loco construction
- loco construction index
- 3D printing of a class 85
- building a V36
- type 81 scratch building
- Designing a type 16 steamer
- scratch building a type 31 consolidation
- ideas about a type 29 steamer
- tender constructions
- small conversions
- a more complex conversion
- Br65 conversion
- type 97 conversion
Preparations on building a type 29
Some pictures of ideas on building parts for a type 29 steam locomotive. Basic method is by exploiting the milling machine.
The last survivor still in running condition in 1995 in Leuven.
Frame
The frame parts cut from PB.
The type 29 has a bar frame. That can be milled from flat sheet. To obtain a robust frame a sheet of 0.8 mm Phospor Bronze was glued to a piece of sacrificial MDF and the outline of the frames were cut. In this case with a rather coarse milling cutter of 1 mm as the 0.8 mm were gone and any smaller looked a too great risk for this hard material.
Wheels
Another method for producing spoke wheels
A basic wheel drawn in 3D using ViaCad.
The test wheel cut from clear plastic on a piece of polystyrene as carrier.
The wheel pressed out of the carrier
A piece of 2 mm polystyreen is acting as carrier. On the lathe a 1.5 mm thick disc with a 2.5 mm stub was turned from a clear material. Although I thought it to be polycarbonate it is more likely PMMA as it seems a bit soft for PC. A 2.5 mm hole was drilled in the polystyrene and the stub glued in with cyano. Than the machine did its work and it certainly looks like a wheel that is coming out. A 0.3 mm straight cutter was used for the contour cutting. So far so good, looks promising, now assembling and a test on stability
A set of assembled wheels made from POM with silversteel rims.
A set of assembled wheels made from POM with silversteel tyre. Although not perfect they will do the job, assembly and rim production need attention for an optimal product. The above 10x enlargement shows apart from the filth that an extra step for rounding of the contour cannot do harm but this requires a round nose tool not available at the moment. These centers survived the treatment of finishing the tyre and drilling the center on the lathe, thus seem rigid enough. Of course there is a chance the rims come off, these are glued with cyano which seems allright for bonding to metal according Wikipedia. If necessary producing a groove at the inner contact area for an extra ridge of glue may prevent such. Optimising the process requires producing some tools for the lathe to assist production of tyres as these take much more time than the wheel centers due to tool changes, necessitating measuring actual dimensions.
Variation on the theme with integrated balance weight.
The result coloured with a filt scriber, looks a bit smudgy with this enlargement but with some cleaning using a glass fiber brush all loose material will disappear.
a pair of black wheels
A pair of wheel centers produced from black POM, much easier and cheaper than trying to colour the white POM with Dylon paint. The right hand is the main driver, this shows some flash due to using a different cutter and cutting strategy in trying to copy the blended surfaces of the original drawing above. This was not succesful as you can see, apart from the flash, the surfaces of the spokes are still flat. Another attempt will be done with smaller steps and a finer cutting program for only the top 0.25 mm. The top of the spokes are no longer flat although its not to 100% satisfaction. The surface of the balance weight is more smooth and is now glossy. I noted some stability problems with the carrier moving slightly due to forces, a more stable carrier material will take care of this.
A handful of wheels
Tyres were produced on the Proxxon from automate steel. Using a set of quick change toolholders really helps to speed this process up and gives uniform results with less measuring in between. The next practical step is production of the axles and drilling the holes for the axle and the rods. This requires to produce a collet to hold them in the lathe for drilling the holes.
NMBS 29.013 in 2010 in Dorinne-Durnal at the CFB
Desk study
Starting a desk study, track and wheels as existing drawing parts.
A start was made by setting up a drawing of the loco in Cinema 4D, this serves the purpose of getting all the necessary dimensions from the drawings and make subdrawings for the components and form ideas how these can be produced. The STL file of the wheel drawing was imported and visualised similar to the type 16 design study ,see type 16. This should lead to drawings for the upper parts that can either be made using the available tools in the workshop or alternatively used to order externally produced 3D printed components. Setting up this arrangement makes it immediately clear the that maximal dimension for the wheel flanges is 0.3 mm otherwise the wheels are not going to fit the chassis.
smokebox door.
