Thursday, 13 November 2014

Bettendorf Bogies and Bolsters

American Models Bettendorf Bogie
Marbelup Models 3D-Printed Narrow Gauge Bolster

As supplied, the American Models Bettendorf bogies are designed for S scale standard gauge, i.e. 22.5 mm gauge.  The Marbelup Models 3D-printed narrow gauge bolsters greatly simplifies the process of converting the American Models bogie to narrow gauge.

* Limited quantity of American Models bogies available.

Assembly Tips


To install the 3D-printed narrow gauge bolsters, carefully remove the springs and separate the two side frames from the standard gauge bolster.

Tip: Work over a tray or shallow box to minimise the risk of losing springs.  The Kadee #241 manual uncoupling tool includes a “spring pic” which can be useful for removing and refitting springs.

Carefully remove the support structure from the 3D-printed bolsters using a sharp craft knife.  A knife with an Xacto No.11 blade is recommended.

If required, paint the narrow gauge bolsters and (optionally) the sideframes prior to reassembly.

Reassemble one sideframe of each bogie to a 3D-printed narrow gauge bolster.  Fit the second sideframe to each bogie but do not refit the springs at this stage.

Fit desired wheelsets by carefully twisting one sideframe with respect to the bolster.  Wheelsets must have 26 mm axles.

Refit springs to second sideframe of each bogie.

The pivot hole in the 3D-printed bolsters is designed for 2-56 (or 8BA) screws.


RA Loco Assembly Tips

Parts List


In addition to the 3D printed parts, the following parts must be obtained separately by the modeller:
  • Brass wire for handrails, etc. (0.4 mm, 0.6 mm)
  • Air hoses - e.g. Detail Associates #6206 (Vacuum brake hoses are included.)
  • Handrail Posts (4) for uncoupling levers - e.g. Markits 1.5 mm(short - available from Railwest Models.
  • Handrail Stanchions - see below.
  • Bogie drive mechanisms - see below (Hollywood Foundry)
  • Motor - Mashima 1833D Flat Can (double shaft, 2 mm diameter, includes fixing screws) (Hollywood Foundry)
  • Drive shaft(s) - 1.5 mm diameter, approx 65 mm long (cut to exact length) (Brass rod is suitable.)
  • Universal Joint set for 1.5 mm shafts (Hollywood Foundry)
  • Flexible coupling(s) for motor end(s) of drive shafts - suggestion is to use model aircraft fuel tubing, approx. 1 mm ID, 4 mm OD.  
  • DCC decoder and speaker (both optional)
  • Light Emitting Diodes (LEDs) for headlights 4 x 3 mm (sunny white)
  • Optic fibre 2 mm diameter for headlights.
  • LEDs (red and white) and optic fibre, if operating marker lights desired
  • paint as desired
  • decals - contact Westland Models.
  • lead or other weighting material
  • Kadee couplers #156 ("scale") or #146 (normal size)
  • Kadee draft gear boxes #252
  • Fixing screws for body, couplers and fuel tank e.g. Kadee #256 - 12 holes are included correct size (1.8 mm) ready for tapping 2-56.
  • Fixing screws for speaker M1.4 x 6 (slightly longer is OK) - 4 holes are included correct size (1.1 mm) and screws should make their own thread, tapping shouldn't be required.  Suitable screws are available from DCC Concepts - Part No. DCS-PHB156 or in assortment DCS-PHBSet.  Although described as 1.5 mm, the DCC Concepts screws are actually M1.4 thread.  Note:  DCC Concepts now supplies pan-head and countersunk screws interchangeably, so you can't be sure of getting one or the other.


Bogie Drive Mechanisms


The bogie drive mechanisms can be ordered direct from Hollywood Foundry. The ordering specifications are as follows:


Drive bogie specifications: G16.5/B28.6+25/W14-110/15:1DUALBELT/NOBOL

Dummy bogie specifications: G16.5/B28.6+25/W14-110/NOBOL

To order the above bogie configurations, please use the special order page on the Hollywood Foundry web site and copy and paste the above codes into the Product Description field.  

The modeller has the choice of fitting two identical drive bogies or one drive bogie and a matching dummy bogie, depending on the required hauling capacity.  

If a single drive bogie is fitted, this would normally be placed at the rear to keep the cab free for interior detailing if desired.  However, the drive shaft is quite low above the footplate level, so there is minimal intrusion into the cab when two drive bogies are fitted.

The current (December 2014) pricing for the required Hollywood Foundry parts is:

Drive bogie - $91.30 (same price as Bullant In-Line 3-Axle)

Dummy bogie - $45.10 (same price as Bullant 3-axle Dummy)
Motor: Mashima M1833D - $31.35

Universal Joint Set for 1.5 mm shafts (set contains parts for 4 joints.  1 joint is required per drive bogie, but it is recommended to purchase 1 set per loco to allow for some "spares".) - $4.19 per set

Drive shafts are available from Hollywood Foundry although the required 65 mm length is not a standard product. Check with Hollywood Foundry for availability.  Alternatively, 1.5 mm brass or steel rod can be used.

Silicone Tubing - used for flexible coupling between motor and drive shaft(s).  Supplied free by Hollywood Foundry if requested when ordering other parts.  Tubing will fit both 2 mm motor shaft and 1.5 mm drive shaft.

The prototype 3D-printed chassis showing central motor, Tsunami AT-style DCC sound decoder, drive shaft, belt drive and speaker "duct" with tunnel for drive shaft.
The chassis does not have provision for a flywheel.  The main reason is that the motor is mounted low down, partly in the fuel tank, to get a "straight line" drive shaft alignment.  Also, the speaker is very close to one end of the motor, which was necessary to avoid the narrow part of the body just behind the cab.


DCC and Sound


The chassis is specially designed to accept a 23 mm square high-bass speaker (Soundtraxx 810129 or equivalent) if a sound decoder is to be installed.  The speaker faces downwards on a "sound duct" which has a "tunnel" through it for the front drive shaft.

Although the choice of specific sound decoder is very subjective, the Soundtraxx Alco 244 Tsunami decoder sounds similar to the English Electric diesel engine in the prototype, and is probably the closest available "off-the-shelf" decoder.  The Tsunami "AT" style decoder model 828043 (pictured above) is suitable and slightly cheaper than the TSU-1000 style model 827104.

