Sunday, June 9, 2024

SP Jawbone Branch (Part 52) - Curved Front for Owenyo#3

In the last post, (SP Jawbone Branch (Part 51) - Cutting and Aligning the Trestle Spur), I was mostly doing evaluations and starting to chop up the roadbed top skin sheet.

This time, I decided to dive into attaching the front fascia strips before building the spline roadbed.  As I was debating doing this or the spline roadbed first...  I decided this is a better starting point as practice for my spline construction technique.  Also the addition of the pair of front curved strips will increase the structural stability of the whole module at this point.

Quick pin added to hold the curved fascia strip at the right end.

In preparation, I cut an angle on the front edge of the right end-plate.  I used a scrap of 1/2" MDF with slots cut at angles in it to form the right end block for the spline roadbed.  I also didn't get a picture of it, but this photo after the fact still shows the clamp holding the spline end block as it dries in place.

Adding pins to the pre-glued left end joint.

I put a couple areas of Elmer's wood glue at the left end and the right end plate.  Clamps were quickly placed and then I drilled some holes and wire finish-nail the strips in place so they couldn't move linearly against the frame.

Marking the second spline strip where it will dove-tail into the Y-shape joint.

After the basic curved strip was in place, I started working out a thinner strip to double the back side of the front curved strip.  The doubler strip was dampened with water and then Gorilla Glue was spread on the strip and placed on the inside of the curved fascia strip.

Preparing to cutoff second strip, which is still lapping past the top of the module.

A few more finish nails were added... and then clamped across to the far side of the roadbed spline.  I later also drilled a pin into the gusset at this corner joint as well.  This makes a total of four pins into this joint.

Time for All the Clamps!


Two pins finalize this joint, then second strip is camped in place.

The right end was finalized with two finish nails to secure the alignment of the front curved fascia.  This shot shows the doubler strip added and clamped behind the front strip.

Towards the left end of the doubled curved strip, with tail of my wedge strip to the left.

As soon as I got the doubler strip roughly in place, and started securing it with the clamp at the right end, I started securing it around the curve with all the clamps I could get my hands on!

Closer view of the Y-joint of the front frame and front fascia strips.

The inner joint blending the doublers together as the curve ends, I added two nails, one at each point where the 1/4" MDF strips touch.  At the top the wedge strip is visible which I'm using to keep the clamp where I want it and keep the force square to the strips.

Forest of clamps to hold the spline strips together while the expanding urethane Gorilla Glue bonds two strips.

The rest of the clamps being attached around the curve.  I placed a bit of MDF scrap and then a bottle of glue to keep the right end-plate from twisting under the force of the two curved strips.


Closeup of the right doubler strip clamped.  I cut the end of the doubler strip at a matching angle against the end plate.

Metal square in place to check cross square of the module.  The clamp is there to hold the shape of the front curve.

Part way through the construction, I notched the curved spline was pushing the right end plate and right wall frame "open".  So I lassoed the window bracket, which is pretty secure, and clamped against the right end plate.  This was somewhat expected, but I'm glad I caught it before everything was too far cured.  The metal square is there to double check the alignment against the right wall.

Roadbed slipped back in place to check distance and alignment to east end of the module.

Thankfully during this time, I had the door open, so I could sight along the right wall frame, and see that it was mostly straight.  I fed in the main track roadbed just to check overall geometry of the whole module.

Extra pins added to gusset and two at the Y-joint to secure the struture.

At this point I unclamped the whole curved fascia frame and wanted to see how the whole structure was in terms of stability and internal tension, seeing that it was actually holding shape.

Cross-Brace


I decided to add a crossbrace at this point to help secure the front curved fascia strips.  I will have to work the main track spline roadbed around this strip.  The foam scenery material will also need to be added above the bracing and around the up-coming spline roadbeds.

Front joint of new diagonal brace.

I installed a diagonal cross-brace between the front frame right corner to the middle of the front curved fascia frame.  Gorilla Glue was used to both the front and rear joint.  I also drilled out two pin holes and installed wire finish nails to keep the front secure.

Rear glued joint of diagonal brace, held vertically by the clamp.

The rear joint was just supported vertically with the clamp to keep the bottom edge even with the right wall frame beam.

Another forest of clamps to keep all frame member straight while diagonal brace dries.

I ended up placing a large clamp diagonally off the corner of the front square frame to the diagonal brace, with a slight compression, just to keep it straight.  I noticed that the right end-plate was not sitting square with the rest of the frame, because of the spring action of the doubled front curved fascia sheets.  So I also added a large clamp from the window bracket to the end plate, this squeezed the frame structure.

The shape of the module is really coming together now.

