Best Of Scratchbuild Project - Van Iron Woodchip Cars

[BCR 570]

Underframes (Part 6)
Next up is a start on the bolsters.  These are worth taking a lot of care and time with as they play an important part in the operation of the car.  I tried to make the bolsters from solid beams of styrene, but was unable to achieve the desired tapers as I could not hold the part steady or file the tapers consistently.  I elected instead to use two cross-members for each bolster and then cover them with a plate on top; if the plate was a little wider than the pair of cross-members then I would be able to represent the flanges along the bolster beams.

If the bolster plates are .156" in width and the cross-members are made from .020" thick styrene, then the two cross-members need to be spaced .100" apart, or .050" on either side of the mark for the centre of the bolster.  I placed my thin square on the bolster centreline, and placed a .050" thick styrene spacing jig against the square:




I installed the outer bolster cross-members first.  I applied glue to the bottom and inside end of the cross-member, and placed it against the jig and the centre sill:




As soon as the cross-member was in place, I held it there with tweezers and used my knife to slide out the spacing jig:




After verifying that the cross-member was accurately placed, I applied more glue with the artist's brush:




I had organized the bolster cross-members into matched pairs, so I placed the second one against the centre sill near its partner so as not to mix them up:




After installing all four outer bolster cross-members, I began installing the inside ones.  This was done by placing a .100" thick styrene spacing jig inside the outer cross-member, and then placing the inside one against the spacing jig:




Again, as soon as the new cross-member is in place, the spacing jig is slid out and away:




A second application of glue is then made to lock the part in place:




Here is the first underframe, now with centre sills, centre cross-members, and cross-members for the bolsters now in place:




And here are the six underframes after reaching the end of this stage:




The remaining cross-members are next.

Tim

[BCR 570]

Underframes (Part 7)
Three updates in as many days - I am on a roll.  With the centre cross-members and those for the bolsters now in place, the remaining cross-members can be added.  After cutting the strips to length and cutting the taper with the jig, they are ready for installation.  To align them so they are perpendicular with the centre sill and spaced evenly between each other, I built a spacing jig comprising a block .260" wide mounted on a .040" base.  I ensured that the block was square to the edge of the base and overhanging so that it would butt up against the centre sill. 

Here is the first underframe, a set of cross-members which have been cut to length and tapered, and the cross-member spacing jig:




The process starts with placing the spacing jig against one of the centre cross-members, and installing the next cross-member on the other side of the jig:




After sliding out the jig, additional glue is applied with an artist's brush.  The glue is applied to the inside of the new cross-member so that the outside is kept free of glue for the return of the spacing jig:




While the glue is drying, I spin the underframe around and install the next cross-member on the other side:




The spacing of the cross-members should match the spacing of the cross-members on the sides of the car.  To ensure this is happening,, I occasionally bring the sides against the underframe to compare the cross-members and side posts:




I continue alternating back and forth between each side of the underframe as I install the cross-members, eventually reaching the halfway point:




The process continues with the second half of the car, except that I am now working towards myself and installing the cross-members against the near side of the jig:




And the second application of glue now goes on the far side of the cross-members, again to keep the spacing jig dry:




Eventually they are all in place and the underframe looks like this:




I am very pleased to reach this stage with all six underframes, which is a major step forward:




The next step will be to infill the centre sill between each cross-member, and install the centre bearing blocks for the bolsters.

Tim

[BCR 570]

Underframes (Part 8 )
With the cross-members now installed on either side of the centre sills, it is now time to complete them by inserting the matching webs between the centre sills.  I have a lot of off-cuts from the cross-members which are .020" x .080" and are already the correct width and thickness.  I fabricated a .080" x .080" alignment jig to fit in between the centre sills, with one end squared off to assist in getting the webs vertical or perpendicular to the centre sills.

