Tag: overhaul

Premier Glockenspiel (part 1) (Job No: 1226)

These Premier glockenspiels, like most percussion instruments, are let down by the frame they sit on.  The problem is money.  The manufacturers need to make a profit, because everyone wants a pay rise, whereas the musician wants the best deal possible.  So how do you make a glockenspiel cheap?  You screw your suppliers, and then throw it together as cheaply as possible using a minimum wage workforce.  Only then can the upper managers get new BMW’s.

So when Paul the Porter starts to move the glock around, everything starts to self destruct.

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As can be seen in the diagram above, the weight of the glockenspiel note bars, which are steel, tears the note rail off the base board.

So this is the first thing I look out for when overhauling a glock.

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There are also pins that are missing, but I will get rid of them anyway.

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In the photo above, daylight is visible under the note rail, so I need take it off and see if it can be repaired.  Although the holes for the note pegs had been filled with matchsticks, and there were a lot more holes than needed.  So the likelihood is that I will have to replace them with new note rails.

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As can be seen above, the note rails are beyond repair,  one split trying to remove it from the base.

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In the above picture, I have zoomed in to show the collection of ironmongery holding the note rails to the base.  A pathetic of upholstery and panel pins, with a few of those square twisted nails that were impossible to get out (the reason why I snapped a rail).  Regardless of the type of nail used, the note rail still lifted – this is because nails are exactly the wrong thing to resist a torsional force.  This really obvious; how does a claw hammer work, or pry bar, pincers, etc etc, in fact every tool for removing nails demonstrates where nails are least effective.

Furthermore, because the note rails were made of such low grade softwood, they split really easily, and because the wood is soft, any hole in them will just enlarge.  The replacements I made were out of Oak.

The project continues in 1226: Premier Glock (part 2)

Premier 600 Xylo (part 2 of 2) (Job No: 1187)

This blog post follows on from 1187: Premier 600 Xylo (pt 1)

After all the xylo notes have been varnished, they get tuned and resealed.

The last part of the job is to service the frame.  The note pegs on these Premier xylophones are solid rubber mouldings.  Because they are natural rubber they do age and become brittle, this process can be slowed by removing UV exposure.  Just like people do to prevent sunburn, this can be achieved simply by covering up with a blanket.

I do have a diminishing supply of these note pegs; like most parts I have for obsolete instruments, I strictly control the distribution.  The last few are to be used to repair as many instruments as possible.  They are not to sit on someone else’s shelf just in case they need them for their particular instrument in the future – I deem that selfish, and it won’t happen on my watch!

Premier offered me the moulds to make these parts, however besides storage problems (they are massively heavy), the cost of making the parts was prohibitive.  Essentially the moulds are too old compared to modern techniques.  At some point however, (when funds allow,) I will invest in the equipment I need to make alternative spares using different materials.

Getting back to the Xylophone; besides a few broken note pegs, the frame was in excellent condition, and just needed a thorough clean.  Once the notes were back on, it looks like a new instrument.
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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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Yamaha Vibraphone (Job No: 1200)

If vibraphones are moved around whilst set up, common sense would dictate that the pedal is raised up off the floor, so that it doesn’t drag along the floor and bend the adjustment rod.  Well that’s what this instrument was in for; a demonstration of how rare common sense is.

Furthermore Yamaha vibes have a detachable motor and control unit.  On instruments that live set up, like this one, this is an annoying feature.  The way the motor is attached is fine, that can be tightened in place, but the control unit just hooks over the note rail.  So whilst it was in my hands, I was asked to permanently fix it to the instrument.

However, as I was moving the instrument it became apparent that something else was wrong.

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The drawing above shows Paul the Porter pushing an instrument along, about to enter a room.  The force is being applied to the top of the instrument, however the wheels running along the floor have resistance in the opposite direction.  As Paul wheels the instrument through the door and consequently over the door tread, the resistive force increases further in a shock loading.  This is why instruments in general, including this vibraphone end up wobbling.

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As can be seen from the drawing above the movement on the instrument is greater at the top than the bottom.  The top frame, which is the note bed, is therefore being pulled apart.

The only way to resolve this situation, is to continue the destruction, in a controlled manner, until the weak link is exposed.

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On Yamaha vibraphones, as can be seem above, everything is pegged and glued together.  Which is fine, if it is designed and assembled correctly.  However if it is not, this self destruction is exactly what happens as the badly designed frame starts wobbling and all the screws work loose.

There is not much I can do within the remit of the job.  Ultimately, I would have to extensively modify the instrument making complete new sections.  However I can’t return an instrument that I can see is falling apart, so everything was glued and clamped back together.

Straightening the connecting rod between pedal and damper bar was easy.  For the speed controller I just made a little plate that went on the underside of the unit and hooked under the note rail.  Both of which I forgot to photograph.

Bergerault Pedal Glock (Job No: 1202)

Bergerault have secured a place in my top ten bad designs with this pedal glockenspiel.  In order to minimise the number of removable parts and create a glock that is really quick and easy to assemble, they have this “great” idea of being able to adjust the length of the pedal.
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In itself this is a stupid thing to do, but they were forced to do so in order to make the rest of the design work.

