JimG
Western Thunderer
I've decided to start doing something about freight rolling stock for the garden. I've been doing a bit of work in S scale to produce wagon kits for the S Scale Society and I decided to upscale the work to 1:32 scale. The wagon body will be made from laser cut MDF and the underframe from machined wood parts.
The wagon to be made is a Caledonian Diagram 24 wagon which was a pretty straightforward general goods wagon with a side door. A start was made to produce the wooden parts for the underframe. I used a sheet of 4mm wood and thicknessed it on the milling machine to give the prototype thickness of 4.5" which is 3.6mm in 1:32 scale.
It all gets a bit messy and the workshop vacuum cleaner comes into its own. The sheet was actually close to 4.75mm thick (old 3/16") so there was a fair bit to remove.
The thicknessing is complete. The lower section closer to camera is to 2.6mm for the solebars since I intend to place a 1mm layer on the outside of the solebars to cover the heads of screws holding the "W" irons.
The main holes are starting to be cut with 4mm holes for the buffer stocks and 1.5mm slots for the coupling hooks.
Later on in the process, all the holes have been drilled, including the ones in the solebars to hold the "W" irons, the slots have been cut for the joints, and the cutter is now part way through the parting cuts between all the parts. There will be parts for two underframes.
The parts after cutting with a partial assembly of the solebars and the intermediate crossbeams in the foreground.
And as if by magic, a laser cut and glued body appears. You can't show much during laser cutting.
The underframe has been put together.
Sprung "W" irons have been etched and assembled with a bit of 13 thou guitar string as a spring. This has been the result of a few years of development and now works very well. I will make another photo tool to fine tune a couple of dimensions bit the present ones work very well as they are. I've made the "W" irons as individual units. It's an expensive way to get 28 thou nickel silver if I drew up the traditional "W" iron assembly. If I want to have the assemble then I will cut some strip of the appropriate size and solder a "W" iron on each end.
The underframe with the four "W" irons fitted using 10BA countersunk screws and nuts and washers.
The underframe is placed under the body and with a set of Slaters wheels fitted. I made use of my ER25 collet set to ballast the wagon to deflect the springs to the correct height. The collets weigh in at 330gms and the wagon parts at around 50gms. I only chose the 13 thou spring wire since it looked about right after my previous experience with springs. I haven't used Russ Elliot's formula as yet but I've no doubt it will come out with the same results from previous experience. I will be able to ballast the wagon by putting some lead sheet in the pocket in the centre of the underframe. If I can't get the weight of the lead up to 330 gms then I can reduce the size of the wire to 12 thou or 11 thou.
A close shot of one of the "W" irons shows the bearing in the correct position with the collet ballast with about 1mm gap at the top of the bearing slot. The "W" iron is designed to give +/- 1mm movement.
This wagon, and another set of body and underframe bits, will be the guinea pigs for a few other methods - like using the CNC mill on the laser cut sides to machine bevelling on the curb rail corners. I'm also workign on how I will represent the nuts on the platework.
I'm also debating on what to do about other hardware, like the springs, axleboxes and buffer stocks. If I can produce them fairly quickly on the CNC mill and the lathe then I might not consider getting them cast. But I'll wait until I've made a set when the temptation to get them cast might be too much.
Jim.
The wagon to be made is a Caledonian Diagram 24 wagon which was a pretty straightforward general goods wagon with a side door. A start was made to produce the wooden parts for the underframe. I used a sheet of 4mm wood and thicknessed it on the milling machine to give the prototype thickness of 4.5" which is 3.6mm in 1:32 scale.
It all gets a bit messy and the workshop vacuum cleaner comes into its own. The sheet was actually close to 4.75mm thick (old 3/16") so there was a fair bit to remove.
The thicknessing is complete. The lower section closer to camera is to 2.6mm for the solebars since I intend to place a 1mm layer on the outside of the solebars to cover the heads of screws holding the "W" irons.
The main holes are starting to be cut with 4mm holes for the buffer stocks and 1.5mm slots for the coupling hooks.
Later on in the process, all the holes have been drilled, including the ones in the solebars to hold the "W" irons, the slots have been cut for the joints, and the cutter is now part way through the parting cuts between all the parts. There will be parts for two underframes.
The parts after cutting with a partial assembly of the solebars and the intermediate crossbeams in the foreground.
And as if by magic, a laser cut and glued body appears. You can't show much during laser cutting.
The underframe has been put together.
Sprung "W" irons have been etched and assembled with a bit of 13 thou guitar string as a spring. This has been the result of a few years of development and now works very well. I will make another photo tool to fine tune a couple of dimensions bit the present ones work very well as they are. I've made the "W" irons as individual units. It's an expensive way to get 28 thou nickel silver if I drew up the traditional "W" iron assembly. If I want to have the assemble then I will cut some strip of the appropriate size and solder a "W" iron on each end.
The underframe with the four "W" irons fitted using 10BA countersunk screws and nuts and washers.
The underframe is placed under the body and with a set of Slaters wheels fitted. I made use of my ER25 collet set to ballast the wagon to deflect the springs to the correct height. The collets weigh in at 330gms and the wagon parts at around 50gms. I only chose the 13 thou spring wire since it looked about right after my previous experience with springs. I haven't used Russ Elliot's formula as yet but I've no doubt it will come out with the same results from previous experience. I will be able to ballast the wagon by putting some lead sheet in the pocket in the centre of the underframe. If I can't get the weight of the lead up to 330 gms then I can reduce the size of the wire to 12 thou or 11 thou.
A close shot of one of the "W" irons shows the bearing in the correct position with the collet ballast with about 1mm gap at the top of the bearing slot. The "W" iron is designed to give +/- 1mm movement.
This wagon, and another set of body and underframe bits, will be the guinea pigs for a few other methods - like using the CNC mill on the laser cut sides to machine bevelling on the curb rail corners. I'm also workign on how I will represent the nuts on the platework.
I'm also debating on what to do about other hardware, like the springs, axleboxes and buffer stocks. If I can produce them fairly quickly on the CNC mill and the lathe then I might not consider getting them cast. But I'll wait until I've made a set when the temptation to get them cast might be too much.
Jim.