Here is the first underframe, the alignment jig, and the stock of off-cuts:




After applying glue, the web is inserted between the centre sills and pushed against the alignment jig which is also sitting between the centre sills:




After removing the alignment jig, I sight across the underframe to ensure that the alignment is indeed vertical:




Once I am happy withe the alignment, I apply additional glue with the artist's rush:




The bolsters also need to be infilled between the centre sills.  These pieces will become the centre bearing blocks, through which I will drill holes for the bolster pins.  These are cut to a length of 3'-0" from .040" x .080" strip styrene:




To assist in locating these in the correct position, I mark the centre with a pencil:




The centre bearing blocks are installed between the centre sills, and centred on the pairs of cross-members for the bolsters:




The centre web sills were installed long to aid in visually aligning them vertically.  After the glue has hardened overnight,they are trimmed short with side cutters:




After trimming all of the centre sill webs, I run a file along the top of the centre sills to ensure that the webs are the same height as the centre sills:




For the centre bearing blocks, it is essential that they are perfectly level for correct operation of the trucks.  For these I run the file flat along the centre sill to achieve a level surface:




With this step complete, I can now install the remaining parts for the bolsters and drill the holes for the bolster pins.


Til next time,

Tim

[DKS]

If it has not been mentioned already, this thread most definitely deserves Best Of status.

[craigolio1]

If it has not been mentioned already, this thread most definitely deserves Best Of status.

2nd

[BCR 570]

Thank you both; we 'll see what transpires.

Underframes (Part 9)
In this instalment I will complete the bolsters, which up until now have comprised two pairs of cross-members with a centre bearing block in between.  To these I will add a centre bearing plate and covers for the bolster beams.  The centre bearing plate is cut to a length of 3'-0" from .020" x .125" strip styrene, and the beam covers are cut long from .020" x .156" strip styrene.

Here is one of the underframes with all of the requisite parts for six underframes cut and ready to install:




This photograph shows a set of parts for one bolster arranged next to an underframe:




The centre bearing plate is glued on top of the centre bearing block.  Care is taken to centre it on the bolster, align it with the outside edges of the centre sills, and verify that it is sitting perfectly level, as this is the surface which will rest on top of the truck:




The bolster beam covers will sit on top of the tapered cross-members, which means that they will meet the centre bearing plate at a slight angle.  To ensure a nice joint, I chamfered the inside ends of the bolster beam covers with a file.  I placed the styrene strips on top of a steel block placed at the edge of my desk and filed the required angle:




The bolster beam cover is then installed on top of the cross-members and slid up against the centre bearing plate:




After everything has dried, I mark the centre point of the centre bearing plates by drawing lines between diagonally opposite corners, resulting in an 'X':




I mark a pre-drill in the centre of the centre bearing plate with a pin, and then drill a hole right through the underframe with a #80 drill bit.  I had previously drilled a hole through the underframe for the bolster pin holes and the hope is that when drilling these holes, the drill bit will find the earlier hole and be guided through the exact location it needs to be.  Achieving a perfectly-centred bolster pin hole is important for optimum performance when the car s are eventually on their trucks:




These holes now need to be enlarged all the way out to a #48 drill bit size for the Micro-Trains bolster pins.  It is important to keep the drill perpendicular to the underframe on both axis during this process so that the hole does not go crooked.  I accomplish this by going up only two drill bit sizes at a time ie. #78, #76, #74, etc.  In this way the new drill bit does not have to work hard to cut through the styrene and it more likely to maintain a straight hole.  After reaching bit size #62, I switch to my larger set of drill bits and a larger pin vise.  (I use the Sterrett A and B vises.)  I rotate trough all six underframes with one drill size, then change bits and repeat the process.  When I get up to #50 size, I then use #49 and finally #48.  This photograph was taken as I worked through the six underframes with the #62 bit:




This close-up shot shows a completed bolster with the centre bearing plate and bolster beam covers in place, and the hole for the bolster pin drilled through.  The centre sill, bolsters and cross-members have all yet to be trimmed:




With all of the bolster pin holes drilled out to #48, a Micro-Trains bolster pin is inserted for a test-fit.  A #48 hole provides a nice tight fit; for a looser fit, a #47 hole also works:




The underframes are now close to completion.  It has been a long process.  In the next instalment I will finish them off with some final trimming and dressing.

