Tuesday, 12 December 2017

WMC/WMD Construction Tips

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 brake hoses and end steps.

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 brake cylinders 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 around the brake cylinders 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.

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.

Bogie and Coupler Mounting Holes


The mounting holes for the couplers and bogies have been printed at 1.8 mm diameter to suit 2-56 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.

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.

Bogies


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 WMC/WMD Bogie
Marbelup Models has 3D-printed bogies of the correct design for the WMC/WMD available for sale.  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.

Assembly of 3D-Printed Bogies



The Marbelup Models WMC/WMD bogies are printed in two identical halves.  A set contains four pieces to make one pair of bogies.  As with other 3D printed parts, the first step is to removed the supports structure and clean up the small supports in the holes in the bogie sideframes, around the springs, etc.  Take care around the brake shoes to avoid breaking them.

The bolster section of each bogie half contains two holes intended for M1.4 screws (which are supplied with the bogies).  The larger hole nearest the narrow end of the bolster is a "clearance" hole and should be cleaned out with a 1.4 mm drill.  The smaller hole, nearest the bogie sideframe, should cleaned out with a 1.1 mm drill and tapped with an M1.4 tap.  (Drills and taps are available from North Yard in New Zealand.  The M1.4 tap is part No. 3014.  Refer to Page 5 of the North Yard Catalogue.)

An alternative to M1.4 screws is to use 1.5 mm x 6 mm self tapping screws, which are available from DCC Concepts - Part No. DCS-PH156.  If using self tapping screws, the smaller holes should be drilled out to 1.1 or 1.2 mm.  If the screws seem tight with 1.1 mm holes, try 1.2 mm, especially with bogies printed in Standard Resin (clear yellow rather than grey), which is somewhat less flexible.  The clearance holes should be drilled to 1.5 mm.

The bogie sideframes contain holes for fitting brass pinpoint bearings (available from Railwest Models).  These holes should be cleaned out with a 2 mm drill bit, after which the bearings should press fit into place.  The bogie is designed for 12 mm wheels with 26 mm axles.

When assembling the two halves, it may be necessary to trim the narrow end of the bolster by approx. 0.25 mm to get good alignment of the fixing holes and centre pivot hole.  (Later production will be made slightly shorter.)  After assembly, clean out the centre pivot hole with a 2.2 mm drill bit to suit 2-56 mounting screws.  (2.2 mm provides adequate clearance without excessive slop.)

Couplers


The WMC/WMD 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 WMC/WMD is also available with correct scale coupler height for WAGR/Westrail narrow gauge, in which case #252 draft gear boxes are used.

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 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.  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.  If using scale coupler height, the height to the coupler mounting surface should be 13.8 mm. 

Stiffening Rods


The WMC/WMD model includes provision for two metal rods to be inserted within the underframe structure to provide stiffness and guard against possible future warping of the plastic material over time.  Each of the transverse frame members includes two holes approx. 2.2 mm diameter, as part of the 3D print.

Location of stiffening rods
On the end sill, the hole for the stiffening rod is covered over by a 0.5 mm layer of plastic, opposite the handbrake assembly, as pictured below.  This can easily be drilled through for installation of the rod.  There is a corresponding hole on the diagonally opposite corner of the wagon.

Drill location for stiffening rod
The rods should be a maximum of 2 mm diameter and 140 mm long.  They can be of any strong metal, e.g. steel or brass.  One source of steel rod is threaded push-rods sold for radio controlled models by manufacturers such as Du-Bro, and available from many hobby shops.  These have a threaded section at one end, but the remainder of the rod is plain, about 1.85 mm diameter. Once the rod has been glued into position, the hole in the end sill can be filled with modelling putty and lightly sanded to restore the flat surface prior to painting.

Handrails


Small starter holes have been provided to locate the various handrails.

The WMC has just two handrails on opposite corners.  These can be formed from 0.6 mm brass wire.  Viewed from above, the handrail is an L-shape, with the horizontal portions about 6.25 mm long.  The height from the floor to the top of the handrail should be about 9.5 mm.  The vertical post nearest the coupler can be cut about 2 mm over-length to provide a secure (glued) fixing into the floor.  The vertical post near the side of the wagon should only be over-length by just 0.5 mm so the end of the wire is not visible from the side.