Note: The above links are for the SoundTraxx web site.  SoundTraxx do not sell direct but their products are available from many retailers.


Couplers


The suggested couplers are both "long shank" style which avoids the problem of the "glad hand" on opposing couplers from fouling the cowcatcher.  The choice between normal and "scale" size is up to the individual modeller.

Also, the suggested Kadee #252 draft gear boxes should be mounted upside down (as per the photo on the right on the Kadee web site). The round boss on the upper side needs to be trimmed away to allow the assembled coupler to slide into the headstock opening.

Other types of couplers can potentially be installed by modifying the headstock and/or coupler mounting pad.


Handrails


Unlike the chain handrails on the R class, the RA had solid handrails but with removable segments to allow the doors to be opened.

The 3D-printed chassis incorporates holes approx. 0.6 mm diameter to house the vertical handrail posts, typically cut from 0.6 mm brass wire.

One option for the handrails is to solder each section of handrails from 0.6 mm brass wire.  Marbelup Models can supply a PDF template for the handrails on request.  Note that the end walls of the cab have starter holes for the horizontal handrails.  These should be carefully opened out with a 0.65 mm drill bit to a depth of approx. 1.5 mm.


Use of A-Line Handrail Stanchions


An alternative, which is potentially easier than soldering, is to use preformed steel handrail stanchions available from A-Line (Division of Proto-Power West, USA).  These are available from various online hobby shops and/or eBay.  (Marbelup Models has limited stocks of these stanchions available at $15 per pack of 35 stanchions.)

A-Line Handrail Stanchions
Although these stanchions are intended for HO locos, the two longest sizes are sufficiently long to be trimmed to the correct length for the RA.  The A-line part numbers are D1071 (long) and D1071 (extra long).  The stanchions should be trimmed at the bottom to a length of 18.5 mm, measured from the top of the "loop".  For the handrails on the end platform, the stanchions should be trimmed to 17.5 mm.  After trimming, file off any rough edges from the cut end.  A total of 28 stanchions is required.

The holes in the 3D-printed chassis should be carefully drilled out to 0.75 mm to accommodate the stanchions (suggested drill size - test on some scrap plastic first).  Carefully insert each stanchion vertically into the drilled hole, taking care to align the loop perpendicular to the sides of the loco.  It is also suggested to orient all stanchions the same way, e.g. with the open side of the top loop inwards.  Make sure the bottom of each stanchion is level with the underside of the running boards.

Once the stanchions are installed, 0.6 mm brass wire can be threaded through the line of stanchions to complete the handrail.  

Where the handrails join onto the cab, there is a second, short handrail half-way up (See prototype photos.).  If desired to replicate this feature, a short length of brass should be soldered onto the inside of each stanchion nearest the cab.  Experience suggests the stanchions require light filing before soldering.

Once all the stanchions are in place and the long handrails threaded through, check that all the stanchions are vertical and make any necessary adjustments.  Then, the brass handrail can be secured to each stanchion with superglue and, if desired, the stanchions glued into the holes in the running boards.  Note that the short handrail in front of the cab (right side of loco only) should not be glued as it needs to be removed prior to separating the body and chassis, e.g. for maintenance.

Chassis - Removal of Support Material

Carefully cut away the support materials from the delicate areas highlighted in the drawing below which are:
  • Bolsters with bogie chain brackets approx. 6 mm in from edge of footplate (2 per side)
  • Triangular footplate supports (4 per side)
  • Sandboxes (2 per side)


Once these areas have been done, the remainder of the support material can be gently torn away by wiggling a section of it to break the fine attachment points.  

The remnants of the support attachment points should be removed with a sharp hobby knife, filing or sanding on all visible areas, including the bogie attachment points.

Chassis Height


The finished height of the footplate should be 23 mm.  Spacers with a nominal thickness of 1 mm are required between the Hollywood Foundry bogies and the underside of the footplate.  The thickness of the spacers can be varied slightly, if required, to adjust the coupler height to match a Kadee coupler height gauge.

Headlights

The holes provided in the body shell for headlights are nominally 2.5 mm diameter, but typically slightly undersize due to the 3D printing process.  

One method of lighting the headlights is to use a short length of optic fibre together with a 3 mm LED (Light Emitting Diode).  

Note: Incandescent (filament) lamps are not recommended due to their high operating temperature which may damage the 3D print material.

At the rear of the loco, it is not practical to drill out the headlights to allow use of 2.5 mm diameter optic fibre, as the hole provided follows a curved path to allow for the high position of the headlights relative to the roof of the long hood.  The suggested method is to carefully drill out the first 2-3 mm of the hole to 2.5 mm diameter, but use 2 mm diameter optic fibre which can bendto match the curved shape of the hole.  The end of the optic fibre can be flared to approx. 2.5 mm diameter by holding it close to (but not touching) a hot soldering iron.  With a little practice, the amount of flare can be judged to give a lens shape 2.5 mm in diameter.  The same technique can be used for the front lights as well to avoid the need to purchase two difference sizes of optic fibre.

To attached the LED to the optic fibre, 3 mm black heatshink tubing is recommended.  With the use of a hot air gun, the heatshrink tubing will shrink to form a snug fit over the optic fibre.  However, the hot air may well be hot enough to melt the plastic optic fibre, so the trick is to shrink the tubing over the shank of a 2 mm drill bit, them slide the drill bit out and slide in the optic fibre.

Typical steps are:

  1. Cut heatshrink tubing to length, e.g. 8-10 mm.
  2. Hold 3 mm LED in a small vice by its legs, with the clear lens uppermost.
  3. Push the cut length of heatshrink tubing over the clear lens of the LED.
  4. Hold the shank of a 2 mm drill bit inside the heatshrink tubing while applying heat from a hot air gun.
  5. When it has cooled, withdraw the drill bit and insert the desired length of optic fibre.  For the rear of the loco, you will probably have to feed the non-flared end of the optic fibre through the curved hole provided (from the outside) and attached the LED with attached heatshrink tubing on the inside.

