Tuesday, 13 October 2015

WBC Guards Van Construction Tips

The WBC guards van is printed in two sections, representing approx one-third and two-thirds of the van.

Removing Support Structures


Carefully remove the support structure from both parts of the guard's van.  It is suggested to use a sharp knife to carefully cut the supports away from the roof, ends, and the underframe.  Take particular care around the steps, gas cylinders and the brake gear underneath the floor.

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 gear.  An Exacto type hobby knife with a sharp pointed blade (Exacto #11 or similar) is quite useful for getting into the nooks and crannies.

Additional "guards" have been printed, as shown below, to protect the side and end steps during production and shipping.  Once all supports have been removed around the steps, these guards can be cut away from the floor of the van.  Altnernatively, you may wish to leave these guards in place until most of the other work on the van has been completed.  Note that there is also a guard behind the dividing bar on the large, rectangular window.



Go over the model and smooth off any remnants of the fine supports which will be visible after assembly.

When finished, test fit the two halves together but do not glue them together until the glazing has been prepared.

Window Glazing


Each side of the WBC has guides adjacent to the windows to secure glazing material and slots in the floor which allow the glazing to be inserted after the model is painted.

However, the glazing must be prepared and test-fitted before the two halves of the body are glued together.  Each piece of glazing is identified by means of lettering on the underside of floor L1-L5, R1-R5.

WBC Glazing Right Side (Left Side is the same)
The glazing material (i.e. 0.25 mm clear styrene) should be cut into strips approx 50 mm long and test fitted into slots and guides.  The widths of the strips are as follows:

R1, R5, L1, L5: 9.75 mm (4 required)

R2, R3, L2, L3: 8.25 mm (4 required)

R4, L4: 12.75 mm (2 required)

Ensure that the slots in the floor for each piece of glazing are free of obstructions, e.g. supports from the 3D printing process.  If necessary, clear the slots using a very fine knife blade until the glazing strips can be inserted from below the floor.

Test fit the glazing strips into the guides either side of the windows.  If necessary, clear out the grooves in the guide using a very fine knife.  Another possible technique is to use a scrap piece of 0.25 mm brass as a tool by inserting it into the slots in the floor.

Once satisfied with the fit of each glazing strip, mark each strip where it won't be visible later with the appropriate position code, i.e. L1-L5, R1-R5 and set it aside.  The strips can be trimmed to length now or later, at the time of final installation.

Body Assembly 

Once the window glazing has been prepared and marked for later installation, the two body sections can be glued together, e.g. with superglue.  Some filling and sanding will be required at the join, particularly on the roof.  The join on the ends is disguised by the vertical ribs.  Tamiya plastic putty works well as a filling material.

When filling and sanding the roof, be careful not to damage the raised ventilator on the roof.  If damaged, a "spare" has been printed within the centre sill on the underframe which can be installed in place of the damaged one.

Fixing Holes


The fixing holes for the couplers and bogies are intended for 2-56 (or 8BA) screws.  The holes  should accept screws without tapping.  If the screws seem particularly tight, drill through with a 1.8 mm drill bit.

Bogies


The Marbelup Models WBC 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.


The bolster section of each bogie half contains two holes intended for 1.5 x 6 mm self-tapping 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 1.5 mm drill.  The smaller hole, nearest the bogie sideframe, should cleaned out with a 1.2 mm drill.  Carefully drive a self-tapping screw into each of the 1.2 mm holes to form the thread.  If it feels tight, back the screw out a bit before continuing.

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 bogies are designed for 10.5 mm disc wheels with 25 mm axles.  Suitable wheels are available from various suppliers, including Steam Era Models (Part No. WH5).  SEM retailers include End of the Line Hobbies in Victor Harbour, SA, Casula Hobbies in Sydney and Train World in Melbourne.