In addition, the WMD has 3 handrails on each end of the hungry boards.  Thinner brass wire, e.g. 0.4 mm should be used for these.  The hole centres for each handrail are 4.75 mm.  The WMD also has wire handrails/steps across the tops of the "chutes" at each end of the hopper.  The 3D print includes small notches for locating these, and the length of the wire should be 9.5 mm (8 required).

Note that the position of handrails and other details varies between different members of the WMD class.  The model depicts the most common arrangement, based on photos of various prototype wagons.

Door Lock Shafts


As part of the locking mechanism for the bottom discharge doors, there are two shafts which have to added using brass wire, either 0.5 or 0.6 mm.  The length of each piece of wire is 40 mm, although it is probably easier to feed a longer length of wire through the holes provided, then trim it to length with fine wire cutters after it has been glued into place.

Location of Door Lock Shafts

Brake Levers and Chains


The handbrake ratchet assembly on the end of the wagon includes a vertical groove to house a 10 mm length of 0.4 mm brass wire, to represent the handbrake lever.  Superglue is recommended for attachment of the wire.

A distinctive detail of the WMC/WMD are the chains running across the floor which connect the handbrake mechanisms with the brake linkage underneath the vacuum cylinders.  North Yard (NZ) make a suitable fine chain which is available from Railwest Models.

Threading the fine chain through the three guides at each end is a bit tricky.  It helps to use a piece of fine but soft wire as a "needle".  The 0.25 mm diameter inner conductor from "wire-wrap" wire used for electronics is suitable.  (If you ask nicely, you might be given a piece with your WMC/WMD!)  Once threaded through the guides, one end should be glued into the small notch provided for the purpose in the horizontal "angle iron" underneath the vacuum cylinder.  Once that end is fixed, the other end should be threaded through the support bracket for the handbrake which has a tapered keyhole-shaped hole.  When gently tensioned, the free end of the chain can be glued into the tapered hole to secure it, and the excess chain trimmed from underneath with fine wire cutters.

Weighting


With the Black Diamond (metal) bogies, the completed wagon weighs around 72 grams.  The "desirable" weight for a wagon of that length (140 mm) is around 95 grams to ensure optimum operation including operation of Kadee couplers.  (See the Sn3½ blog for more information.)

If requred, additional weight can be added by gluing lead shot or small pieces of sheet lead between the various frame members of the underframe, e.g. either side of the hopper doors, where it would not be seen in normal operation.

Painting


Either enamel or acrylic hobby paints can be used to paint the finished model.  The model pictured has been painted with Revell Hobby Enamel.

WSH/XM Ballast Wagon Instructions

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 steps and the handwheels underneath the side of the wagon.  Note that the steps have guards below them to protect them during production and shipping.  It is suggested to leave these guards in place until the majority of the finishing work on the wagon has been completed, to minimise the risk of damage during handling.

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 including, for example, inside the coupler housing.  An Exacto type hobby knife with a sharp pointed blade (Exacto #11 or similar) is quite useful for getting into the nooks and crannies.  

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.

Bogie and Coupler Mounting Holes


The mounting holes for the couplers and bogies have been printed at 1.8 mm diameter to suit 2-56 screws.  

Due to the difficulty of tapping 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.
Note: An economical source of 2-56 screws in various lengths is Little Bird Electronics.

Bogies


HO Scale - The suggested bogies are Kadee #569 or #1569, the only difference being the width of the wheels.  Both Atlas and Athearn make similar bogies, but the advantage of the Kadee ones is that they add some weight to the wagon due to the use of a relatively heavy plastic material.  Note that the depth of the blind holes is 3.4 mm for the HO model.  If using Kadee bogies, the supplied screws may need trimming to avoid damaging the floor of the wagon.

