The MUNCASTER steam-engine models EDGAR T. WESTBURY glances back with a modern eye toosome classic models of the past N THE COURSE of the long history caster is well remembered as a special- fore, need despise the crude and Of MODEL ENGINEER-now, in- ist in the design of all types of steam primitive types of models produced I cidentally, approaching 60 engines, whose excellent drawings of by beginners, so long as they lead on to years-many notable designs and many types of stationary and marine the more realistic types which were engines in early volumes of the M.E., Muncaster’s speciality. descriptive articles have been pub- and also in the handbook Model The simplest form of engine de- lished which have established tradi- Stationary Engines, published nearly scribed by Muncaster is one having a tions or marked milestones of half a century ago, provided scope single-acting oscillating cylinder (Fig. progress in model engineering. for the talents of innumerable con- 1) and this will commend itself to Not only are these remembered by structors. many readers, not only on account old readers but they are often the H. Muncaster was a practical of its simple construction, but also subject of considerable discussion. draughtsman who not only had a because it can be built without castings. and requests for further information wide experience of steam-engine design It is of the type which would now be about them are constantly encountered. but also obviously had a love and classed as “ inverted ” vertical, having A few of the authors of these features devotion to his craft, and to all the cylinder below the crankshaft, are still with us, and in one or two things mechanical. In the introduc- though in the early days the practice cases continue to contribute articles; tion to his book he pays due homage of locating the cylinder at a low level- but most of them have passed on and firmly bolted to the floor if possible- are no longer available to provide was considered normal and orthodox. either new designs or guidance on their earlier ones. THE PILLAR Many readers have suggested that 1-A simple The main structural component of the M.E. should reprint some of these this engine is the pillar, shown in earlier features, but while this might Fig. 2, the lower portion of which is be a good idea, from certain aspects oscillating of rectangular section, with extended there are several reasons why the feet at the sides for mounting on the policy has not been adopted by this flat square baseplate.At the top end, journal. In the first place, although the section is also rectangular and is the designs for models do not neces- engine cross bored to form a housing for the sarily become outdated the mode of single main crankshaft bearing. .In treatment, including methods of con- the centre, it is turned to circular struction, is subject to certain changes tapered form, with simple ornamenta- as workshop equipment and technique to the many early engineers and tion in the form of a beading near the improve. inventors who contributed to the lower end. development of the steam-engine, To save material in making this In modern setting and also gives a complete answer to part, the foot at the base may be To many modern readers, reprinting those who would condemn model made separate and silver-soldered on; of old articles or designs may seem engineers for“living in the past.” or screwing and sweating would to be a policy of retrogression, or at “For the purposes of the model probably be satisfactory. This should least stagnation;it may even give engineer,” he states, “it does not be done before machining and I the impression that there is a dearth follow that the most recent and perfect suggest that the front and rear sides of new ideas in model engineering- engines are most suitable; on the should then be faced quite flat and which is far from being the case. other hand, some of the older engines true by filing, or any other convenient Therefore the idea of verbatim re- form subjects better adapted and more method, after which the two ends prints of articles is not considered fitted as prototypes for models, being may be marked out, exactly central desirable, but there is much to be said more picturesque and providing better both ways, and centre-drilled so that for the revival of old designs in a object lessons.” the part can be mounted between modem setting. With which precepts I whole- centres for turning. There can be few model engineers heartedly agree, and also with his The cross holes for the main bearing who have not heard of such pioneers further comments that many of the and the cylinder trunnion may now as Henry Greenly, C. S. Lake, Fred most popular so-called models “ have be drilled, and it is essential that Westmoreland, H. H. Groves, George no prototype in reality, but neverthe- these should be exactly square with Gentry, or the traction engine special- less may be useful in illustrating some the pillar face, so it will be advisable, ist “ Frost-spike,” who have been of the points of the steam-engine, as after marking out their positions, to acknowledged masters in a very wide well as providing a simple motor, set the pillar up on the faceplate of and versatile field of design. Last where only a small amount of power is the lathe for these operations. but not least, the name of H. Mun- required.”No model engineer, there- An alternative to the pillar as the MODEL ENGINEER 270 21 FEBRUARY 1957 support for the crankshaft bearing is These conditions can be assured by working to the same index reading on given in Fig. 3. This consists of an machining, as the bore and flange the topslide for each cut, the shape A-frame cut from sheet metal, with can be dealt with at one setting; may be made practically circular the bearing housing at the apex, a D-bit is recommended for taking the and flush with the upper turned part, either bushed or otherwise reinforced final cut in a blind bore, after which needing only a clean-up with a smooth to provide extra bearing surface. It it should be finished by lapping with file to take off the sub-angular corners, does not, however, incorporate the aluminium oxide or brick dust on and a final polish with emery cloth. port block or other cylinder mounting a short copper or aluminium lap- The trunnion is fitted to a tapped and it is not explained how this should not one which extends the full length hole in the face of the portblock, be fitted. For this particular type of of the bore, as this will tend to make and it is most essential that this engine, I do not consider it so elegant it tapered or bell-mouthed. should be dead square with the cylin- in appearance as the pillar, neither If the cylinder is machined from the der axis.It could well be drilled and does it simplify construction. solid the smallest diameter of bar tapped while the cylinder is set up which can be used is 1 in. A good on the faceplate’, to ensure this; the CYLINDER deal of material will. be left around hole should not go right through into The designer suggests that the the base, after turning as much as the bore, though some constructors cylinder (Fig. 4) may be made from a possible of the outside, and this will may find difficulty in tapping a short piece of brass tube, with the flange, have to be filed or machined away, blind hole. end cap and portface soldered on, leaving the portface to be faced flat. If it does go through, however, The components of the engine but in practice it will usually be found A very efficient way of doing this is make certain that the trunnion stud just as easy to machine it from the to make a short mandrel, of a size to does not project into the bore when solid, as the manipulation of small fit neatly in the cylinder, and fix this tightly screwed in and that there are pieces, which have to be accurately in an angle-plate or a short piece of no burrs left on the inside to interfere located and soldered simultaneously, angle iron, on the lathe faceplate. with the free movement of the piston. is not as simple as it looks.In either Clamp the cylinder endwise on this, It is an advantage to machine a shallow case, however, it is essential that the checking it first to see that it is parallel recess around the tapped hole to bore of the cylinder should be exactly with the faceplate; it can then be relieve the centre of the face; alter- circular and parallel, the flange faced turned into any position to‘ machine natively, this may be done on the square with it, and the portface dead the portface of “nibble” away the corresponding face of the pillar. flat and parallel to the axis. rest of the surplus material. By Little need be said about the cylinder 21 FEBRUAltY 1957 271 MODEL ENGINEER Muncaster that they are correctly located in relation to each other, First of all, the hole m the cylinder steam-engine is marked out as correctly as possible and drilled undersize, say 5/64 in. or No 48 drill, the hole being con- models .