My 26-Note Universal Organ

by Anthony Ashe

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Some time ago I read an article in the "Model Engineer "magazine about constructing a Busker organ using plans by John Smith. I spent most of my working life in engineering and in my spare time have made various clocks and a working scale Steam Traction Engine.  I am now retired but an active member of the Wirral Model Engineering Society and have helped with the construction of 5" raised and 71/4" ground level tracks in a local park where the club members run their locos and offer rides to the public.

I have always been interested in Fairground type organs I and thought one would be useful, amongst other things, to entertain the queue waiting for rides. Working at 8 W.G. it would not pose the safety issues of high pressure boilers and the only public liability would be the effect on the ears which I have not found a problem, "What's that you say"?

I consider myself a man of many parts, some of which are still in working order but have never contemplated making an organ until I read the aforementioned article, so I purchased a copy of John Smiths plans for the 26-Note Universal Organ. When I started in engineering I used to be asked to make things from sketches on 'Woodbine' packets so I considered following John's plans a possibility.

Taking the dog down to the beach for a walk one day I had the good fortune to park the car by a residential home which had a skip outside. As the dog and I got out of the car a builder emerged from the home with some large planks of seasoned pine which he dumped in the skip. He said that I could have what I wanted so the planks were transferred to my car and the decision was made to start on the Organ.

I next ordered a tuning meter, 26-note test roll, 6'x4' sheet of 1/4" birch ply, 6'x4' sheet of tempered hardboard, large bottle of PVA glue, leather for the bellows, valves and puffs, boxes of twin threaded woodscrews, 1.0 mm and 0.5 mm sheets of cardboard, and acquired some chunks of mahogany type wood from various friends.  As you will be familiar, or can become familiar, with John's plans I will mainly describe the changes I have made in my version of the construction which I have personalised as "Tonyphonic".

I constructed most of the organ using a circular saw bench, a planer/thicknesser, bench drilling machine and rotary sander, but had to use the lathe, flypress, milling machine and dividing head for some of the changed items.  I had to carefully plan the cutting of the birch ply as the whole sheet was required in the construction of the case, bellows/reservoir, pressure box etc. there being only a few scraps left over. The edging and base was made of pine. I made a special 1/2" fly cutter for the bellows/reservoir assembly so that I could obtain a nice sharp edge on the holes to give a good seal with the leather valves. All the wood was treated with 'sanding sealer' which brought up the grain and when re-sanded produced a nice smooth finish. The wind chests have a number of holes that need good edges for sealing the valves and these are in tempered hardboard which tends to throw up a burr if drilled. I found that punching these holes on the flypress gave a nice square edge so all holes in tempered hardboard were produced in this way. The sliders are made of plastic ABS sheet with the holes punched in the same way and the cover strips are made up of two pieces of tempered hardboard glued back to back so that there is a smooth surface on both sides. The holes in these were also punched. I have not used any M.D.F. The two reservoir springs were produced on a home made bending jig from 1/8"piano wire and give exactly 8 W.G.

The seven bearing crankshaft is fabricated in mild steel with aluminium housings for the ball races, aluminium connecting rods with threaded length adjusters and self aligning rod end bearings at the little end.  All shafts in the pressure box run on ball races, the take up spool being made of black plastic drainpipe, the flanges of which are cut out of black Bakelite sheet as is the music roll holder. The tracker bar is constructed from 1.5"diameter black anodised aluminium rod which was originally the platen taken from an old printer as were the 1/4"diameter pressure rods either side of the Perspex window. The pressure rods are mounted on ball races but there is not enough friction with the roll to rotate them. The anodising produces a clean smooth surface for the roll to run on. For indexing the tracker bar had to be drilled while mounted in the dividing head on the milling machine table. The holes were drilled from the top down to the centre of the bar then it was rotated by 120 degrees and another hole drilled to meet the first.  The next tracker hole was drilled in line with the first except this time the bar was rotated 120 degrees in the opposite direction bringing the hole out on the other side. Bringing the holes out on alternate sides allowed enough space to accommodate the aluminium nipples which connect the plastic pipes going to the bleed bar.

I decided against friction devices and belts for connecting the drive from the crankshaft to the take up spool and plumped for a gear drive instead. I made the gears from 'Delrin' because it is self lubricating, quiet and I had a bar of it in stock. I made them 16 DP because I had the cutters and all the gears run in their own ball races. This makes the whole assembly maintenance free which is a good job as I glued up the case in this area to avoid showing screw heads and now cannot get at it. The clutch that disconnects the drive during rewind is made from two Meccano contrate wheels which lock into each other like a multi tooth dog clutch. This is operated from the back of the organ by a square push rod with limit holes that locate with a ball and spring.

The bass pipes and bass helpers were made from pine, a quantity of which had been cut and planed into 1/8"and 3/16"sheets; the rest of the pipes were made from mahogany which had been prepared in the same way. Three of the bass pipes had to be mitred to get them into the base but by increasing the case height slightly I avoided having to mitre any of the accompaniment or melody pipes.  I did not encounter any difficulty in tuning the pipes with the tuning meter or setting the bleeds with the test roll.

I used 1/8" x 1 1/4" bright mild steel bar for the Glockenspiel, cutting each bar a little longer than John's dimension and grinding the ends until it was in tune with the meter. It makes a difference where the fixing holes are drilled in the bars. They should be drilled at the nodes these being 0.224L" in from the end of the bar (where L is the length of the bar in inches) thus allowing free resonance of the bar. The bars sit on felt discs and there is a piece of silicone rubber tube between the pin and bar hole as in John's organ. The hammer shafts were made from 3/32"bronze brazing rod with hardwood hammers at the ends. I had some 24swg piano wire that I used for the return springs and this works a treat. The bars were treated with a commercial blackening solution which gives them a uniform colour and should deter rusting.

To bring the organ up to cranking height and transport it I have made a wheel barrow-like trolley similar to that made by John Pettifer. This is a GT version with alloy wheels and removable handles. It has four tapered spikes on the top which locate with mating holes in the base of the organ and prevent it parting company during transport.

I know that I am getting old but having completed the organ I found that I could not pick it up to load it into the car. It only weighs 82lbs (37Kg for metric people) but is an awkward shape (being about 25"square x 37"high).  Only having handles at the side means increased leverage with arms outstretched. Also having no bottom to the case one has to be careful not to damage the bass pipes. I got over this by constructing a trestle the height of the car cargo area, lifting the organ on to this using a home made electric hoist and sliding it into the back of the car. It is easy to pick up if there are two people so getting it off the other end is no problem.

The whole job took nine months and after obtaining some rolls of Melvyn's excellent music I took it to the park and played it to the enjoyment of all but the stone deaf.  Despite much searching I have been unable to find a monkey who is prepared to turn out and collect money, so rather than get into cloning or genetic manipulation perhaps my next job should be to produce a mechanical one.
See Mechanical Monkey

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