© 2006 SEAMS

 

In over ten years of involvement in the restoration of stationary engines and related equipment, SEAMS members have amassed a significant amount of experience. We were therefore well pleased when asked to take on a project to return the large Tangye producer gas engine to working order. The owner has dedicated himself to restoring the mill which had fallen in to decay having been standing idle and largely untouched since the 1960's. This task is now largely complete but the restoration of the engine and gas plant, still in its original location, was a task that he felt was best attempted by a group like SEAMS.

 

The Mill

First recorded mention of a mill on the site was in the Hickstead Estate records for 1605 referring to the division of land ‘abutting a brook running from Cobb's Mill to Herrings Bridge on the north east of the lands of Thomas Avery'. Land tax records indicate that John Lindfield owned Cobb's Mill in 1780. The leasehold passed to Nathaniel Avery (by 1785) and then Thomas Avery (1786) before reverting to William Lindfield by 1808. A Henry Pickett is named as the leaseholder in 1809. By the end of the Napoleonic wars, Cobbs Mill was owned by Anthony Ede of Shermanbury but passed to his son Thomas Ede by the time the leasehold was again offered for sale in 1834 and taken up by Henry Pickett. The property was then let to Charles Packham when the previous tenant James Mitchell had departed for Duncton postmill at Clayton. In 1865, the property was being offered for sale by the trustees of the Late Mr Edward Pickett, Henry Pickett's son. The sale notice records the mill to have been a brick and timber built structure driving four pairs of stones and stood upon a stream with a fine supply of water. The tenant was Charles Packham, likely the son of the 'Charles Packham' who had been active in 1834. An article in Sussex Country Life published in 1947 claims the brothers Charles and Benjamin Packham were working in 1850 and that Benjamin and his nephew Charles Packham worked from 1875 until 1881 when Benjamin left for Leigh Mill in Cuckfield. Charles Packham then ran Cobbs Mill alone from 1881 until his death in 1912 being succeeded first by his widow and then Charles Packham Ltd.

The mill machinery survives largely intact and is mostly Victorian. This must have been a substitution for the original machinery. The Mill is now a mixture of dates and styles ranging from a small part of the east wall of the tile hung cottage believed to have late mediaeval original to the 17th century tile hung wood framing of the millers cottage , the 19th century elevations of the mill itself and the imposing brickwork of the mansion added to the north in 1877.

 

The Engine

The engine is a Tangye producer gas engine number 12330 believed to have been installed circa 1910. The engine and producer gas plant, number 5549 and built by the National Gas Engine Co at Ashton Under Lyne, are thought to have been second hand when supplied by W Holloway and Sons, Engineers of Shoreham Sussex. It is quite possible that previous duties involved electricity generation because of the two heavy duty flywheels for steady running. There were also many 'used' spare parts surviving, possibly from sister engine/s. Anecdotal evidence of a mishap still lives in memory. It is reported that one day, whilst the normal engineer was absent, an attempt was made to start the engine using the mill overshot water wheel to drive it over. This resulted in the engine firing at the wrong point in the cycle and irreparable damage to one of the flywheels. To this day one flywheel is clearly a replacement being smaller (66") than the other (72") and carrying the serial number of a much earlier Tangye engine number 5112 and marked "Tangye and Bailey Patents Process". The engine bore is 13" and believed to be the K size from the X type range of Tangye range produced up to and including 22" bores.

Preservation

It was back in late 2004 that a group of SEAMS members started work cleaning and repairing with a view to getting the engine running. The National Producer gas plant (installed second hand with the engine but not considered safe to ever run again) was cleaned and painted. A major job was removing the 14" diameter piston and connecting rod to free off rings stuck after many years of hibernation. Main bearing caps were removed to check, scrape the bearings and clean the oil ways. Many parts were stripped out, cleaned and any significant wear rectified before replacement and the three main valves were removed and ground in. Other tasks included rigging a water cooling system as the original pumped system was deemed unsuitable and could not be protected by antifreeze. The alignment of the crank was checked since subsidence of the outrigger bearing outboard of the main drive pulley was likely. Only a small adjustment was required to this bearing.

 

Starting

It was towards the end of spring 2005 that enough progress had been made to attempt a start. The Tangye patent petro-gas starting system had been renovated and new rings installed on the charging cylinder. After much discussion about the starting procedure some old books were produced and a procedure adopted. The piston was set in the correct position on the power stroke and with the con-rod at about 45 degrees to horizontal. The starter enables the cylinder to be charged with an air petrol vapour mixture which after isolating the starter, could be fired by tripping the ignitor/magneto to produce a spark. After many years of being idle, compression was not good and only a few revolutions of the engine could be gained by this method. A Guldner diesel donkey engine was rigged to turn the engine over and run in the rings. This worked to some extent but the engine is of such a size that there was barely enough power and the drive belt couldn't take the load. At that point, summer and the rally season had arrived so we retired to ponder our next move.

 

Towards the end of 2005 and the cessation of summer rally activities, work resumed on the engine and a Petter diesel donkey engine was permanently installed on site to drive the engine. A reduction drive from the Petter to the main Tangye drive pulley enabled a suitable rotational speed to be achieved and maintained.

 

Now we had a method to turn the engine over for starting, the fun started with attempts to provide the correct gas/air mixture to the engine. Producer gas is of very poor quality yet we had to run the engine on bottled gas, propane in this case. This is of much higher calorific value so less gas is required. It is also supplied from the bottle at pressure so again very little was required. Getting the right mixture on a regular basis for such a large engine was proving difficult. Two 'on demand' gas supply diaphragm type valves were made to allow gas to be drawn only when required and both types had some success but continuous running still proved elusive. Finally in February 2006, a gas valve operated from the main inlet valve was fitted to feed gas at the correct point in the cycle. After connecting a battery to the engine ignitor to provide a good spark (original magneto was under suspicion) the engine fired and continued to run. It settled down to run at a constant and regular speed under the control of the governor. When the battery was removed, the engine continued to run. That was a great moment which all those involved will savour for years to come though the ducks scared away by the sound of the exhaust may have another view...

 

The engine and mill will be open for viewing every National Mills weekend when SEAMS plan to have the Tangye running as well as other mill related equipment and engines on display.

 

The photographs of the mill show various parts of the mill working and the engine.

The Mill and Machinery

The restored overshot water wheel with replacement buckets and with the engine house behind.

 

The main drive shaft taken from the water wheel and to the millstones via bevel gears which can be engaged or disengaged as required.

 

The 'stone' boxes covering the millstones on the floor above the main drive shaft

 

The Tangye Engine

 

'The starting pump side of the engine' with the 'National' gas producer immediately to the left of picture. The inlet silencer, filled with coconut matting can be seen at ground level with the hand start pump just above.

 

'Belting up the donkey engine' The trip magneto, supplying a low voltage to the 'ignitors' or points located inside the combustion space, can be seen adjacent to the engine speed governor. The engine drive pulley engaged via a clutch can be seen on the extreme right and this is where the donkey engine now drives the engine over for starting

 

'Bearing damage' One of the main engine bearings had been scored by the entry of dirt. Though not so serious for an engine that no longer has to work hard for a living, this has now been scraped to removed most of the damage.

 

'Suppliers Plate W Holloway and Sons Shoreham'  W Holloway and sons were engineers and Millwrights and supplied machinery to many mills throughout the south. It is thought this engine and the used spares that came with it, was supplied second hand.

 

'A smoky start' one of the first 'runs' and an encouraging start.

 

The picture is of Robert Edwards, Publican who had worked for W Holloway and Sons, Shoreham.

 

 

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