For the dual headlights, it is simplest to wire the two LED in series as this simplifies the wiring and avoids the need for two separate resistors.  A resistor of around 2K2 (2,200 ohms) is a suggested starting point for LEDs powered from DCC decoders.

Saturday, 27 September 2014

NH ENH QA HA Hopper Wagon Assembly Tips

TT3 (left) and S scale models with supports attached.

Removing Support Structures


Carefully remove the support structure from the wagon.  It is suggested to use a sharp knife to cut the supports away from visible areas.  Take particular care around the end steps and the ends of the hopper doors where there are fine pull rods.

Note:  Sometime, contrary to instructions, i.Materialise remove most of the support structures in the factory.  Marbelup Models prefers that the supports structures are left attached in the factory as they help protect delicate parts of the models during handing and shipping.

Once the majority of the support structure has been removed, carefully go over the wagon and cut away the small supports which typically extend from one part to another, for example, around the door operating mechanism and other detail items.  An Exacto type hobby knife with a sharp pointed blade (Exacto #11 or similar) is quite useful for getting into the nooks and crannies.  For some parts, e.g. around the door actuating mechanism, where even a fine knife blade won't reach, a piece of wire (e.g. 0.8 mm spring steel wire) can be used to push against the support attachments and break them off.  Another option is to sharpen the end of the spring steel wire to a chisel point, and secure the wire in a pin vice to form a tiny chisel.

Go over the model and smooth off any remnants of the fine supports, expecially in the visible areas.  A sanding stick or small file can be useful for this.  A hobby knife with a chisel type blade (Exacto #17 or similar) can also be useful for smoothing flat areas, such as the underside of the underframe,

Bogie and Coupler Mounting Holes


For HO and larger versions, the mounting holes for the couplers and bogies have been printed at 1.8 mm diameter to suit 2-56 or 8BA screws.  Clear out the holes with a 1.8 mm drill in a pin vice, but it is preferable to NOT drill through the floor to avoid the screws being visible on the finished model.

The coupler mounting holes for the HO version do go right through the floor due to the limited material thickness available.  The holes should be tapped for HO versions only.

For S and O scale verions, the mounting holes are "blind".  Due to the difficulty of tapping the blind holes, the 3D print includes vertical grooves in the sides of the holes to help the screws cut their own threads, so tapping the holes is not required nor recommended.

Grooved holes used for S and O scale versions.  Tapping is not required for these holes.
For TT3 versions, the mounting holes for the couplers and bogies have been printed at 1.2 mm diameter to suit the size 0-48 screws typically supplied with Kadee HOn3 couplers.  These holes should be cleaned out with a 1.2 mm drill but don't need to be tapped.

Bogies


Various options are available for bogies for the different scales.  Some packing will most likely be required, depending on the bogies used, to achieve the correct wagon height above rail level.

TT3n½ Scale (10.5 mm gauge)

MicroTrains HOn3 Bettendorf bogies #00502020 were used on the Marbelup Models test model and fit well, although they represent an early 20th century design rather than the more usual mid-20th century Bettendorf style.

Blackstone Models HOn3 Bettendorf Trucks #B370110 are potentially suitable, but have not been tried.

HOn3½ Scale (12 mm gauge)

Marbelup Models used Wuiske Models QRB008 Modern QR bogies on test models.  They fit the NH and ENH models but don't suit the Tasmanian QA.HA version as they are fairly long wheelbase and the inner wheels foul the extra door stop parts.

Caintode Flats produce a range of bogies for QR and Tasmanian models, and the shorter wheelbase Bettendorf style bogies may be suitable, but have not been tested.

Sn3½ Scale (16.5 mm gauge)

The bogie mounting points are designed to be 10 mm above rail level.  Depending on the bogies used and the height of their bolsters, it may be necessary to add washers or similar so that the coupler mounting surface is 11.5 mm above rail level.

Marbelup Models has 3D-printed bogies of the correct design for the WMC/WMD available for sale which are pretty close for this model.  Please refer to the WMC/WMD Assembly Tips for more information on these bogies.

Similar bogies, although of slightly different shape, are available from Black Diamond Models in Queensland.  The Black Diamond bogies are cast in white metal and are supplied fully assembled with wheels.

Marbelup Models WMC/WMD Bogie

On3½ Scale

Marbelup Models is not aware of any specific bogies which are available.  Potentially, On3 or S scale standard gauge bogies could be suitable.  Also, the Marbelup Models 3D-printed bogies for the WMC/WMD hopper wagon could potentially be printed in O scale, depending on the availability of suitable wheelsets.

Couplers


As with bogies, there are various coupler options depending on the scale of the model.  Because the models are 3D-printed "on demand", it is possible to customise the coupler mountings to suit specific requirement of individual modellers.

TT3n½ Scale

The TT3 version is currently designed to suit Kadee #711/#712 HO 3/4 size couplers set at a height of 7.8 mm to match the prototype coupler height.  These couplers are the same as Kadee #713/#714 HOn3 couplers, other than having a longer trip pin to suit HO standard gauge models.  For TTn3½ use, the trip pin on the #711/#712 will need to be shortened by about 2 mm to match the 7.8 mm coupler height.

Kadee #713/#714 couplers can also be used at the intended HOn3 height, which requires a shim of approx. 0.6-0.7 mm to bring the couplers down to the HOn3 height (7.14 mm).

HOn3½ Scale

The HO models are designed for Kadee HO "whisker" couplers at the HO standard gauge height (9.9 mm).  Either the #158 (scale size) or #148 (normal size) couplers can be used, with #262 draft gear boxes.

The draft gear boxes supplied with the couplers do not fit as they have a different mounting hole position.  The #262 draft gear boxes are narrower and have been used because they provide more clearance for narrow gauge wheelsets.  Also, the #262 draft gear boxes are easier to use as the lid snaps into position.

Note that the height from rail level to the coupler mounting surface should be 11.5 mm, the standard for Kadee HO couplers.

Sn3½ Scale

The S models are designed for Kadee HO "whisker" couplers at the HO standard gauge height (9.9 mm).  Either the #158 (scale size) or #148 (normal size) couplers can be used, with #242 draft gear boxes which are the ones normally supplied with the whisker couplers.  The reason for using the #242 draft gear boxes is that the mounting screws are closer to the end of the wagon (compared to #262 boxes) to avoid a clash with the outer axles.