Sn3½ Scale - Marbelup Models makes specific bogies for the XM wagon, representing the prototype's standard gauge bogies with narrow gauge wheelsets.  The wheels should be larger than is normal for narrow gauge wagons.  Suitable wheels (14 mm diameter, 26 mm axles) are available from North Yard (NZ) and DCC Concepts.  Please note the gauge of the DCC Concepts wheels is slightly greater compared to  the NMRA RP25 standard, which can cause problems with the wheels "picking" point frogs.  It is suggested the DCC Concepts wheels be tested with your trackwork before purchasing in quantity.

The method of assembly for the bogies is the same as for the WMC hopper wagons except that the holes for the fixing screws are inclined at 10° above the horizontal so that the axles do not get in the way of the screwdriver.

Couplers


The WMC/WMD is designed for Kadee "whisker" couplers.  Either the #158 (scale size) or #148 (normal size) couplers can be used, with #262 draft gear boxes, although the normal size couplers are more appropriate.  Couplers are also available from Kadee in bulk packs without draft gear boxes.

The draft gear boxes supplied with the #148 or #158 couplers do not fit as they have a different mounting hole position.  The #262 draft gear boxes, which are available separately, 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.

For the HO model, the coupler fixing screws should be trimmed to about 3.8 mm so the top of screw is flush with the deck of the wagon.  One option is to use a metal 2-56 screw to form the thread in the plastic material, then use a Kadee Nylon 2-56 screw for the final installation, which is easier to cut to length.

Since mid 2017, the design for the XM has been modified so that the couplers are at the correct height for WAGR standard gauge, i.e. 13.75 mm (measured to the centre of the coupler).  Note that the corresponding height from rail level to the top of coupler mounting surface should be 15.4 mm.

If desired to fit couplers at the Kadee standard height for HO (9.9 mm), the couplers should be shimmed down by approx. 3.75 mm.  An alternative, is to use a Kadee "overset" coupler which reduces the height by approx. 1.25 mm, although a shim will still be required to match the HO coupler height.

Note that the prototype XM wagons retained their standard gauge coupler height.  When used with narrow gauge "chopper couplings", the wagons at the end of a rake were fitted with "gooseneck" couplers to reduce the coupler height.

Wire Details


There are quite a few details to be added from brass wire.  The following sequence is suggested:

Discharge Doors Mechanism


Note that the eight 4-spoke handwheels have been printed as part of the model.  In addition, some spares have been printed at the end of each of the discharge hoppers.  Carefully cut away the spare handwheels using a sharp knife, and retain in case of any breakages.  Smooth off any remnants of the attachment points on the ends of the hoppers.


The longitudinal shafts are shown in blue on the diagram above.  Suggested sizes are as follows:

  • HO, Outer Shafts: 0.6 mm wire, 25.75 mm long (4 required)
  • HO, Inner Shafts: 0.6 mm wire, 27.5 mm long (4 required)
  • Sn3½, Outer Shafts: 0.8 mm wire, 35 mm long (4 required)
  • Sn3½, Inner Shafts: 0.8 mm wire, 37.5 mm long (4 required)

The transverse shafts are shown in red on the diagram above.  Suggested sizes are as follows:

  • HO: 0.4 mm wire, 12.75 mm long (4 required)
  • Sn3½: 0.5 mm wire, 16.5 mm long (4 required)

Before installing the various shafts, clean out the holes in 3D-printed material with a pin vice and drill bit fractionally larger than the wire size, e.g. 0.05 - 0.1 mm larger.  Drill carefully to avoid breaking any of the parts from the model.  For the longitudinal shafts, another option for cleaning out the holes is to cut a spare piece of wire, say about 100 mm long, at an angle with sidecutters, so as to leave a slightly ragged edge.  By holding this wire in a pin vice, it can be used as a crude drill to ream the three holes for each shaft.

Secure all the wire pieces in position with superglue.

