those museum pieces.  It’s called a pegged tenon joint.  Back in the day, they would have used a wooden peg, today I use a big screw.  This screw ensures that the tenon cannot be pulled out, and massively increases the strength of the joint – why wouldn’t I do it, it took less than five minutes.

At the end of the day, I will remove the clamps and do one final coat of paint so that it will be finished for the final assembly.

This post continues in 1214: Bergerault vibe (part 4)

Bergerault Vibraphone (part 2) (Job No: 1214)

This post continues on from 1214: bergerault vibraphone (part 1)

The timber I bought is European Oak.  I could have also used Ash, but that was not available.  Both are known for their structural rigidity as opposed to the original timber, which is hidden behind a plastic veneer, but looks to be African Mahogany which is a cheap easy to use timber, which is not known for its strength.

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After planing the timbers to size, I marked off the length and angles, to duplicate the existing note rails.

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Because I am doubling the depth of the note rail, I put a double tennon at the ends to go into the end boards.  This will massively increase the overall strength of the instrument.  These outer rails are the only joints that hold the whole instrument together, so they must be good (unlike how they were).

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Pictured above are the note rails with double tennons roughed out ready for the mortices to be dug.

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Once All the new mortices were dug, I ended the day with a dry assembly to expose any problems.

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Bergerault Vibraphone (part 1) (Job No: 1214)

These Bergerault four octave vibraphones are massive!  Even though vibe notes are made from aluminium, that doesn’t make them light, in fact the opposite is the case.  Percussion instruments are heavy, but vibraphones are particularly so.

The reason for this vibraphone coming into my workshop was because the butterflies in the resonators were hitting the underside of the note bars.  When I went to collect it, I spotted the probably cause, and verified it with my straight edge once back at base.

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Because the vibraphone is so big, it is hard to get it all in the photo and still see the issue when the notes are on, but after I have removed the notes it can be clearly seen that the instrument sags in the middle.

The first job is to remove the base frame, which are attached to the end boards.  It was at this stage that I noticed another potential problem:

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The little blocks that Bergerault have put in to hold the resonators, are wonky.  I will have to investigate this, because I also noticed that the resonators didn’t hang straight, they were pulled in at the bottom.  I suspect that this is a Bergerault design error, but it just seemed wrong to me.

Once the legs are off, I can now remove the High End board using the motor support bracket to hold the note rails.
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Next the motor and control unit are removed.  I will take the opportunity to improve this whole area which at the moment looks like a dogs dinner.

Finally the offending rails can now be removed from the Low End Board.  Classic understatement, I had to sit down and take a breather after I finally got them out!
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Now I am ready to make some replacement rails – time to go shopping for timber.

The story continues in 1214: Bergerault vibraphone (part 2)