Note that the height from rail level to the coupler mounting surface should be 11.5 mm, the standard for Kadee HO couplers.  The 2-56 6.35 mm (1/4") long screws commonly used for couplers are slightly too long for the blind holes.  Options are to shorten the screws by 0.5 to 1 mm, or to add a flat washer between the head of the screw and the coupler.  Railwest Models sells suitable washers with a 2.2 mm hole diameter.

On3½ Scale (1:48 and 7 mm scale)

The 7 mm scale model is design for the Kadee #805 O Scale couplers or other Kadee couplers with the same mounting holes.  If requested, the 1:48 scale model can also be configured for these couplers.

Handrails and Brake Handle


Small starter holes have been provided to locate the L-shaped handrails on each end.  One end also has a brake handle.  These parts can be formed from brass wire and fixed in position with superglue.  The hole for the vertical leg of the handrail is located near the corner of the underframe, and the hole for the horizontal leg is located just above the second rung of the ladder.  Carefully drill out the starter holes - see below for drill sizes.

The suggested wire sizes and dimensions for the handrails for each scale are as follows:

TT3: 0.4 mm wire, 0.45 mm drill, horizontal: 4.5 mm, vertical: 8.5 mm
HO: 0.4 mm wire, 0.45 mm drill, horizontal: 5.5 mm, vertical: 9.5 mm
S: 0.6 mm wire, 0.65 mm drill, horizontal: 7.5 mm, vertical: 12.5 mm
O 1:48: 0.8 mm wire, 0.85 mm drill, horizontal: 10 mm, vertical: 16.5 mm
O 7 mm: 0.8 mm wire, 0.85 mm drill, horizontal: 11 mm, vertical: 18.5 mm

Note:  The above measurements are a suggested starting point.  Feel free to make adjustments as required.

Handrail and Brake Handle

The brake handle is also an L-shape, with the shorter, horizontal portion fitting in a hole just above the centre of the handbrake mechanism.  The suggested wire and drill sizes and dimensions for each scale are as follows:

TT3: 0.4 mm wire, 0.45 mm drill, horizontal: 1.5 mm, vertical: 6 mm
HO: 0.4 mm wire, 0.45 mm drill, horizontal: 2 mm, vertical: 7 mm
S: 0.4 mm wire, 0.45 mm drill, horizontal: 2 mm, vertical: 9 mm
O 1:48: 0.4 mm wire, 0.45 mm drill, horizontal: 2.5 mm, vertical: 12 mm
O 7 mm: 0.4 mm wire, 0.45 mm drill, horizontal: 2.5 mm, vertical: 13 mm

Painting


Either enamel or acrylic hobby paints can be used to paint the finished model.  The test models have been painted with Revell Hobby Enamel No.83 "rust" which seemed a good match for the faded red/brown of the original NAR NH hoppers.

Monday, 15 September 2014

NH ENH QA HA AHAF Hopper Wagons

NH Hopper S Scale after Painting
This 3D design from Marbelup Models is a little different, in that it is of a wagon which didn't originate from WA although some did find their way to WA in 2003.

These wagons were originally built in 1966 and 1968 to carry iron ore on the North Australia Railway from the Mount Bundey and Frances Creek mines to Darwin.  In the late 1970's, they were relocated to Port Lincoln in South Australia for use on the Eyre Peninsular Railway, carrying superphosphate, ballast and, later, Gypsum.  Some were relocated to Tasmania to carry coal and superphosphate.  Then, in 2003, approx 20 were shipped across to WA and refurbished for use on the Mt Gibson iron ore trains to Geraldton.

So, it seemed a good opportunity to build a model of these wagons which have served in 4 states/territories for well over 30 years, all on the 3' 6" (1067 mm) narrow gauge.  At this stage, Marbelup Models has done the 3D design for the original NT, SA and Tasmanian versions.  We will consider the WA AHAF version is there is any interest from modern image modellers.

NH Hopper TT Scale after Painting
The photos, below, of the unpainted models include added handrails and brake handles formed from brass wire.  Starter holes are included in the 3D print for the wire details.  See assembly tips for more information on finishing and detailing.

NH S Scale, Unpainted, A End

NH S Scale, Unpainted, B End
Original NH/NHA as running in Northern Territory 
NH/NHA "late" version as running in Northern Territory and also in
South Australia circa 1978-1984, prior to entering gypsum traffic.
QA and later HA as running in Tasmania
ENH/ENHA as running in gypsum traffic in South Australia.
The ENH/ENHA is also available with brackets for hungry boards, but without hungry boards.
AHAF as running to Geraldton, WA

RB Open Wagon Construction Tips

Removal of Support Structure


In general, it is best to first cut away the supports from the areas which have small details, and the areas which will be visible on the the finished model with a sharp hobby knife.  (An X-Acto style knife with a #11 fine blade can be useful for the fiddly bits.) Take particular care removing the supports from the brake handles, queen posts, door bumper strips, vacuum hoses and underfloor brake gear.

The brake handles have "sacrificial" guards around them to provide some protection against breakage during production and shipping of the 3D printed model.  It is suggested to leave these in place until most of the other work has been done to minimise the risk of breakage to these delicate parts.

Once the supports have been cut away from the delicate areas, the remaining supports can be broken away by wiggling them or applying pressure to break the small attachment points.

Non-Tapping Holes


The holes for the couplers and bogies are designed to accommodate 2-56 or 8BA screws without tapping.  This also has the advantage that the screws remain tight, so they won't accidentally work loose (especially for the bogies).

Note:  Tapping the holes is not recommended as it will remove more material and potentially lead to stripped threads.

Bogies


Railwest Models sells suitable arch-bar bogies.

If necessary, adjust the height of the wagon on the bogies so that the coupler mounting surface is 11.5 mm above rail level.

Couplers


The VG is designed for Kadee "whisker" couplers.  Either the #158 (scale size) or #148 (normal size) couplers can be used, with #262 draft gear boxes.