The problem is that the legs fold out, and are secured in place first (albeit with diagonal braces that are also badly designed), and then the bottom bar is put in afterwards.  The bottom bar sits on little pins at either ends to enable it to rotate and thus becomes the pedal.  These pins are the problem, the bar has to be reduced in length to get it over,  then lengthened to “secure” it in place.

As a finishing touch, the method of holding the bottom/pedal bar at its full length is a throw back to the 1970’s, a wing screw and a nut.  I remember when certain makes of cymbal stand first started using nylon inserts, now they all do and with good reason as any percussionist will agree, finally something that consistently works.

The end result of all these stupefyingly bad design errors is an instrument that collapses as it is being wheeled about.

The next problem on the list are the connecting rods to the damper mechanism.  At the bottom they hook over little nylon wheels on the pedal.

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These just become detached while you wheel it about making an irritating noise and becoming hooked on things and being bent, except when they don’t become detached and then get bent when the instrument collapses.

The real problem with these rods is at the other end, where a leather belt is used to connect them to the damper bar.

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Yes that is a leather belt.  The photo is actually off another instrument.  This glock had a variety of materials including string, gaffa tape and cable ties.  Leather needs to be cared for, otherwise it dries out and degrades.  The buckles just rattle.

There are a lot more design issues with this glockenspiel, but those three were the problems on this instrument.  However it is not all bad, the notes do sound really good, and after all that is the most important part of an instrument.  It is just a shame that the rest of it is, well, basically shit.

So what did I do?  In reverse order: 
I took the damper mechanism out and sewed two webbing loops to replace the missing leather straps, and eliminate the rattling buckles.  There is no need for the length of these loops to be adjustable, and the webbing won’t degrade as quickly (3 years to 30+ years).

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One of the nylon wheels on the damper pedal was missing, so I made two new ones that prevent the connecting rods from coming off.  This instrument is never folded down.

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I made an additional bottom bar that fits behind the pedal bar.  This secures the legs in one position; they can neither be pushed in or pulled outwards.

Finally I put on better castors.
 

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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)

1.1/2″ Tubular Bell (part 1) (Job No: 1206)

Tubular bells, like most percussion instruments are simplicity themselves; they are just a tube of brass normally reinforced at the top with a cap.  However, like most percussion instruments, they are little understood, and the simplicity of design belies the challenges faced by an instrument maker to deliver a good sounding instrument.  If it’s just a tube with a lid, how will I know whether it will sound good, and what can I do if it sounds rubbish?

I have yet to be convinced by any claims that manufacturers make in marketing about their ‘fantastic tubular bells.  What they fail to publish, are reasoned arguments, supported by research and data.  However they are not writing publications for me to read, they are writing to sell instruments to musicians who go on to accept their statements as fact [suckers!?]

So what is the solution?  Research.  Everything I do, I document; it is from this accumulation of data and observations that I gain a deeper understanding of all the instruments I work on.  Furthermore, it provides the platform from which hypothetical improvements are made and subsequently tested.  By improvements I mean manipulating an instrument to improve its musical timbre.

To make a set of tubular bells by mass production, a saw to cut the tube to a predetermined length is needed, and a drilling machine to drill the holes in a set position.  There may or may not be a secondary tube for the cordage to pass through.  To make the caps, a computer operated lathe will be used.  The caps are then pushed into the tube using pneumatic rams.  Polish and chrome; job done.  One musical instrument made!

My method of making tubular bells is very similar.  Starting with a suitable length of stock tube and referencing my accumulated data, the tube is cut a little longer than the longest bell of that pitch that I have ever seen.  Why?

The first reason is that no two lengths of brass are identical.  The assumption that materials are completely uniform is a fundamental flaw in the concept of mass produced musical instruments.

The second reason is to accumulate more data.  Because I can only get two, possibly three bells out of a length of tube anyway, I cut them as long as possible.  The result for me is two or three times more data is acquired as I raise the bell to pitch by shortening the tube.  The extra length also provides opportunities to experiment and still be able to make a bell at the correct pitch.

Now I have an oversized tube I clean up one end clean up one end.  This has to be done by hand, because I don’t have the room for a lathe big enough to take a tubular bell (unsurprisingly), so it takes a me a lot longer versus factory.
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Next I have to set the drill up so that I can cut the holes for the note cord.  Just setting the drill correctly takes time, which is why making one bell is always more expensive than several.
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After I have the holes drilled, I remove all the sharp edges, making them rounded in cross section.  This prevents the metal from slicing through the cord.  It is this attention to detail that takes me time, but saves my customers time and frustration.
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Before the cap goes in, I stamp the tube with the pitch of the bell rather than the cap which is the playing surface.  In several instances, my customers accumulate a complete set of bells over many years, and I want to give them consistency of design, so I have a little pattern to get all the stamps in the right place.

What I never get is perfection.  It’s bloody hard to get the stamp perfect, I used to get moaned at by my boss when I worked at a shop for wonky letters.  Over a decade later, I still find it impossibly difficult and it still upsets me when they are not right, but I’m better at living with the disappointment and view it as a mark of humanity as opposed to the machine.
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Now the tube is done, I make the cap.  This is turned in the lathe.
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In the photo, I am checking the angle at which the chamfer is cut.