Brake Rods


The are five brake rods to be formed from brass wire.  Suggested sizes are as follows:

HO Scale:
  • Rod A - 0.4 mm wire, 24 mm long, bent 90° one end
  • Rod B - 0.4 mm wire, 19.5 mm long, bent 90° one end
  • Rod C - 0.4 mm wire, 11.75 mm long, bent 90° both ends *
  • Rod D - 0.4 mm wire, 6.4 mm long, bent 90° one end
  • Rod E - 0.4 mm wire, 36.5 mm long, bent 90° one end
S Scale:
  • Rod A - 0.4 mm wire, 32.5 mm long, bent 90° one end
  • Rod B - 0.4 mm wire, 26.5 mm long, bent 90° one end
  • Rod C - 0.4 mm wire, 20 mm long, bent 90° both ends *
  • Rod D - 0.4 mm wire, 9 mm long, bent 90° one end
  • Rod E - 0.4 mm wire, 50 mm long, bent 90° one end
* Fixing hole for "chain" end of Rod C is marked by a dimple on the underside - drill through from underneath.

Secure all the wire pieces in position with superglue.

Brake Rods - Top View (Hopper hidden for clarity)

Vertical Handrails


Each of the vertical posts at the corners of the hopper has a vertical handrail, which can be formed from 0.4 mm brass wire.  The distance between the hole centres is 10.5 mm for HO, and 14.25 mm for S scale.

Corner Handrails


Small starter holes have been provided to locate the handrails near the handbrake at each end of the wagon..  The handrails can be formed from 0.4 mm brass wire.  The holes should be drilled out, e.g. with a 0.45 mm drill bit.

Viewed from above, the corner handrails are L-shaped, the longer leg of the "L" being parallel to the side of the wagon.

For HO, the horizontal legs of the "L" are 3 mm and 2.5 mm long.  The vertical legs of the handrail should be 5.5 mm long, including an allowance of  0.5 mm to be glued into the fixing holes.

For S scale, the horizontal legs of the "L" are 4.5 mm and 3.5 mm long.  The vertical legs of the handrail should be 7.5 mm long, including an allowance of  0.5 mm to be glued into the fixing holes.

Ratchet Handbrake Lever


A short length of 0.4 mm brass wire can be used to simulate the lever of the ratchet handbrake on each end of the wagon.  The length of the wire should be approx. 5.5 mm in HO and 7.5 mm in S scale.Glue the wire into the vertical groove in the handbrake assembly.  The bottom of the wire should be level with the bottom of the groove, with the remainder of the wire projecting upwards.

Uncoupling Levers


A spiggot with a vertical fixing hole has been provided underneath the wagon, next to the coupler, as well as a notched bracket towards the left side of the wagon, when view from the end.  The uncoupling lever can be shaped from 0.4 mm brass wire, with a 90 degree bend for attachment into the central fixing hole.   The diagrams below show the approximate shape to aim for, but feel free to adjust the measurements to suit your model.

After positioning the uncoupling levers, check that the coupler can swing freely and is not obstructed.  After fixing the uncoupling levers in place, it should still be possible to remove the coupler and draught gear box, e.g. for painting the wagon, by sliding it out towards the end of the wagon.

S Scale - Approximate Measurements
HO Scale - Approximate Measurements




Air Brake Hoses


Small brackets are provided next to the couplers on each end of the wagon for air brake hoses.  Cast plastic hoses in HO scale are available from Detail Associates, part number 6206.  In lieu of equivalent hose in S scale, the HO ones could be used also.  Carefully drill out the starter hole provided in the supporting bracket to suit the diameter of the "pipe" on the air hose.  A suggested drill size is 0.65 mm.


Cross Braces

The top of the hopper had small notches on the inside to accommodate 7 cross braces cut from 0.75 x 1 mm styrene strip.  The HO, the length should be 31 mm and, for S scale, 42 mm.  The braces should be pushed to the bottom of the notches so that the top of the braces is slightly below the top of the sides, as indicated by prototype photos.

Photo from Weston Langford collection showing cross braces.

Weighting


If required, additional weight can be added by gluing lead shot or small pieces of sheet lead in the gap between the two sets of hopper doors, and/or 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.  

Monday, 19 June 2017

DB Loco Mechanism Options

As an aid to deciding which mechanism to use for Marbelup Models DB Locomotive, the following summarises the main features of the Hollywood Foundry (HF) and ViTrains (VT) mechanisms.