The draft gear boxes supplied with the #148 and #158 couplers do not fit as they have a different mounting hole position.  The #262 draft gear boxes are narrower and have been used because they allow details such as the brake hoses to be positioned the scale distance from the wagon centre line.  Also, the #262 draft gear boxes are easier to use as the lid snaps into position.

Note that the height from rail level to the coupler mounting surface should be 11.5 mm, the standard for Kadee couplers.

Handrails


Handrails can be formed from 0.4 mm brass wire.  Starter holes are provided on the ends, which should be opened out with a 0.45 mm or 0.5 mm drill bit.

The lengths of the end handrails (centre to centre) is 4.5 mm.  Once in position, the handrails and other brass details can be secured with Super Glue.

Truss Rods

The RB has four truss rods which can be formed from 0.6 mm brass wire.  The diagram below gives the dimensions for bending the truss rods.  The longer truss rods are on the outside of the wagon.

The anchor points on the underframe for the ends of the truss rods have preformed holes which should be drilled out with a 0.65 or 0.7 mm drill bit.



Brake Rods


There are a total of 5 brake rods which can be formed from 0.4 mm brass wire.  Starter holes are provided which should be opened out with a 0.45 mm or 0.5 mm drill bit.

Two long brake rods go from the handbrake lever at each end to the main brake shaft near the centre of the wagon.  Because the main brake shaft is offset slightly from the wagon centre line, the length of these rods is 63 mm and 58.6 mm, not including a right angle bend of approx. 1 mm at each end.  The bogie bolsters include holes though which these long brake rods can be threaded.

The other three brake rods are near the wagon centre line and represent the rods which, in real life, connect to the brake rigging on the bogies.  At the left end, as pictured above, the brake rod should be 49.5 mm long, not including a right angle bend of approx. 1 mm at one end only.  The other end attaches to a hole near the bogie pivot point.

At the right end, there are two rods which are connected via an intermediate lever.  The first is 29.2 mm long not including right angle bends of approx. 1 mm at each end.  The second rod is 26 mm long with a right angle bend at one end only, the other end attaching to a hole near the bogie pivot point.

Tuesday, 3 June 2014

RB Open Wagon

The steel-sided RB open wagons were built between 1930 and 1937, with a total of 177 being built.  Some RB's lasted until 1971 in their original form.  Others were converted, quite early on, to class RBW by the addition of wooden hungry boards to increase the capacity for carrying wheat.  The RBW version survived until 1990.  For more information on the prototype, refer to the WA Wagon Pages.

Prototype Photo from Rail Heritage WA
The model depicts the original version.  As well Marbelup Models plans to produce the RBW version in the future.  The 3D-printed one-piece body incorporates many details including brake cylinder, brake levers, queen posts and bumper springs for the drop-down doors.  The modeller must add some details from brass wire including truss rods (4), brake rods and handrails (s).  The interior of the model includes detail to represent the pressed steel end panels and doors.

The 3D print includes full rivet detail - 1024 rivets in total!


Correct arch-bar bogies are available from Railwest Models.  The photo above shows the model with Ratio (UK) arch-bar bogies which are similar but have a slightly shorter wheelbase.

See the Construction Tips for details on installation of truss rods, brake rodding, etc. to complete this model.




Saturday, 29 March 2014

FD Van Construction Tips

"As Printed" with supports still attached.

Removal of Support Structure


The FD van is printed upside down, which results in the optimum surface finish on the louvres which are obviously the most prominent part of this model. The downside is that removal of the supports from the roof will leave small attachment points which require cleaning up, and there will be some visible stepping on the roof.

In general, it is best to first cut away the supports from the areas which have small details, and the areas which will be visible on the the finished model with a sharp hobby knife.  (An X-Acto style knife with a #11 fine blade can be useful for the fiddly bits.) Take particular care removing the supports from the brake handle, vacuum hoses, door tracks, and underfloor brake gear.  Note that there will probably be a tiny support at the top of each vacuum hose.

The brake handle has a "sacrificial" guard around it to provide some protection against breakage during production and shipping of the 3D printed model.  It is suggested to leave this in place until most of the other finishing work has been done to minimise the risk of breakage to these delicate parts.

Once the supports have been cut away from the delicate areas, the remaining supports can be broken away by wiggling them or applying pressure to break the small attachment points.  It is not necessary to remove all the supports from inside the van body as these will not be visible on the finished model.

The visible stepping on the roof can be smoothed of using a craft knife with a scraping action, then finished with sanding stick or sandpaper.  Any minor indentations should be filled with modelling putty (e.g. Tamiya) and sanded smooth.

Take care when scraping/sanding the roof to not damage the rain strips.  It may be helpful to make a concave, curved sanding tool using a segment of cardboard mailing tube or plastic pipe, with sandpaper attached with glue or double sided tape.  The radius of the roof is 33.3 mm so, ideally, the sanding tool should have a similar radius.

Sanding tool for roof, with handle from scrap wood.

Couplers


The FD is designed for Kadee "whisker" couplers.  Either the #158 (scale size) or #148 (normal size) couplers can be used, with #262 draft gear boxes.

The draft gear boxes supplied with the #148 and #158 couplers do not fit as they have a different mounting hole position.  The #262 draft gear boxes are narrower and have been used because they allow details such as the brake hoses to be positioned the scale distance from the van centre line.  Also, the #262 draft gear boxes are easier to use as the lid snaps into position.

Note that the height from rail level to the coupler mounting surface should be 11.5 mm, the standard for Kadee couplers.

The holes for the couplers are designed to accommodate 2-56 or 8BA screws without tapping.  

Note:  Tapping the holes is not recommended as it will remove more material and potentially lead to stripped threads.

W-Irons


The design of the FD van is optimised to suit the "closed" W-irons, made from etched brass, which are available from Railwest Models.  This is because the closed W-irons, when used in conjunction with Markits brass bearings, are the correct width for wheels with 26 mm axles, so that the sides of the W-irons are truly vertical.  (Refer to Sn3½ Blog article for more details.)  Other W-irons can be fitted with minor adjustments.

The mounting height for the W-irons is optimised for wheels of the correct scale diameter, i.e. 12.5 mm diameter.  If using the commonly available wheels of 12 mm diameter, packing pieces of approx. 0.25 mm will be necessary between the W-irons and floor.


