Hints and Tips
So, What's in the Box? 
The kits contain all the parts needed to build all the variations that might be seen on a particular locomotive in as much detail as possible.  Simply, you choose what individual locomotive you want to build and the kit supplies the parts you need.  However, if we included, for example, all four types of lamp bracket that a loco might need to track it through it's life time, cost would obviously increase. To keep costs down, when ordering or purchasing the kit you will be able to select exactly which type of lamp iron you want from our components range and then only have to pay for that one type of lamp iron. 
Wheels, Motors and gearboxes are your choice to purchase from your chosen supplier. We now stock Canon 1833 motors and are the only supplier of the superb range of SDMP geraboxes.

Etched parts in brass or nickel silver
The parts in Finney7 kits have been designed to fit together accurately.  There is therefore no need to file off large amounts of metal to get parts to fit or to fill unsightly gaps with solder.  Top quality lost-wax and white metal castings are 'standard' with Finney7 kits.  With very little, if any flash to remove, the castings are often almost good enough to use 'straight from the box'.
All too often kit instructions are unsatisfactory.  They might be poorly written and difficult to understand.  The drawing provided might simply be cobbled together prototype drawings which are really not what is required when assembling a kit.  The instructions in a Finney7 kit can be broken down into four elements.

Written text.  Relevant historical notes together with a step-by-step order of assembly which should be followed 'to the letter'. 
Parts list.  A full numbered list of etched and cast parts. 
Etched fret layouts.  Numbered layouts of the etched sheets which are used together with the written text to locate the various components. 
Assembly drawings.  The assembly drawings have been extracted from Martin's own drawings prepared as part of the design process.  They therefore faithfully show the individual parts which are clearly numbered.  When used together with the text, assembly becomes a straightforward exercise. Drawings are supplied full size for 7mm scale kits; placing a part on the drawing enables the modeller to confirm that the correct item has been selected from the etched fret.   This cannot be achieved by the use of perspective drawings.

Boiler rolling is not a difficult process and it is not necessary to use a rolling mill. (The modeller who intends to build a number of locomotives would doubtless find such a tool very useful.) Model Railway Journal Nos. 66/67 show how a boiler can be rolled using a round metal bar on a rubber pad with a successful result. The boilers in our kits are designed so that the metal only has to be rolled to a radius close to that finally required.  The design of the kit ensures that a round boiler of the required size will result.  The other point to bear in mind is that in some of our kits, surface detail may differ according to the period being modelled.  As an example, at one period a particular class of locomotives may have had flush rivets whereas later, snap-head rivets may have appeared.  So, do we supply a pre-rolled boiler embossed or a plain one? If we were to supply pre-rolled boilers they would be unembossed.  If you wanted to portray embossed snap-head rivets the first thing you would have to do would be to roll the boiler flat again in order to be able to add the rivet detail.  The boiler would then need rolling again.  This is obviously not a sensible option. 
Also consider a kit such as the GWR Bulldog.  To show later versions with the 3/4 coned boiler the smokebox/parallel portion in the kit needs to be modified.  This is much easier to do in the flat. 
Hence the reason why we do not supply pre-rolled boilers.
The Use of Resin 
The material used in the LNER A4, LMS Princess Coronation and Bulleid Light Pacific kits is an 'ENGINEERING POLYMER' specifically selected for its properties. In our opinion a prototypically accurate A4 or Princess Coronation cannot be formed solely from etched or cast metal parts. The A4 is a very complex shape with continually changing curves. In producing the pattern Martin has done the difficult part in producing a pattern by overlaying panels onto a framework. Every customer on buying an A4 kit gets an accurate detailed body produced to the highest standard which enables them to build a quality model. Otherwise the building of an A4 would probably be beyond the ability many modellers. Resin moulding has also enabled Martin to include many details as part of the casting eg A4 boiler bands (which are of scale thickness) boiler washout plugs, rivet detail, inspection panels etc. 
The Princess Coronation's shape is similarly complex where the firebox joins the boiler. Resin casting will ensure a top quality result for all builders. The Princess Coronation will consist of two mouldings and we also include the dome, top feed together with piping, boiler bands and the steam pipes and saddle. In the case of the steam pipes and smokebox saddle, the alternative would be to use a white-metal casting. With the dimensional limitations of the white-metal process a good deal of fitting would be required on the part of the builder to accurately mate the saddle and steam pipes with the smokebox. By using a resin casting, this difficulty is overcome and all customers can be assured of a perfect result. 
The RESIN used in the kits is highly stable and does not degrade over time.  Unlike metal casting processes, resin casting is a cold process with no distortion and minimal shrinkage during manufacture (less than 0.4%!).