"Lincoln Mill Engine" Duplex, Casting Set & Drawing
The design of these engines is of the type that were made for 100 years or more 'till the end of steam. Robey, Marshall, Foster and hundreds of other firms, a lot of them unheard of now, all made amongst other things, steam engines - thousands of them.
From the single cylinder engines to the large twin tandem compounds up to 3,000 h.p. that drove the cotton mills of Lancashire they all came under the heading of "Mill Engines". One thing they all had in common was that they did not reverse. Only specialised engines such as rolling mills, colliery winding and the like were built to reverse.
Although different maker's engines within a range looked similar to the casual observer, each manufacturer had their own style of doing things, Robeys of Lincoln made as many as most and it is this firm's engines that we have based our design on. Using cylinder diameters of ¾ in. and 1 3/16 in. with a stroke of I ½ in. We have produced five different engine arrangements using common components. All are slide valves.
Apart from the engines illustrated there is the duplex arrangement using two ¾ in. bore cylinders side by side, also the twin tandem compound which consists of two tandem compounds side by side driving a 7in. flywheel with 9 grooves. However it is thought that Robeys never made the four cylinder arrangement using slide valves, but other firms did.
Sets of castings are supplied with the main bearing / trunk guide in two pieces for ease of machining the trunk. All casting are produced using metal patterns and are in gun-metal except the flywheel and crank disc which are iron. The flywheels are 7in. diameter, except for the single cylinder engine which is 6in. 0-Rings for pistons and glands along with Allen screws for securing cylinder feet and trunk guide to main frames are supplied. Nuts, bolts steel etc. are not supplied, but are easily obtainable from most model engineering suppliers.
Except for the twin tandem compound we can supply aluminium bases with the flywheel slot cast in, otherwise a wooden base needs constructing. To simulate the engine room floor the base top needs to be covered with wood or laminate tiles, chequer plate can also be used which we supply.
Drawings are full size with machining notes and constructional drawings for the trickier components included. Sheet 1 shows a general arrangement of the tandem compound from which all the other engine arrangements can easily be deduced.
A lathe of not less than 3 ½ in centre height such as the Myford ML7 is required to machine the castings, unless of course a friend can turn the flywheel for you.
We often get asked if we can supply separate castings, if one is scrapped. "Yes of course we can".
Single Cylinder 11 ½ in. x 5 ½ in. Tandem compound I5 ½ in. x 5 ½ in.
Cross compound l2in. x 7 ½ in. Twin tandem compound 15 ½ in. x 9 ½ in.
The construction of the Tandem Compound was described in 'The Model Engineer' between 16th. October 1992 and 16th. July 1993.