"Closed" (left) and "Open" W-irons.  Photo courtesy of Railwest Models
Remove the W-irons from the fret, fold them up and fit brass bearings in the usual way.  If using compensation with the "closed" W-irons, the rocking W-iron is at the extreme left of the photo above, with the fixed W-iron adjacent to it on the same fret.

The underframe of the wagon includes eight small holes at each end for mounting the W-irons, using 1 mm x 3 mm pan-head self tapping screws.  Different sets of holes are used at each end, depending on the type of W-iron used, and each W-iron requires only two screws.  (These screws are available from DCC Concepts part no. DCS-PH103.)  

(Of course, you can glue the W-irons in position if you prefer, in which case the holes and grooves included in the underframe help to locate the W-irons in the correct position.)

The fixed W-iron is installed at end of the wagon opposite the brake handle.  Use the fixing holes which are located on the axle centre line, 15 mm apart, to fix the W-iron into position.   If using 26.5 mm wheels, the wheel flanges will most likely rub on the screw heads, in which case the W-iron should be glued in position (e.g. with super glue or Pliobond).  Screws can be used to locate the W-iron and hold it in position until the glue has dried.

To achieve compensation, the rocking W-iron is installed at the end of the wagon with the brake handle.  Remove the separate pivot bracket from the centre of the W-iron and fold up the ends to match the etched holes in the W-iron.  It may be necessary to bend the ends of the brackets slightly more than 90° to minimise slop in the rocking W-iron.  The idea is to use the holes in the pivot bracket to secure the rocking W-iron to the wagon, using the pair of holes on the wagon centre line spaced 10 mm apart.  To allow clearance for the screw heads, file or grind a hollow in the side of the W-iron.

As per the intended W-iron assembly procedure, pass a piece of brass wire (e.g. 1 mm diameter) through the pivot bracket and the corresponding holes in the side of the W-iron, and solder the wire on the outside only to the pivot bracket.  Check that the W-iron can move freely with respect to the pivot bracket.  Cut the centre of the brass wire out, to allow access for the fixing screws.  Cut the wire initially at a 45° angle to avoid forcing the sides of the W-iron apart, then cut the remaining section out leaving just enough to form the pivots for the rocking action.  Also trim the excess wire from the outside of the W-iron, and file the wire and solder until it is almost flush with the sides of the W-irons to allow it to be slid sideways between the brake shoe supports.

Fit the wheels (26 mm axle length) and check that wagon sits at the correct height above the rails, i.e. the coupler mounting surfaces should be 11.5 mm above rail level, and adjust if necessary.

After checking that the wagon runs happily, fit the cosmetic W-iron/axlebox assemblies to the outside of the brass W-irons.  It will probably be necessary to clean out the holes in the W-iron/axlebox assemblies with a 2 mm (or slightly larger) drill bit to fit over the brass bearings.

Handrails


Handrails can be formed from 0.4 mm brass wire.  Starter holes are provided on the side and ends, which should be opened out with a 0.45 mm or 0.5 mm drill bit.

The lengths of the handrails (centre to centre) are as follows:
  • doors: 9 mm
  • ends (vertical, above brake handle and shunter's step): 6.5 mm
Once in position, the handrails can be secured with Super Glue.

Floor and Weighting


To allow the van to be 3D-printed in one piece, the underframe is a skeleton only, with no floor.  If desired, rectangles of styrene (approx 1 mm thick) can be cut and glued between the underframe cross members to represent the floor.  Optionally, some or all of these pieces can be cut from sheet lead to add weight to the van.  

With no additional weight, the finished FD weight approx. 46 grams.  The suggested weight for a van of this length is approx. 68 grams (See Sn3½ Blog.).

The dimensions of the "floor" pieces are as follows:
  • Centre: 11.5 x 10.5 mm 
  • End: 12 mm x 6 mm 
Some of the pieces may require slight trimming around small details.  Because the vacuum cylinder occupies one of the "squares" near the centre of the wagon, lead weights should be applied to diagonally opposite "squares" to maintain equal weight on either side.  The unused "square" can be filled with styrene sheet if desired.

Tuesday, 11 March 2014

VDR Bogie Freezer Van


A total of five VDR vans were converted from VD louvre vans between 1956 and 1962.  The later ones only had a single door to the freezer compartment and one of the early vans was later converted to the single door arrangement.  (Marbelup Models may produced the single door version if there is sufficient demand.)


The refrigeration equipment was removed from the vans in 1970 after which they remained in traffic as general good vans, and were written off in the 1980's.

The photo below, from Rail Heritage WA, shows a prototype VDR van.



Refer to the WAGR Wagon Pages for more information on the prototype.

The body of the VDR has been printed in one piece.  The print orientation has been chosen to optimise the definition of the louvres, which will result in some visible stepping on the roof, which can be smoothed off by scraping and/or sanding.  As well, the modeller will be required to remove the support materials from the 3D printing process, and add various details such as handrails, from brass wire (not supplied).  For more information, please refer to the Construction Tips for VD Van which is very similar.

A set of decals for the van will be available from Westland Models (email: clarkrb@iinet.net.au).

Thursday, 27 February 2014

VD Van Construction Tips

VD Van "as printed" with supports still attached

Removal of Support Structure


The VD van is printed upside down, which results in the optimum surface finish on the louvres which are obviously the most prominent part of this model. The downside is that removal of the supports from the roof will leave small attachment points require cleaning up, and there will be some visible stepping on the roof.

In general, it is best to first cut away the supports from the areas which have small details, and the areas which will be visible on the the finished model with a sharp hobby knife.  (An X-Acto style knife with a #11 fine blade can be useful for the fiddly bits.) Take particular care removing the supports from the brake handles, vacuum hoses, door tracks, and underfloor brake gear.  Note that there will probably be a tiny support at the top of each vacuum hose.

The brake handles have "sacrificial" guards around them to provide some protection against breakage during production and shipping of the 3D printed model.  It is suggested to leave these in place until most of the other work has been done to minimise the risk of breakage to these delicate parts.

Once the supports have been cut away from the delicate areas, the remaining supports can be broken away by wiggling them or applying pressure to break the small attachment points.  It is not necessary to remove all the supports from inside the van body as these will not be visible on the finished model.

