I first thought of the idea of a 2-register John Smith Busker Organ in 2009.  Two years later I experimented with the idea, made up a working prototype slider unit, and published an article about it on my web site and Busker Forum.  See my original article.

For various reasons, I wasn't able to build a working organ at the time, using my revolutionary idea, because it meant starting a new build from scratch; and I didn't have the time.

I encouraged other people to take up my idea, but I don't know anybody who has built a 2-register organ - until now!  Chris Richmond has just built such an organ, and he has very kindly submitted this article to explain it in detail.  I must say he has made an absolutely  marvellous job of it, and it is difficult to believe that behind this facade is a John Smith Busker Organ!

Yes this IS a John Smith Busker Organ!  The 2 pipe ranks at the side are dummies, but all the rest are working pipes.

In late October, I visited a local firework display in my home County of Norfolk. For several years now, a regular feature of the event had been the 68-key Bursens street organ owned by Teddie Cushing, son of the late George Cushing who founded the nearby Thursford Collection. This particular organ has always had a special place in my heart after seeing it at numerous events throughout Norfolk during my childhood. The bright lights, animated wooden figures and the colourful sounds that emanted from it fascinated me each time I saw it.

Teddie Cushing's 68-Key organ built by a then-elderly Arthur Bursens in the 1970s.

After carefully studying the plans and watching the provided DVD, I soon realised that there was the potential to enhance this simple machine into something a little more elaborate. I started sketching-up ideas for decoration inspired by the style of that particular Bursens organ, and so I began to develop a plywood front, which would almost represent a scaled-down version of it.

The rear of the large front panel of my Busker organ. Note the two ranks of "dummy" pipes. These will form a decorative screen with the bass pipes mounted behind.

As the construction of my own Busker developed, I eventually got to a point where I could start experimenting with this idea and created a very primitive slider mechanism, which was split into two seperate sliders to see whether two pipes could sound at once (I do love the sound of a good bourdon celeste- something which the Bursens organ had.) This slider was never a success. Apart from it being rather crude with several air leaks, Melvyn soon informed me that with the exception of the top few melody pipes, there is not sufficient air travelling through the hole in the paper to sound two pipes at once.

The very crude "Slider MkI", which featured two independently-controlled sliders, was unsuccessful.

However, one major flaw was that the pipe shelf I had made was too thin and would bow slightly in the middle. Because everything was still at the experimental stage, the pipes leading from the tracker bar were cut long, and would cause the bowed centre of the pipe shelf to "bounce" as the pipes came into contact with the reservoir.

The three main parts of "Slider MkII", which appeared to work, but wasn't the neatest or most robust design. From top: Pipe shelf (with strengthening baton), hardboard slider, bottom block with drilled channels.

In my collection of wood was a pine shelf of about 15mm in depth and 68mm in width. Now, I know pine isn't perhaps the best wood due to its porous nature, but I was determined to give it a go (this became Slider MkIII) I marked up all the holes for the pipes using "Slider MkII" as a template. Also in my collection was a thin piece of hardboard with a lovely veneer-effect coating on one side, which had a rather slippery feel, and was resistant to paint or anything else that made contact with it. Despite hardboard also not being ideal, the piece was the exact same width as the piece of pine- almost like they were destined to fit together! The majority of the hardboard became the slider unit. This had to be cut at such a size that the ends would only slide one hole's width along AND not foul the holes of the adjacent accompaniment pipes. It is also important to leave an area which will protrude from the slider unit so that a "stop action" can be attached to it in order to operate the slider from the outside of the organ. Please note that the length of the pipe shelf was cut to fit within the original specifications of the Busker organ plans.

To help enclose the sliding hardboard part, a pair of wooden batons were glued to the edges along the lengths of the pine pipe shelf. The critical space for the depth of the slider was measured quite simply by setting the pine shelf on top of the hardboard and clamping the batons to it. Once the glue was dry, the whole shelf assembly was cut to size. Obviously the batons would only be required to surround the space covered by the slider. However, for neatness, the frontward baton was left complete along the entire length of the pipe shelf. The rear had to be cut to allow the space for the moving con-rods and reservoir transfer pipe.

A representative exploded drawing of the three main components of the slider assembly.
(Click for larger view)

In order to create the slider assembly, I used the remainder of the hardboard to "build-up" the area surrounding the sliding part and the rest of the pipe shelf. The hardboard was then covered with a paper gasket to allow for the tiniest bit of clearance to enable the slider to slide without having too much air leaking from it.