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 WBC is designed for Kadee "whisker" couplers.  Either the #158 (scale size) or #148 (normal size) couplers can be used, with #262 draft gear boxes.  Because the #262 draft gear boxes are a bit hard to obtain, Marbelup Models now supplies these free of charge with each model that requires them.

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

Handrails


Small starter holes have been provided to locate the various handrails, which can be formed from 0.4 mm brass wire.  The starter holes will need to be drilled out, e.g. with a 0.45 mm drill bit in a pin vice.
Handrail Locations
The approx. dimensions for bending each handrail are as follows:

End Handrails: 10.5 mm between hole centres.  4 required each end.

Door Handrails: 16 mm between hole centres.  4 required each side.  Note that these holes are at an angle of approx. 45 degrees, when view from the top of the van.

Door Handles: 1.75 mm between hole centres.  2 required each side.

Roof Handrails: 5 mm between hole centres.  4 required.

Handrails should be fixed in place with superglue.


Brake Rods


There are 5 brake rods which should also be formed from 0.4 mm wire, and the starter holes drilled out with a 0.45 mm drill bit.

Brake Rod Locations
Approx lengths are as follows:

Long brake rod: 33 mm not including right angle bend (approx. 1 mm) at one end.

Medium brake rod: 22 mm not including right angle bend (approx. 1 mm) at one end.

Handbrake rod (near gas cylinders): 10.8 mm not including right angle bends (approx. 1 mm) at both ends.

Brake Lever Rods (near brake cylinder): 11.7 mm and 12.4 mm not including right angle bends (approx. 1 mm) at both ends.

Air Brake Hoses


Small starter holes are provided next to the couplers on each end of the van for air brake hoses.  Cast plastic hoses are available from Detail Associates, part number 6206.  Carefully drill out the starter holes to suit the diameter of the "pipe" on the air hose.  A suggested drill size is 0.65 mm.

Uncoupling Levers


A spiggot with a vertical fixing hole has been provided underneath the van, next to the coupler, as well as a notched bracket towards the left side of the van, 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 diagram below shows 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, by sliding it out towards the end of the van.

Weighting


If required, additional weight can be added by gluing lead shot or sheet lead between the various frame members of the underframe, where it would not be seen in normal operation.  Weight can also be fixed inside the van prior to assembling the two parts, but it should be securely fixed in place (e.g. screwed) to ensure it doesn't come loose.

Painting


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

Thursday, 1 October 2015

Clerestory Roof Z Van Construction Tips

The clerestory roof Z van is printed in two sections, representing approx one-third and two-thirds of the van.  Versions are available with end platforms at one or both ends.  These instructions apply to both versions.

At this stage, the Sn3½ and4 mm scale version of the van have been produced.

Removing Support Structures


Carefully remove the support structure from both parts of the guard's van.  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 running boards, brake hoses, handbrake pillars and the brake gear underneath the floor.

Because of the ribbing on the brake hoses, the 3D printer's automatic software has generated many support points, which may 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), to separate the support structure, then carefully trim the remnants from the hose.

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

Additional "guards" have been printed, as shown below, to protect the steps during production and shipping.  Once all supports have been removed around the steps, these guards can be cut away from the floor of the van.



Go over the model and smooth off any remnants of the fine supports, especially on the edge of the roof on the open side of the main body section.  A sanding stick or small file can be useful for this.  Be sure to clean up remnants of supports on the clerestory roof windows on the open side of the larger section, as these will be difficult to get to once the two sections are joined.

When finished, test fit the two halves together.  Interlock the square pins on the larger section with the square holes on the smaller section. The square pins will each have a "bump" from the supports on the end, so carefully trim these away.

It may be necessary to sand the edge of the roof of the smaller section where if fits under the clerestory roof on the larger section.

When satisfied with the fit, glue the two sections together, e.g. with super glue.  (Note:  If intending to add weight inside the van (See below.), do it now before gluing the sections together.) It may be necessary to lightly clamp the ends of the roof while gluing to get a tight fit.  To get a smooth finish at the join, particularly on the roof, some filling and sanding will be required.  Tamiya plastic putty works well for the filling.