The visible stepping on the roof can be smoothed of using a craft knife with a scraping action, then finished with sanding stick or sandpaper.  Any minor indentations should be filled with modelling putty and sanded smooth.

Non-Tapping Holes


The holes for the couplers and bogies are designed to accommodate 2-56 or 8BA screws without tapping.  This also has the advantage that the screws remain tight, so they won't accidentally work loose (especially for the bogies).

Note:  Tapping the holes is not recommended as it will remove more material and potentially lead to stripped threads.

Bogies


Railwest Models sell suitable bogies.

An alternative is American Models S Scale standard gauge Bettendorf bogies which can be regauged to Sn3½ as described on the Sn3½ Blog. (Marbelup models has 3D-printed replacement bolsters available which simplify regauging of the American Models bogies.)

If necessary, adjust the height of the van on the bogies so that the coupler mounting surface is 11.5 mm above rail level.

Couplers


The VG is designed for Kadee "whisker" couplers.  Either the #158 (scale size) or #148 (normal size) couplers can be used, with #262 draft gear boxes.

The draft gear boxes supplied with the #148 and #158 couplers do not fit as they have a different mounting hole position.  The #262 draft gear boxes are narrower and have been used because they allow details such as the brake hoses to be positioned the scale distance from the van centre line.  Also, the #262 draft gear boxes are easier to use as the lid snaps into position.

Note that the height from rail level to the coupler mounting surface should be 11.5 mm, the standard for Kadee couplers.

Handrails


Handrails can be formed from 0.4 mm brass wire.  Starter holes are provided on the side and ends, which should be opened out with a 0.45 mm or 0.5 mm drill bit.

The lengths of the handrails (centre to centre) are as follows:
  • doors (2 per side): 9 mm
  • ends (above brake handle): 6.5 mm
Once in position, the handrails and other brass details can be secured with Super Glue.

Brake Pull Rods and Hangers



On each side, there is a brake pull rod which can be formed from 0.4 mm brass wire.  Starter holes are provided which should be opened out with a 0.45 mm or 0.5 mm drill bit.  On the brake gear hanger nearest the vacuum cylinder, support the underside of the small lever from the inside when drilling to avoid braking the small lever.  The distance (centre to centre) between the holes is 45.4 mm.

The hangers for the brake pull rods can be formed from brass ministrip 0.8 mm x 0.25 mm (made by North Yard NZ and available from Railwest Models).  Small slots have been provided in the underside of the door track for attaching the top end of the brake hangers.  The brass ministrip should be cut to lengths of 11 mm and 13.5 mm, with 2 mm at the bottom bent over to form a loop to support the brake pull rod.  (Refer to prototype photos for arrangement.)

Floor and Weighting


To allow the van to be 3D-printed in one piece, the underframe is a skeleton only, with no floor.  If desired, rectangles of styrene (approx 1 mm thick) can be cut and glued between the underframe cross members to represent the floor.  Optionally, some or all of these pieces can be cut from sheet lead to add weight to the van.  

With no additional weight, the finished VD with American Models (plastic) bogies weight approx. 75 grams.  The suggested weight for a van of this length is approx. 110 grams (See Sn3½ Blog.).

Moving from the centre of the van towards the end, the dimensions of the "floor" pieces are as follows:
  • Centre: 20.25 x 14.5 mm (2 required)
  • Centre + 1: 20.25 x 14.5 mm (2 required)
  • Centre + 2: 22 x 14.5 mm (4 required)
  • End: 25 mm x 14.5 mm (4 required)
Some of the pieces may require slight trimming around small details.


SXT Construction Tips

SXT with added details, ready for painting.

Removing Support Structures

Carefully remove the support structure from both parts of the wagon.  It is suggested to use a sharp knife  carefully cut the supports away from the roof, ends, and the underframe.  Take particular care around the brake handles, brake hoses and brake rigging on the underframe.  The ends of the brake handle have a "sacrificial" guard to reduce the risk of breakage during production and shipping.  You may wish to leave the guards in place until the majority of the assembly work has been complete to minimise the risk of breakage.

Because of the fine ribbing on the brake hoses, the 3D printer's automatic software has generated many support points, which have merged into one.  Carefully cut between the brake hose and the support structure, using repeated cuts with a sharp knife (e.g. Olfa snap-off blade type or X-Acto knife with #11 blade), to separate the support structure, then carefully trim the remnants from the hose.

Interlocking Parts (CXB shown, but SXT is the same)
Note that on the underside of the roof, alternating ribs extend a short distance beyond the edge of the roof to interlock the two parts when it is time for final assembly.  

The support structure extends inside the upper and lower decks of the wagon to support the inside of the wagon sides.  From the outside, cut through supports attached to the small circular brackets for the horizontal wires above the side planking on each deck, on the underside of the roof, and the underside of the middle floor.  When you have cut as many of these supports as possible from the outside of the wagon, gently wiggling the supports structure (e.g. with needle nose pliers) from the open side, will break the remaining supports and allow pieces of the structure to be torn away. Be careful not to apply excessive force to avoid damaging the side planks and door areas.

Once the majority of the support structure has been removed, carefully go over both parts and cut away the small supports which typically extend from one part to another, for example, around the brake rigging and between the frame members of the underframe.  An X-acto type hobby knife with a sharp pointed blade (Exacto #11 or similar) is quite useful for getting into the nooks and crannies.

Go around the surfaces of each part where they will join together, and smooth off any remnants of the fine supports, on the roof, ends, middle and lower floors, etc.  A sanding stick or small file can be useful for this, but be careful not to damage the projecting parts which are designed to interlock.  Also remove any remnants from the very ends of the projecting parts.  When you think you have finished, test fit the two halves together.  Interlock the roof ribs first, then gently bring the underside of the wagon together to see how it fits.  There are several frame members in the underframe which have retangular pins which fit into oval holes in their opposite number (a variation on the square peg in the round hole concept). 

If the two halves don't close completely, dismantle again and check for and remove any tiny bumps from the support structure attachments.

Near each end of the wagon and in the centre, there are four small tabs designed for 1 mm x 3 mm long pan-head self tapping screws, to secure the two halves of the wagon together.