Comparison of ViTrains bogie (left) and Hollywood Foundry bogie (right)

Bogie Wheelbase


Prototype: 3810 mm = 59.5 mm in S scale
HF Bogie: 59.5 mm
VT Bogie: 58 mm

Wheel Diameter


Prototype: 1016 mm = 15.875 mm in S scale
HF Bogie: 15.7 mm
VT Bogie: 14.8 mm Note: Upper part of wheels is largely hidden by bogie sideframes

Flange Depth


HF Bogie: 0.65 mm (RP25)
VT Bogie: 1 mm - operates on Code 70 or larger rail

Cost (for drive bogies and motor):


HF Single Bogie Drive: Approx. $200
HF Double Bogie Drive: Approx. $250
VT Drive: $140

HF Mechanism Features


  • Choice of 6-wheel (single bogie) or 12-wheel (dual bogie) drive
  • For single bogie drive, cab area is clear to allow for interior detailing
  • Worm gear on each driven axle, with dual belt drive from bogie input shaft

VT Mechanism Features


  • 8-wheel drive (centre axles are idlers and lightly sprung)
  • Twin flywheels included
  • Smoother operation
  • Quieter operation
  • Cab area is clear to allow for interior detailing
  • Worm gear on each bogie with spur gearing to powered axles
Back to Marbelup Models Home Page

Sunday, 4 June 2017

DB Loco Hollywood Foundry Underframe Assembly Tips

Hollywood Foundry Drive Components


It is up to the modeller's individual preference whether to fit two drive bogies or a single drive bogie plus a dummy bogie.

Drive bogie specifications: G16.5/B29.8+29.8/W15.7-110/22:1DUALBELT/NOBOL
Dummy bogie specifications: G16.5/B29.8+29.8/W15.7-110/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 should purchase the wheels, 15.7 mm diameter, from Northyard in New Zealand and send them to Hollywood Foundry in conjunction with each order.  Marbelup Models has a limited quantity of Northyard wheels available for purchase for $35 per set of 12 wheels.



Contact Northyard direct via email: northyard@xtra.co.nz for a quote for the wheels.  The current (September 2016) catalogue price is NZ$1.95 per wheel (not including postage).

Each loco requires 12 x 401N wheels, as illustrated in the following extract from the Northyard Catalogue:



The current (February 2016) pricing for the required Hollywood Foundry parts is:

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

Dummy bogie - $52.80 (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

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.

Total price for two drive bogie configuration is $218.14 (plus approx $10 postage)
Total price for single drive bogie configuration is $171.94 (plus approx $10 postage)

Please not that the above prices set by Hollywood Foundry and are subject to change.

As of late 2016, Mashima Motors are no longer in production.  Marbelup Models has designed the chassis to accommodate other motors including Canon, which are available from some hobby shops in the same size as the Mashima M1833D.  Marbelup Models also has limited stock of another alternate motor which will fit in the space available.


Bogie Pivot Assembly (Hollywood Foundry)


Note:  Prior to assembling the Hollywood Foundry bogies to the underframe, place each bogie on a flat surface (glass is ideal) and check that the bogie doesn't rock from end to end.  Some bogies have been found to have the centre axle set a fraction of a millimetre too low, which means the outer axles don't properly contact the rails and could cause derailments.  If you are unlucky enough to experience this problem, contact Hollywood Foundry for repair or replacement under their Lifetime Warranty.

The underframe is designed for a nominal thickness of washers/packing of 1 mm between the top of the bogies and the mounting surface on the underframe.

The Hollywood Foundry bogies are supplied with two plastic shouldered washers, a formed phosphor bronze spring, a flat steel washer and an M1.4 machine screw. 

For assembly to the 3D-printed underframe, it is recommended to discard the flat steel washer and upper plastic shouldered washer.  This should result in the correct loco height from the rails and the phosphor bronze springs (at both ends) should minimise side-to-side rocking of the loco while allowing some movement to cope with uneven track.

Secure the bogie with the M1.4 screw provided, but don't tighten it fully so as to allow some for and aft rocking movement of the bogie as well.