The smoke box door, a job similar to that on other models only the circle with bolts is additional.
Boiler with firebox and smokebox including door.
Constructing such a boiler is best done from 2 parts soldered together, a boiler made from brass tube on the lathe and a separate firebox which can be constructed similar to the one for the type 25 from brass on the milling machine.
sandbox on top of the boiler and a first impression of the cylinders.
Construction of the cylinder block and steam pipe, basically a set of 2-D profiles, one for the cylinder block and one for the saddle with the vertical center plate where they are bolted together. The cylinder and steam distribution and steam pipe are inserted as cylinders. The whole lot is a symmetry element of course. Construction in metal is possible by milling 2 of these profiles as one unit in pcb material and space these apart using the cylinders as distance keepers and wrap a thin sheet of metal along the outline. The pcb material allows to use the cylinder block as insulated frame spacer solder. Alternatively the block can be entirely milled as single piece from plastic using 2 sided milling from front and back or as 2 single sided milled pieces glued back to back.
cab added
front of the footplate.
deflection plates and chimney added.
more appendages added to the top of the boiler.
Comparing the generated pictures with that on the 2010 photo shows several deviations particularly at the firebox end. A view into the cause revealed that some of my working copies of the drawings have different x and y scale problably due to some scanner or printing operation. This caused the deflectors to be too high and also the end of firebox did not sit correct. On the above picture these items are repaired. Also there exist several differences between the 29.013 and my drawings. Some of these do originate from the new boiler built in Meiningen, particularly the number and position of the washing plugs, the position of the electric generator and the 180 degrees switched steam connection in front of the sandbox. The cab is now modified to reflect the correct height and has its partial back wall and there is a rainstrip on the roof.
sand pipes on the boiler.
some colour added
A set of fireboxes and cylinder blocks as 3D printed items
By now these are old results with a 3D printed boiler from the Anycubic Photon printer compared to boiler from brass. Apart from the slicing error in the chimney the result is perfect. The black parts were done in ABS on an even older printer. The above drawings fed to a machine with higher resolutin than the anycubic will offer a far better result and can also include most of the pipework reducing amaount of loose components. But first some frame construction is necessary by producing gears and finishing the wheels for a running frame.
--> sometimes years ...5, 6, 7, 8,... pass ... and then suddenly things move forward again -->
Design of drive mechanism with motor in boiler
Sideview of new conventional frame with dropout axles, note the inserts to adjust the vertical axle space.
Top view and wheels
The initial choice was for a cardan drive, that is why the wormwheel sits in the frame. This is a homemade 36t M0.2 skew worm leading to 1:44 geardrive. When in practice this gearing turns out to be too high then this worm can be easily changed for a 24t M0.3 leading to 1:29 geardrive or 1:22 with M0.4. But on second thoughts, on playing with the mechanism, this lead to a further study to see if the motor could be accommodated in the boiler. The above updated sketch shows that that is feasible. The gearbox can be hidden in the firebox and the boiler can be fitted around the motor. The gearbox also allows to support the cab. The tender can than serve as carrier for a sound decoder and pickup. This would also allow the gears to sit in the center of the frame and that makes it easier to fit brakes and pick-ups on the keeper plate. All this to take in account on a redesign for #2 (if ever).
View with motor mounted, it is a bit a of a fiddle to get the worm seated at the right height over the worm, better solutions to aid ease of assembly here are possible, but the purpose was to study feasibility with a quick solution for already existing parts.
This image demonstrates the idea with the metal boiler and temporary cylinder block mounted.
Above images show that this solution is feasible. Driven heels are running but the 2 intermediate gears between gearbox and wheels need attention as sometimes there is a glitch, some polishing of sides and sidewall will probably help this. Also some wheels need further attention as two of them show too much wobble as is, either refit the tyre or use a spare one. After cutting and fitting the rods it will be time for doing test runs on track.
p.s. This is a low profile project with slow progress.
copyright: Henk Oversloot
start: 10 june 2013
latest update: 14 Nov 2024