The cap is made to a sliding fit into the tube.  The cap is solid brass, if it has to be forced into the tube it is the tube that will expand.  This expansion of the tube creates internal stresses and makes the brass less ductile, and it is the reason why the tubes split at that point.  In my view this is another indication of the embarrassing lack of knowledge displayed by the major manufacturers!

The cap is then bonded into the tube, I paint the letter stamp, and everything is left to settle prior to tuning.
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This blog post continues in 1206: 1.1/2″ Tubular bell (part 2)

Glockenspiel notes (Job No: 1220)

There are actually two glockenspiels in the workshop requiring new notes, so obviously I make them all at the same time.
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The main difficulty I have is finding material of the correct thickness; a lot of old glocks use imperially sized materials, whereas metal now has to be sold in metric sizes to conform to stupid government legislation brought in those self serving idiots in Westminster. Now I can’t buy 1 inch metal stock, but sometimes after searching I can find 25.4mm stock. Anyway, that is a chore, and actually takes time to go through all my stock of metal looking for a suitable piece, because not forgetting it also has to ring.

I was lucky with one of the notes, I found something that matched, but for the main job, I could only match the thickness, not the width. In the photo you can see a wide piece of metal at the back; I have to cut it down it’s length making it 1 inch wide, then dress the edge ensuring that the sides are parallel. After that, it is easy to drill a hole and cut to length!
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At this stage I tune the note bars around 10 cents sharp, to allow for finishing and polishing, which detunes the bars. This is part of the job which takes time.

The project continues in 1220: Glock notes (part 2)

Tam Tam frames (Job No: 1203)

I was asked to make a pair of tam tam frames, so after going to the venue to measure the instruments and the environment where they are to be used (stage risers, door width, etc) I’m ready to start.

The design they want is really simple, two big square frames on wheels, so first I cut all the material to make two big squares.

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Which were welded together, the pile of offcuts in the photo above were used as little braces to add strength and rigidity to the corners of what are two very big free standing square frames.  Everything I make is guaranteed for the rest of my life; these subtle additions to designs is how and why I have the confidence to do that.

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There are subtleties that no one will ever see; the bottom of the square is stronger than the top, which is in turn stronger than the sides, this keeps the weight down, without losing structural integrity where it is needed.

The tam tams have to hang from something, and they have varying diameters and cord lengths, so I make more hooks to hang them from,

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and weld them into place.

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The last part of fabrication is to make the subframe that has the wheels, and clean it all up.  Then it drop them down to the powder coaters.

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Invariably, when I get stuff back from the powder coaters, then the rebuilding of the instrument starts which can be a lengthy process.  It is a nice break therefore to get frames back that just need the casters bolted on, and they are ready for delivery.  Job done.

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Premier 751 Vibraphone (Job No: 1179)

A Premier 751 vibraphone in to have a service.  Particular issues are inconsistent damping and note sustain.

A quick look at the frame revealed no major issues, however the fan shafts were very noisy, so I started here.
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The Premier 751 Vibe is no longer made, so all spare parts are now obsolete.  When Premier stopped making this vibraphone, I was invited over to buy all the remaining spares.  Therefore if I don’t have it, then its unlikely that anyone else will – unless of course that they don’t do many of these very common vibes!

One of the problems with the fan shafts being noisy is the central bearing (pictured above).  In order to get this on the fan shaft (because it can’t go past the butterflies), the top of the bearing is sliced through, therefore it loses structural rigidity.  This becomes a real problem when it is forced into the resonators; forced because they were made a little bit too long, so they have to be bent to get them in.  The same thing happens at the low end, but there the bearing doesn’t have to be cut.  This bend creates a pinch point on the rotating shaft, and an ambiguity in positioning, this is where the noise comes from.  Thankfully because these spare have run out, I now have no option but to make a replacement, which means that I may as well solve the problem permanently.

First on the list of improvements is better material, I use a low friction nylon.  I would have used PTFE, but in
this instance it needs to hold a thread.  The originals are moulded plastic, so they start with a structure and add bits to the design for strength, because mine are cut from a sheet of material, I start with a block and remove bits where needed, but there is still a big increase in mass.  Therefore mine are way stronger than they need to be (which means that they should never need changing).

There is of course another benefit.  These bearings are now made when needed, and modified so that the holes are all aligned correctly so that the fan shaft runs true.  They are essentially matched sets.

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The central bearing is made in two halves and held together with machine screws, but all of the bearings have a little hole for oiling.  This is the complete opposite to progress – I have copied a concept used on vibes made in the 1930’s in the UK (where we invented engineering and are still unsurpassed), all I have done is used modern materials.

The only problem is that they don’t fit!  I went through several designs a few years ago, trying to make them so that would go in the space available, but they all failed.  Since then, I decided simply to increase the available space.  This means cutting the resonator tubes, and unlike every other time I have seen a tube modified, I remove the tubes from the set to work on them and not damage all the others.  It’s a no brainer!

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As can be seen above, I have increased the chord length of the cut out, and its depth.