To check the loco height, fit the underframe and body together, with couplers attached, and check the coupler height against a Kadee HO coupler height gauge.  Be aware that the 3D-printed underframe is somewhat flexible on its own, and relies on the rigidity of the body to keep it straight and level.  The top surface of the footplate should be 26 mm above rail level.

If the loco sits too low, a spacer should be cut from styrene and added above the phosphor bronze spring (or glued to the bogie pivot on the underframe).  The spacer needs to be large enough, e.g. 8 mm square, so that the phosphor bronze spring is effective in minimise rocking.

If side-to-side rocking is still a problem, Marbelup Models can provide details to fabricate a mounting plate from brass sheet and wire which can be fitted to the top of the rear bogie, to provide a "3-point" suspension.  Marbelup Models has also produced a 3D-printed version of this mounting plate which is printed in high-detailed stainless steel at a cost of approx. $16.

Drive Shaft Assembly (Hollywood Foundry)


Brass rod 1.5 mm diameter is suitable for the drive shaft(s).  The required length is approx xx mm.  Check the exact length required from your model.  Allow some "end play" in the universal joint at the bogie end to accommodate movement of the bogie on curves or uneven track.

Hollywood Foundry have published an instruction sheet on the basic assembly. One end of each shaft requires a "flat" to be ground or filed to accommodate the male end of the plastic universal joint.  Grind or file a flat on the shaft with a minimum length of about 2 mm.  The depth of the flat should be 0.3 mm, so that the measurement over the remaining shaft is 1.2 mm.  Don't force the joint onto the shaft if it is very tight, as it may split later.

Hollywood Foundry can supply silicone tubing (free on request with each order) for the motor end of each drive shaft.  The tubing is sufficiently flexible to fit both the 1.5 mm drive shafts and 2 mm motor shaft.

The drive shaft for the front bogie of a loco with both bogies driven must pass through the "tunnel" in the speaker housing.  One technique is to attach the drive shaft to the motor before installing the motor, then pass the drive shaft through the "tunnel" to engage with the universal joint on the bogie and, finally, fix the motor in position with the short M2 screws provided with the motor.  The rear drive shaft can be attached to the motor last, as there is no "tunnel" to get in the way.

For a loco with one powered bogie, it is suggested to install the powered bogie at the rear to avoid the "tunnel" and leave the cab free for interior detailing, if desired.

DB Loco ViTrains Underframe Assembly Tips


ViTrains Drive Components


Remove the plastic body from the ViTrains Class 47 locomotive by gently easing the body sides out to disengage the lateral grooves on the chassis, as per the instruction sheet supplied with the loco.

Unsolder the wires connecting to the bogies and motor (3 green, 3 black) from the Printed Circuit Board (PCB) on the ViTrains chassis.

Unscrew the 4 black screws and remove the PCB.  

Remove the motor and its rubber mounting block. 

Unclip the bogies by gently pressing on the raised clip which engages in the curved slot in the chassis.  Take care with this step as the clip can break if bent excessively.  

Set aside the two bogies and motor with their wires attached.  All other parts of the loco can be discarded.


Bogie Sideframe Assembly


Unclip the keeper plate/sideframe assembly from the underside of each bogie.  There are clips at each end and on each side between the wheels.

Using a fine-bladed razor saw, or similar, cut off the dummy Class 47 sideframes flush with the insides of the sideframes, as per photo below.  Also cut the smaller attachment points at the ends of the keeper plate.  Discard the dummy Class 47 sideframes.

Cut lines to remove dummy Class 47 sideframes.
Optionally, the parts of the previously-removed "sprue" can be fitted to the underside of the keeper plate to provide a representative profile of the traction motors, when the finished loco is viewed side on at track level.  

At this stage, the central joining piece (highlighed in red, below) can be left intact.  Position the two "traction motors" aligned with the matching notches in the ViTrains bogie.  Orientation is not important.  Carefully, drill two 0.8 mm holes through the holes in the "traction motors" for 1 mm dia. x 3 mm long fixing screws.  After drilling the holes, remove the central joining piece and attach the individual "traction motors".  Don't use screws longer than 3 mm as clearance is needed for the gears.