This was then topped with a piece of plywood cut to the exact same size as the pine shelf/baton assembly and sanded down flush. At this point, I marked the holes out onto the plywood using "Slider MkII" as a template so that the holes would line up and began to drill-out the vertical holes. For the accompaniment pipes, I drilled 6mm holes right the way through the assembly to allow for pipe connections above and below the pipe shelf (the brass inserts from the pipes themselves slot down into the holes, while the brass inserts from the plastic tubing slots in from underneath).

For the melody pipes, I drilled down into the pipe shelf about three-quarters of the way to the bottom, forming a blanked-off hole. 2 rows of 9 holes need to be drilled to enable two ranks of pipes. It is an idea to screw the whole assembly together with the slider in place at one end of its travel and drill one rank of holes, then sliding it to the other end of its travel, re-screwing it all together and then drilling the second rank of holes.

The resulting screw holes through the slider give an indication of the travelling area of the slider and an enlarged channel should be filed between the holes allowing for slider travel as well as adjusting the tension of the slider and more importantly, keeping the unit assembled. I also added screws to the areas of the accompaniment pipes, which hold the assembly together, eliminating the need for glue so that the unit can be dismantled easily and without mess and damage.

Unlike "Slider MkII" where the holes for the plastic tubing were all drilled underneath the bottom block, I decided to drill the holes for the 9 melody pipes to the rear of the assembly (through the rear baton). I carefully marked out the holes using a set-square to ensure the channels would align with the top holes and drilled 6mm holes through the side of the assembly until the drill bit had reached the furthest hole towards the front of the unit.

Once all holes had been cut, I then cleared the channels and soaked them in water/PVA glue mix to seal them. One thing I did learn from this is not to over-do it, as the wood can swell and the remaining mix dries up and shrinks the holes a bit. I then re-drilled the holes to 6mm , as it had a detrimental effect on the airflow to the pipes.

I then plugged the holes in the side of the block with short lengths of 6mm brass tubing to attach to the plastic tubes leading from the tracker bar (which would be considerably shorter in length and wouldn't foul the movement of the reservoir as they did when entering from underneath in "Slider MkII". The tubes for the accompaniment pipes were still connected from underneath the pipe shelf, as if they were connected from the rear, the tubing would foul the action of the con-rods and also clash with the positioning of the reservoir/bellows transfer pipe.

Prior to the final assembly of the slider unit, it was essential to sand down all sliding parts with very fine wet & dry paper to reduce as much friction as possible on the sliding surfaces. To assist the hardboard slider, I coated the previously untreated underside with a couple of coats of gloss spray paint to smoothen it up. It is worth letting this dry thoroughly for at least a couple of days to prevent it sticking once inside, then abrade it with the fine wet & dry paper when it has dried solid.

Once the whole unit was assembled, the centre screws were tightened hard before slacking them off slightly. this is to help eliminate any bows in the plywood or hardboard slider part (of which there was some warpage apparent, which leaked a tiny amount of air at the outer edges).

Once the unit was assembled and installed, the top holes for the melody pipes pipes were fitted with 6mm brass tube inserts and the pipes pushed onto them.

During the testing of the unit, there was one apparent problem, which mystified me at first... If your slider unit is as compact in width as mine, there isn't much space between the two ranks of melody pipes- especially between the larger pipes, where the lack of room actually inhibits the voicing of the pipe. Melvyn suggested turning the rearmost rank of pipes to face backwards, which completely solved this problem!

The whole unit was mounted half way up the front of the organ on blocks attached to the sides of the organ Because my design was not bound by height, the largest pipes stick up a considerable distance above the top of the pressure box. The unit is fixed by screws entering the ends of the pipe shelf through the sides of the organ. Once the organ front is removed, the pipe shelf/slider assembly is easily removed and can fold down whilst still attached to the plastic tubing, giving access to the pressure box take-up spool and idler wheels.

"Slider MkIII" removed from its shelf showing the plastic tube connections gaining access to the drive wheels. The stop action mechanism can be seen towards the right. Metal washers are glued to the hardboard slider to prevent wear and provide strength.

So, after a few months of experimentation and determination, I can now say that I am the first person to successfully construct a Busker organ with two registers and 29 pipes!

Unfortunately Melvyn never did fit his slider unit back into his organ.  However, I thank him greatly for inspiring me to develop his idea and for his helpful advice throughout the process.

The front of my Busker organ with all pipes now in position. Notice how the left and right ranks of "dummy" pipes compliment the bass pipes behind and gives the instrument the impression that it is larger than is actually is. The elaborate patterns are actually waterslide transfers carefully traced on the computer from original photographs of the Bursens organ on which the front is based. I'm no wood carver, so the textures on the scrollwork were inscribed with an electronic engravers pen.

The latest addition - A 'Mockenspiel'!

I have recorded a video, which can be seen here.

Chris Richmond.