Tapping Holes


The mounting holes for the couplers and bogies are intended for 2-56 (or 8BA) screws.  The bogie mounting holes should accept screws without tapping.

Note for 4 mm scale version: Because of the thinness of the floor where the couplers are mounted, the holes should be drilled through with a 1.8 mm drill in a pin vice, and tapped.

Note:  Tapping the holes is preferable to using self-tapping screws which may fracture the material.  Although fairly robust, the material is more brittle than styrene or polyurethane.  

Bogies


Sn3½ version:  Correct bogies are available in kit form from NorthYard in New Zealand - Part No. B1656.  Wheels are included.

4 mm scale version: The VR TT30 bogies from Steam Era Models are a reasonable substitute.  Each bogie fixing on the guards can include two ridges which may need to be ground away to allow the van to sit at the correct height.  The ridges add 0.5 mm to the height.

Couplers


The ZBA 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 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.

Truss Rods


The truss rods can be formed from brass wire.

4 mm Scale Version: From a length of 0.5 or 0.6 mm wire,  64 mm long, form a 18° bend 19 mm in from each end, to leave a horizontal section 26 mm long.

S Scale Version: From a length of 0.8 mm wire, 78 mm long, form a 18° bend 23 mm in from each end, to leave a horizontal section 32 mm long.


The truss rods should fit in the recesses in the bottom of the queen posts and in the grooves provided on the inside of the sideframe members.

Handrails


Small starter holes have been provided to locate the various handrails, which can be formed from 0.4 mm brass wire.  The starter holes will need to be drilled out, e.g. with a 0.45 mm drill bit in a pin vice.

Handrail Locations
The long handrails on each side curve down at the ends, and starter holes have been provided in the corners of the body, which are angled at 45ยบ to the sides and ends.  Turned brass handrail knobs are available in various lengths (e.g. from Markits), to allow for the thickness of the doors (0.8 mm), so that the handrails remain parallel to the sides.  Note that there should be a gap in the handrail on the opening side of the door (closest to the guard's lookout).

The starter holes for the vertical railings at the end go right through the end beams. Take care when drilling these out to keep the hole vertical.  The vertical railings can be inserted from above into the holes in the end beams, then pushed up into the holes in the end of the roof.  If replicating the horizontal rails at the ends, these can be soldered between the vertical railing prior to installation.

4 mm Scale Version:  The horizontal rail should be 12.7 mm above the floor level.  The vertical railings should be 8.5 mm apart (centre to centre).

S Scale Version:  The horizontal rail should be 12.7 mm above the floor level.  The vertical railings should be 8.5 mm apart (centre to centre).

Brake Stands 


The brake stands should have an L-shaped handle, as per the diagram below.  One option is to simply bend a piece of 0.4 mm brass wire and glue it to the top of the brake stand.

A slightly more complex option is to solder a vertical wire to the L-shaped handle, for fixing into the brake stand.  If using this option, the inside of the brake stand is hollow but the upper section would need to be drilled out (0.45 mm) from below to accommodate the vertical wire.

4 mm Scale:  The horizontal part of the handle should be approx. 6.3 mm long and the vertical part approx. 1.8 mm.

S Scale:  The horizontal part of the handle should be approx. 7 mm long and the vertical part approx. 2 mm.



Weighting


If required, additional weight can be added inside the van or, alternatively, by gluing lead shot or sheet lead between the various frame members of the underframe, where it would not be seen in normal operation.  If adding weight inside the van, ensure it is fixed securely (e.g. screwed) so that it can't come loose at a later time, and that the weight is symmetrical about the longitudinal centre line of the van..

For the S scale model, the desired weight is about 95 grams.  (Refer to Sn3½ blog article.)  Using the suggested North Yard bogies, the weight of the van is about 68 grams, so about 27 grams if additional weight is required.

Painting


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