Adding dummy "Traction Motors" to Keeper Plate
Reassemble the keeper plate to the ViTrains bogie. The orientation of the keeper plate is not important.  It the wheels fell out previously, ensure that the power collection wires are correctly located in the grooves on the inside faces of the wheels.
ViTrains Bogie after Reassembly
Remove the support structure and clean up the 3D-printed bogie sideframes.

Remove the central "sprue" from the bogie sideframes as per the diagram below.  The cut lines are highlighted below  in yellow.  Also cut away the raised section, highlighted in red, where the sprue is attached to the end "traction motor".  Part of the "sprue" is (optionally) reattached later, to represent the traction motors.

Cut lines for 3D-Printed Sideframes
Attach the 3D-printed sideframe to the ViTrains bogie, from below.  First, insert the end of the bogie (closest to the brass shaft coupling) into the dummy "traction motor" recess on the end of the 3D-printed sideframe.  Gently spread the 3D-printed sideframe apart to allow the projections on the ViTrains bogie to engage in the rectangular holes on the inside of the 3D-printed sideframe.

Fitting 3D-Printed Sideframes to ViTrains Bogie
Check that the sideframes are fully engaged with the ViTrains bogie by measuring the distance between the insides of the sideframes.  It should measure 23 mm.  If the measurement is greater, check that the rectangular holes on the inside of the 3D-printed sideframes are free of supports, and remove any burrs from the cut ends of the ViTrains bogie.

Once satisfied with the fit, gently squeeze the sideframes together while drilling two 0.8 mm diameter holes into the ViTrains bogie frame, using the small holes provided in the 3D-printed sideframes as a guide.  Use 1 mm dia. x 3 mm long screws to secure the 3D-printed sideframes in position.

Clip the assembled bogies into the "oval" holes in the underframe.  Again, take care with this step to avoid breaking the clips on the bogies.  The green wires should be on the left side of the loco.

Motor and Drive Shaft Installation


Remove the drive shafts and motor clamp from the separate parts "sprue", and clean up the individual parts.

Position the motor in the recess in the underframe, with the wires towards the rear of the loco, and the motor clamp on top.  Secure motor clamp in place with four 2-56 screws.  After checking that the motor clamp is level, measure the excess length for each screw and trim screws to length, e.g. with a cutting disc in a Dremel or similar motor tool.  The remaining screw length should be about 21 mm.

Before refitting the motor clamp, insert the 3D-printed drive shafts into the mating fittings on the bogies and motor flywheels.

Refit the motor clamp and secure with screws trimmed previously.  

Rotate the flywheels by hand to check the motor rotates smoothly.

Height Above Rail Level

The top of the footplate should be 26 mm above the top of the rails.  If necessary, minor adjustments can be made by adding packing (e.g. thin sheet styrene) between the bogies and underframe.  Note that the underframe on its own is slightly flexible, so checking of the height should be done with the loco body attached.

At the front end of the loco, packing can be inserted on the underside of the U-shaped bracket which rests on the top of the bogie assembly.

At the rear end of the loco, packing, can be inserted in the crescent-shaped cutouts which rest on the short metal rods protruding sideways from the bogie assembly.  Alternatively, the short metal rods can be bent slightly upwards or downwards, taking care that they are the same on both sides so that the loco sits level.

Note that the underframe is designed so that the front bogie can rock slightly from side to side to accommodate minor track irregularities, such as when entering a superelevated curve.  

Wiring

For DC operation, connect the 3 green wires to each other and connect the 3 black wires to each other.  Verify that the loco moves in the correct direction.  The loco should move forward when the left rail is negative and and the right rail is positive - or check the direction against other DC locos.  They should all move in the same direction on the same powered section of track.

For DCC operation, connect the bogie pickup and motor wires to the DCC decoder in accordance with the decoder wiring instructions.  The green pickup wires are equivalent to the red wires (left side) for standard DCC wiring.