Tim

[samusi01]

Another Best Of well-deserved. Thank you for your thorough documentation - inspirational.

[u18b]

Tim,

I see this thread is a few months old.  And I admit I had not followed it (I don't read every thread).

But today the Best Of label caught my eye... and so I now saw what is being done.

I'm very impressed.  Excellent scratchbuilding, but also excellent documentation (written and photographic) of the work.

Well deserved Best Of thread.
Thank you.

[mmagliaro]

Tim,
Superb work! Your model making hallmarks are careful cutting and measuring, use of jigs, and meticulous assembly.  It really shows.  The cars have a crisp, precise look to them.  Everything fits.  Everything is centered and properly aligned.   When these are done, they will look like they came out of an injection mold, except that they will have more accurate proportions and finer detail!

[BCR 570]

Thank you all for your kind comments; good to know that this is of interest to others.  It is less about the cars I am building and more about the methods being used, which hopefully will be useful to others.  I enjoy scratchbuilding, and the best part is that it is relatively inexpensive as styrene is cheap!


Underframes (Part 10)
With their intersecting twin centre sills and tapered cross-members, the underframes have been the most complex and time-consuming part of the build so far.  In this instalment I will cover cleaning up of the parts and preparation for the brake appliances.

The first step in this instalment is to trim the bolster beam covers.  The underframe is placed right side up on the cutting mat and a #17 blade is used to chop off the excess material as close as possible to the edge of the underframe:




A file is then used to dress the side of the underframe at each end of the bolster:




A pair of side-cutters is used to trim all of the cross-members flush with the edges of the underframe:




Again, a file is used to dress the edges of the underframe.  This is followed up with a few swipes of fine grit sandpaper on the True Sander:




The #17 blade is used again, this time to chop and trim the ends of the centre sills:




While the underframes are still flat on the workbench, now is a good time to locate and drill holes for the brake appliances underneath the cars.  After using a pin to locate a pre-drill, I drill the hole with a #80 bit, then work my way up to a #67 bit for the Precision Scale parts:




This photograph illustrates one of the underframes with the brake cylinder and triple valve sitting in their holes.  The AB reservoir does not have a locating pin; it will be suspended from brackets underneath the car at a later date:




And with that, the underframes are finally complete!  It has been a long process but the results are worth the effort, and I learned a lot doing them.  The construction of a test underframe to begin with was a valuable step as it taught me a few things, namely:

- the use of jigs makes for fairly neat and consistent results, and speed up the progress of work of this type
- the centre sills need to be perfectly perpendicular to the floor so that the cross-members butt up against them for a tight fit
- a wider spacing jig is required for the cross-members as they are thinner than the side posts 

Here is one of the completed underframes, all cleaned up and ready for assembly with the ends and sides:




And here at last are all six underframes, also complete and ready for assembly with the the parts:




This is a major milestone in the build as the fabrication work is now largely complete and assembly can finally begin.  This photograph shows a complete set of parts now ready for assembly - from top to bottom are the false floor, steel weight, left side, underframe and ends, and right side:




This type of work generates a lot of styrene off-cuts and bits which now litter my workbench, so I am going to take a little break to clean up.  Then it will be time to start assembling parts; lets hope they all fit together!


All for now,

Tim

[bdennis]

Really cool work. Following along for the ride..

[nickelplate759]

@BCR 570 I keep seeing that nifty N-scale framing square in your photos, and really want a similar tool.  I know that particular one is no longer available (I checked) - anyone know of an easy to find similar tool?   Doesn't HAVE to be marked in N-scale, but that would be nice.  It's the overall size that's most important.

[jpf94]

Spectacular work.  Thank you for sharing.

[Tom Todd]

nickelplate759

You might check Micro Mark.  I found one at: https://www.micromark.com/Mini-Square-3-Inches-x-4-Inches .

Tom Todd

[nickelplate759]

nickelplate759

You might check Micro Mark.  I found one at: https://www.micromark.com/Mini-Square-3-Inches-x-4-Inches .

Tom Todd

That would work - thanks @Tom Todd