John has every reason to be pleased with Scott Yeo’s efforts.
John Hobbs discovers more about John Williams’ Robey tandem roller No 42129 of 1924, which has just been restored… and its Danish-built counterpart.
There are several of these rather unusual rollers that have survived into preservation, the most recent restoration being that of No 42129, owned by John Williams of Camborne, Cornwall.
This engine has never been owned outside the duchy for it was purchased new by R Dingle & Sons on 5 December 1924, when its registration mark was changed from FE 6582 to the Cornish one of RL 75. Subsequent owners were GA Dingle (no relation) of Kelly Bray, Joe Deacon of Wadebridge (by 1960, and who also owned another tandem roller, No 48869 (EDV 916), David Hart of Camborne (by 1978), Paul Richards also of Camborne (in the following year) and, finally, John Williams, who bought the roller in 1987 as a kit of parts.
The crankshaft looks good.
When it was acquired by Joe Deacon, the purchase price was reported to be £600 or, so I’m told, ‘£100 per bullet hole in the spectacle plate!’ It seems that the roller was hit at least six times during a wartime raid on RAF St Mawgan, but unfortunately the damaged plate has ‘gone missing’. I first became aware of this roller after boilersmith Roger Pridham had made a new barrel for the overall ‘pistol shape’ boiler, arguably the type’s most interesting feature, in 1992. Robey more properly described the boiler as ‘being of the locomotive type with round firebox and no stays, this latter feature eliminating one of the chief boiler troubles. It is constructed of the best mild steel plates, and has a very large heating surface and grate area.’
The working pressure of the boiler was recorded as 200psi, the safety valves being of the Ramsbottom type. Not long after the boiler was returned to John, personal and health reasons forced him to postpone the restoration of his roller for several years until he felt able to take up the challenge of returning the Robey to the road. As the roller was very much in pieces and without drawings, the challenge was both physical and theoretical, with John deciding to place the restoration in the very capable hands of Scott Yeo, of nearby Ponsanooth. In the first instance, Scott collected the boiler, which was coated with rust. Although it had been protected from the elements, the weather in John’s part of Cornwall can be quite intrusive, particularly when the wind and rain drive in from the Western Approaches.
SA fine example of restoration.
Having returned the boiler to a condition that was very much better than the presentable condition in which he collected it, Scott set about the reassembly of the compound cylinder, honing and relining both bores and securing it to the saddle that was already in place. He then tackled the motion by grinding the crankshaft and renewing or reworking bearings and bushes where the need arose. A feature of the drive of this single-speed roller is the trunnion bar or main ‘axle’ that passes through a strong steam-tight tube from one side of the top of the firebox to the other.
Care has to be taken to ensure that clearances are not too tight because of the impact that variations in the coefficients of expansion of the metals used might have, keeping very much in mind the fact that the drive of this type of tandem roller is by chain to the rear roll. The original bar did turn out to be ‘deformed’ and was replaced by a new one. To obtain its maximum efficiency when in commercial use, the speedy roller had to be capable of quick movements from forward to reverse to forward again, so freedom of movement, particularly when rolling, is of paramount importance.