Thursday, 18 May 2017

R Class Loco Assembly Tips

Parts List


In addition to the 3D printed parts, the following parts must be obtained separately by the modeller:
  • For pre 2017 Models only - 2 brass I-beams (Special Shapes Part No. B-6-3)
  • Brass wire for handrails, etc. (0.4 mm, 0.6 mm)
  • Brass chain (40 links per inch) if modelling original version with chain "handrails" e.g. North Yard CH40 (2 packs required per loco)
  • 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.
  • 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, 65 mm long (cut to exact length) (Hollywood Foundry)
  • 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)
  • LEDs (red and white) and optic fibre, if operating marker lights desired
  • paint as desired
  • 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 (February 2016) pricing for the required Hollywood Foundry parts is:

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

Dummy bogie - $52.80 (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 and Chains


    As delivered, the R class had round handrail posts with chain between them rather than solid handrails.  This was a feature of the R class and was necessary to allow the doors on the side of the long hood to be opened.

    Later, the chains were replaced with solid handrails but with removable segments to allow the doors to be opened.

    The 3D-printed chassis incorporates slots intended to house 2 mm x 0.25 mm brass strip soldered to the bottom of each handrail post, of which there are 25.  This approximates the prototype bracket arrangement and allows the handrail posts to be positioned right at the edge of the footplate.

    The handrail posts can be made from 0.6 mm brass wire and should be 16.7 mm high.  The brass strip should be soldered to the bottom of each post, with 1.1 mm overlap, and project a maximum of 1.8 mm below the bottom of the handrail post.  A suggested construction method is to leave the brass wire and strip as long lengths, and tape them down to a heat resistant surface with the  required overlap, then solder the joint and trim both to the required length.  The brass strip will probably require filing to remove any rough edges prior to insertion into the slots in the chassis.

    Suitable chain is available from North Yard in New Zealand, part number CH40 (300 mm length).  Two packs are required per loco.  Railwest Models normally stock this chain also.

    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 - Assembly of Brass I-Beams (Pre 2017 Models Only)


    From 2017, the I-Beams are included in the 3D-printed chassis.  The brass I-Beams are not required.

    The underside of the chassis includes two longitudinal slots which are designed to provide a secure attachment for the brass I-beams.  The brass I-beams add some weight and rigidity to the chassis, as well as replicating the appearance of the steel I-beams in the prototype chassis.

    Cut the brass I-beams to a length of 236 mm, or a fraction under.  The I-beams should fit between the inside of the headstocks with a small amount of room at each end so that they do not exert any outward pressure on the headstocks.  Keep the offcuts as they will be useful for checking the fit of the I-beams in the mounting slots.

    At this stage, it is advisable to cut 3 notches in the lower inside flange of each I-beam to facilitate later access to the fixing screws which attach the chassis to the body.  The suggested shape of the notches is highlighted in yellow below.


    The diagram below is a cross-section of the footplate, with the I-beams highlighted in yellow.  The intention is that the I-beams are inserted into the slots, then slid outwards so that the flange on the I-beam engages in the groove to provide a secure attachment.


    Once the support materials have been removed from the underside of the chassis, it will be necessary to do some cleaning up of the I-beam slots.  Firstly, check for any remnants of supports materials on the inside surfaces of the slots and, in particular, in the narrow groove. Cut away any remnants with a sharp hobby knife.

    After filing any burs from the cut end of an offcut of I-beam, test fit it to see whether it will slide into the groove at various locations along the length of the chassis.  Moderate pressure with a screwdriver will probably be required to encourage the I-beam to slide sideways into the groove.  If there are tight spots, don't force it at this stage, as the groove will probably require cleaning out.

    It may be necessary to make a tool from metal strip approx. 6 x 0.5 mm, by bending the first 3 mm from the  end of the strip at right angles.  Insert the bent end of the tool into the groove and slide it along to find and remove any remnants of plastic support material which may be obstructing the groove.  Be careful not to damage the triangular supports under the footplate, the bolster ends or sandboxes.

    Once the groove has been cleaned out so that the offcut of I-beam fits at any point along it, insert the full-length I-beam and gently slide it sideways to engage in the groove.  When satisfied that the I-beam is fully engaged in the groove along its full length and the notches in the lower flange are aligned with the fixing screw locations, it can be glued in position.

    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.