For those of you who worry that I’ve not been producinging anything, here is a list of recent etched coaches and npcs that have been updated and made available on the website.
BCK0260/4 NER D. 60 PBV
BCK0454/4 CLC D. 59 Cl
BCK0519/4 GCR D.1z5 milk van
BCK0532/4 GCR D. 5Q3 FK
BCK0534/4 GCR D. 5H1 BCK
BCK0580/4 CLC D. 15 T
BCK0790/4 M&GNR Large Stock Brake Van
BCK1036/4 LMS D.1879/1952/1956 HorseBox
BCK1766/4 MR D. 399 HorseBox
BCK1769/4 MR D. 529 Clayton 25′ PBV
BCK1788/4 MR D.429 Hound Van
BCK1798/4 MR D.403 CCT
BCK6820/4 B&CDR 5 Comp. Third Oldbury
BCK6821/4 B&CDR 6 Comp. Third Oldbury
BCK6822/4 B&CDR Brake Third Oldbury
Almost all the advances I had hoped for and wrote about in the last pasting have proved in one way or another a disappointment. Much of the reason for this lies with my growing understanding of the limitations of 3D printing and the present generation of materials used. So this summer has seen much wear on the path back to the drawing board.
Out of the fog of despondency some progress has bee made. I will be upgrading the main website in the next few weeks and add a number of coach etching that have existing production tools. To cut down confusion these will only be available with etched underframes. The long term intension is still to convert many of these to resin kits, and with so many available, and on my wish list, there is much development time to be spent refining my ideas and turning out patterns for models. As a basic principle I want to concentrate on those coaches that have a family affinity so that a single underframe moulding can be used for a number of different carriages.
The guinea-pig for this development work is the MET Dreadnought third. Some of you may have seen a body of this coach done as a one piece 3D print. However having spent a long time playing with it during the summer I reluctantly came to the conclusion that it was impossible to clean the stepping from the lower panels without compromising the beading. I have therefore decided to take a step back and make the patterns for the body by building up the thickness from brass etches. The design allows me to incorporate flanges at both the top and bottom of the sides. Etching drawings for the side and end components are finished and ready for printing.
I’ll be posting photos and graphic of this and other major components at various stages of their development to keep you informed of the progress.
After telling everyone I met at S4N that I was intending to produce coach kits consisting of etched sides and ends, and printed seat units, roofs underframes and bogies, I though it would be a good idea to get some costings. So using the LMS all third that has served as a guinea pig I drew a new seat/floor unit and uploaded to Shapeways to check the price. Unfortunately the total retail price came out at around £100. This I considered to be too much, so I have reluctantly had to shelve the whole idea. So all my future bogie coach kit are going to have resin bodies and roofs
I’ve had a prototype of one of the promised coach kits to work on over the last couple of weeks. It has taught me some interesting things about the sintered nylon I used. Basically while it will make acceptable underframes and roofs, getting the good finish needed for a coach side is all but impossible. So it’s one step back and one to the right and I’ll have to go off in a slightly different direction until the technology catchs up with me.
I had an enquiry this morning about some SECR coaches, and it may be worth posting much of my reply here to show everyone the way I’m thinking.
I’m working on a system to provide complete kits for most of the etched
coaches in the 4mm catalogue. This will consist of the body etch, more
or less as supplied at the moment, a roof, a floor/seat unit and one
piece underframes and bogies. Leaving the modeller only to supply
wheels, paint, glue etc. The price is likely to be in the region of
£70-80 depending on the prototype.
I’m also working on a alternative version of this system that uses cast
resin sides and ends instead of the brass ones. This has the potential
to be offered painted and ready to run, but is somewhat further away.
This latter item is the way I’m intending to produce the lits advertised in the coach kit section of the main website.
A recent thread on the Scalefour Society Forum has reminded me that there is a much easier solution to the ‘side-play on the middle wheel’ problem. On the original full sized coaches the springs for the centre axle were supported in long j-hangers with either with links or rods and rubber secondary springs. The axleboxes were modified so they and the axle could move axially in the w-irons. We can’t actually make the axleboxes move like this on models but we can get very close to it. This is how:-
A pair of wheels, almost any make will do.
A length of brass tube 2 mm OD x 1 mm ID x 22 mm long, for P4 or EM, or 20 mm long for OO
One ExactoScale pin-point axle 1mm diameter
Cut the tube to length and make sure that both the outer an inner edges are well de-burred.
Remove the wheels from their axle and mount them on the brass tube. Check and adjust the back-to-back.
Slip the mounted wheels onto the 1mm axle and mount the combined axle in the sprung w-iron in the usual way.
There you have it. Quick, simple and without the usual contraptions or inside bearings. THis method will give enough side-play for your six-wheeler to go round any curve which doesn’t produce buffer locking.