In the long term, you have the option of gluing the body together, e.g. with superglue, or continuing to use the screw fixings..

Non-Tapping Holes


The holes for the couplers and bogies are designed to accommodate 2-56 or 8BA screws without tapping.  This also has the advantage that the screws remain tight, so they won't accidentally work loose (especially for the bogies).

Note:  Tapping the holes is not recommended as it will remove more material and potentially lead to stripped threads.

Adding Wire Detailing


(CXB wagon shown, SXT is similar.)
Several lengths of 0.4 mm brass wire are required as follows:
  • A - 59.5 mm, above timber side rails, 8 pieces per side
  • B - 13.5 mm, above timber side rails, upper deck only, 4 pieces per side
  • C - 12 mm, upper doors, 4 pieces per side
  • D - 24 mm, lower doors, 4 pieces per side
  • E - 28.5 mm, upper door top guide, 2 piece per side
  • F - Brake pull rod, not required for SXT
  • G - 27.5 mm for centre linking section, 6 pieces per wagon (not shown in diagram)
The holes for the above have all been incorporated in the 3D-printed model.  Once in position, the various wire parts can be secured with super glue.

Wire "drill bit" in use for cleaning out holes in centre section.
The horizontal rods in the centre linking section are each secured by a hole in the centre vertical angle iron, and the ends sit in notches in the outer vertical angle irons.  Cleaning out the holes in the centre vertical angles requires a special technique, as the body of the wagon prevents use of a normal drill bit.  The suggested technique is to use a piece of 0.4 mm brass wire approx 75 mm long as an improvised drill but, by cutting one end at a 45 degree angle.  The rough edges of the cut end form a crude but effective drill bit when the wire is held in a pin vice.  To reach the centre holes, the end of the long "drill but" can be passed through the gaps between the side board and then through the gaps between the end boards.  If gently guided by tweezers, the wire "drill bit" will bend into a gentle curve to drill a fairly straight hole in the centre angle iron (See photo above.).  Once these holes in the angle irons have been cleaned out, the cut pieces of wire also have to be fed back through the slots in the end boards to allow inserting on the hole, then slid into their correct position.

Wire "drill bit" in use for cleaning out holes in doors. Note wires already inserted in centre section.
The holes for the horizontal rods above the side planks have a nominal diameter of 0.6 mm.  If a wire does not go in easily, do not force it.  Clean out the hole(s) with a 0.45 mm or 0.5 mm drill bit in a pin vice.  The holes for the wires in the doors and the upper door top guide are smaller, and will definitely need cleaning out with a 0.45 mm or 0.5 mm drill bit.  When cleaning out the holes in the doors on the left end of each side, the 75 mm long wire "drill bit" may also be useful as access to the holes in the doors is limited for a normal drill bit.

Also using 0.4 mm wire, form the 4 handrails which are located vertically on the ends of the wagon, above the brake lever, and also on the inner ends of each of the former CXB bodies.  The spacing between the holes is 6.5 mm.  

Bogies


Railwest Models sell suitable bogies.

An alternative is American Models S Scale standard gauge Bettendorf bogies which can be regauged to Sn3½ as described on the Sn3½ Blog.  (Marbelup models has 3D-printed replacement bolsters available which simplify regauging of the American Models bogies.)

If necessary, adjust the height of the van on the bogies so that the coupler mounting surface is 11.5 mm above rail level.

Couplers


The VG is designed for Kadee "whisker" couplers.  Either the #158 (scale size) or #148 (normal size) couplers can be used, with #262 draft gear boxes.

The draft gear boxes supplied with the #148 and #158 couplers do not fit as they have a different mounting hole position.  The #262 draft gear boxes are narrower and have been used because they allow details such as the brake hoses to be positioned the scale distance from the van centre line.  Also, the #262 draft gear boxes are easier to use as the lid snaps into position.

Note that the height from rail level to the coupler mounting surface should be 11.5 mm, the standard for Kadee couplers.

Brake Pull Rods and Hangers


(VG Van Shown - SXT brake arrangement is the same.)

On each side, there is a brake pull rod which can be formed from 0.4 mm brass wire.  Starter holes are provided which should be opened out with a 0.45 mm or 0.5 mm drill bit.  On the brake gear hanger nearest the vacuum cylinder, support the underside of the small lever from the inside when drilling to avoid braking the small lever.  The distance (centre to centre) between the holes is 44.5 mm.

The hangers for the brake pull rods can be formed from brass ministrip 0.8 mm x 0.25 mm (made by North Yard NZ and available from Railwest Models).  Small slots have been provided in the underside of the underframe for attaching the top end of the brake hangers.  The brass ministrip should be cut to lengths of 11 mm and 13.5 mm, with 2 mm at the bottom bent over to form a loop to support the brake pull rod.  (Refer to prototype photos for arrangement.)

Note: Due to the print orientation for the SXT, the slots in the underframe may be blocked by a tiny (0.5 mm diameter) support piece.  Test fit some brass ministrip in each slot - it should go in 2 mm.  If the slot is blocked, clear it with a fine knife blade, e.g. Xacto #11.

Weighting


With no additional weight, the completed wagon including wheels and couplers weighs around 98 grams.  The "desirable" weight for a wagon of this length (200 mm) is around 125 grams to ensure optimum operation including operation of Kadee couplers.

Addition of a Marbelup Models sheep load in Polyamide material adds approximately 32 grams, bringing the total weight up to around 130 grams. 

If modelling an empty wagon, the weight can be increased by gluing lead shot or sheet lead between the various frame members of the underframe, where it would not be seen in normal operation. 

Painting


Either enamel or acrylic hobby paints can be used to paint the finished model.  

If desired, the interior of the wagon can be painted (airbrushed) prior to assembly.  Experience to date suggests that this is probably not necessary as overspray from painting the outside tends to take away the "bare plastic" look on the inside surfaces.  

Obviously, if a sheep load is to be included, it should be added after spray painting the wagon itself. Tamiya XF-78 Wooden Deck Tan is a reasonable colour for the sheep load.

Once the wagon is completely assembled, the join line on the roof can be filled and smoothed off. The join lines on the ends are virtually invisible as they are aligned with the angle iron end braces.