Chassis for the Furness Railway J1 locomotive, designed as a Multi Build System ready for compensation or springing.
It must be stressed the set of Bearing Carriers included in this are not working 'Hornblocks' although they at first glance look similar. Some of them have a tiny square designed in, a little paint will show it up easier. This denotes it goes to the top of the chassis rather than the bottom.
The concept is simple, add the top bearing carrier into the hornguild style axle slides, carefully trimming if needed, then add in a loose 1/8th brass bush with the wheel set already built up and simply drop it in, then clamp the bush with the bottom bearing carrier. If you glue it solid then it will become a fixed axle, however if you carefully use some thin rod or scrap etch and use that as a carrier retainer and carefully glue this to the edges then you can clamp the carrier in place with provision to remove it later if needed. If you opt to keep the carrier 0.5 -1mm away from fully clamping the bush/wheelset in place then you effectively give it downward slop that can also be sprung. The P4 J1 chassis in the below video was built this way.
Alternate carriers will also be available that have ovals built in to various dimensions to account for different springing options. A set were trialed in Shapeways Steel to alleviate durability concerns but dimensionally these were not good enough and so were dropped, some extras are included and the spares that will be uploaded soon provide many in one pack. If anything does wear out then it is a simple task in replacing them, providing you don't glue them fast without a retaining piece.
Also of note, if you disregard the bearing carriers entirely then you will have a rectangular hole already cut out to the conventional dimensions for propriatory Hornblocks such as those from Alan Gibson, High Level Kits and London Road Models.
This system works and is quicker and easier to set the chassis up than a fixed axle even - that was the aim and it has been achieved but I am currently looking into a different manufacturing method such as milling becasue the chassis without retainers in position is very weak and is prone to bending or snapping. Only when the carriers are in place glued by a retainer is rigidity restored, and so it is for this reason that I will not be making every SCC loco chassis readily available with this system from the off. HOWEVER...
I am willing to make any of the SCC loco chassis with this system on sinsere request. Tell me which chassis you would like as a Multi Built System and I will get to work on it as it doesn't take too long to convert. No time wasters though please!
Dummy leaf springs are added as an optional add on although these need holes drilling in the shank and chassis and 0.45 rod or similar inserted.
Below is the instructions for the standard fixed axle versions as a lot is still relavent...
The axle holes need gentle reaming out to accept 2mm 'straw hat' and 1/8th 'top hat' bushes (bearings) Reaming them out slightly downwards to an oval and keeping the bushes loose makes a little bit of downward play to help with track holding and electrical conductivity. In trial builds the driving wheels were sprung downwards like this with the pickups killing two birds with one stone so to speak.
A spacing plate is sprued to the left hand side, this is to be cut off and glued in position relative to your motor and gearbox choice. It makes a good motor mounting plate too.
For the rear wheel you have the choice of a Pony type pivot arrangement or a double joined option more like the radial truck, use 10BA nuts and bolts, to fix these in place using the hole in the rear of the chassis (ream to a working clearance), add straw hats to these working pivot parts for best results, reaming them carefully to accept them tightly. The front chassis hole that is designed for body fixing is only to be reamed out only a little bit as the bolt will self tap, a retaining nut is not needed unless you want to add one. Brake pads are already in position but you will have to make your own brake rigging if required, on the insides are dimples to accept some thin brass rodding. 0.45 is a good choice.
Owing to various conflicting written information and drawings regarding the driving wheel diameters the descision was finally made and the chassis are designed to use Alan Gigson 5' 6" driving wheels, code G4866 for 00 and EM and code GS866 for P4. These wheels also have the correct crankpin throw. The front and rear wheels are 3' 6", Alan Gibson codes G4842 & GS842 respectively. No doubt other companies wheels can be used also, but they haven't been used in the initial builds to be able to advise accurately.
The slightly larger quoted (elsewhere) wheel sizes no doubt could be used with a bit of tweaking also but I'd go with the above as they are guaranteed to fit.
A London Road Models 1/50 Motor Mount (Gearbox) and a Mashima 1020 motor with added 6x12mm diametre flywheel with 1.5mm shaft hole was used in the photographs of the completed locomotive. (Please see the loco bodies section) Again, many options are available but these are known to fit easily. The only potential problem with this combination is a small hole in the cab below the firebox hole had to be cut out for the gear wheel, but after backhead, levers and crew were added to the finished locomotive you could only tell if you looked hard enough.
Here is a video of the J1 running. P4 in this case.
If you have any questions feel free to ask and I'll try to get back to you asap.