After finishing up the structure, the vertical keeper clamp on the rear corner of the diagonal brace was easy to pop loose from slightly over flowed Gorilla Glue.  The diagonal brace is starting to add some good racking and twisting prevention to the module's structure by dividing it into triangles.  The top edge is even with the cut down front frame, where the Trestle Spur roadbed will be placed.

Rough CAD plan for the future foam scenery and showing roughly the same alignment as the photo above.

I'll probably have to shim up the spur roadbed as the fine tuning of the vertical positioning of the trestle will be worked out against the main track curve roadbed, but I'll work that out later.

In Closing


Overview of the module at the end of mounting the front curve fascia strips.

For now that wraps up the construction blog.  I'm expecting the next major step will be cutting a bunch of strips for the roadbed spline, then bob them down to length, and start making modifications to cut notches for the spline to fit into the main framework.


SP Jawbone Branch (Part 51) - Cutting and Aligning the Trestle Spur
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SP Jawbone Branch (Part 51) - Cutting and Aligning the Trestle Spur

In the last post, (SP Jawbone Branch (Part 50) - Fans, Surform Tool, & House Keeping) I was mostly doing a bit of house keeping and setting up the shop with a few minor improvements on the fans to work in the summer time.  Thankfully, it's not yet surface-of-the-sun levels of heat, which will come in August and September.

So here's the starting point for the next round of work on the Owenyo #3 Module.  I'm getting behind in posting these... I actually already have construction up to Part 52, but here's the huge pile of photos and thoughts from the steps leading up to where I'm at now!

I'm looking at changing the alignment of the trestle spur, plus shortening the "west" end of the module.

In these pictures I'm really looking at the alignment of the trestle spur.  Not liking what I'm seeing with the alignment of the trestle and the room... It's time to start cutting!

Bye Bye Spur?!


Well, yes and no.  I used the saber-saw at this point to section the top skin so that I can work with each piece in relation to the trestle and the room.

The top sheet for the Spur is cut off and allows me to play with the alignment.

As I mentioned in the last post, I want to be able to see the south or "west" end of the trestle more and not have it pointed as much at the wall.  I'm pulling the spur roadbed around in relationship to the main line curve.  

Playing with the location of the trestle, curve and how many cars will fit.

At this point I've cut the spur loose and shortened the top skin to be the same length as the shortened frame that I modified last time.  In this alignment, I'm working out enough space on the spur for 4 GS gondolas under the dumping section of the trestle, and enough space for 4 GS gondolas to be off-spotted between the non-dumping end section of the trestle and the fouling point of the spur and main track.

This would work out as the shortened 4-car trestle position.

It's about this point that I start to get greedy with the layout design... Can I squeeze in another GS gondola to get the prototypical 5-car loading, and still have the approach ramp look half-way decent?

Now that the spur is cut loose, I can change position and alignment of the curve.

After a little more re-arranging of the spur roadbed, I've got 4-5 cars under the trestle, and four offspots, which I think is now a little short for the off-spots for the prototype, but I'm leaning towards having the full 5 spots under the trestle, so I don't have to do any selective compression to it. 

As can be seen in the foreground, I've also roughed out a piece of Code 55 flex track for 48" radius main line curve, but as I'll be upgrading the main track to Code 70, this piece of flex track will be used over on the Little Lake Siding, as I want to keep the minimum curves there to 48" radius.

SPNG 9 on Owenyo Transfer Trestle - owensvalleyhistory,com slim rails20_sml

The issue with compressing the trestle is that on my layout, most of the viewing, as trains come into Owenyo or out, or are switching, will present a near dead-on side view of the trestle to them, which will show the compression.

Owenyo Dump Trestle from SW corner and SG side. - Richard C Datin Jr photo

I think the alignments I can get the trestle to now, should be able to show the same angle as the Datin photo above.  The closer bent leg is aligned between the 2nd and 3rd set of rear bent legs.  When I put my eye down near the track and the end of the Owenyo #3 Module, where the side of the narrow door spanning module will be, I can get about the same angle, which will be a good point to shoot for as a first impression as anyone enters the room.

My rough code 55 flex track trestle track is a little short for this exact combination.

The problem of course, is that the trestle should be about 7.5 feet long in HO, and it will hit the wall, so the only question is how much of the transition ramp section (prototypically about 250 feet) can I model before it has to become an image on the backdrop... or maybe, I could "bend" it to become a compressed flat along the wall, but also in a perspective compressed form, as I can't have more than about 12-15" of ramp along the backdrop before it starts hitting the stock transfer platform. - Maybe... I'll have to play with how I could make a slightly 3d flattened perspective version of the ramp parts...

More Pictures of the Trestle & GS Gondolas


Full spur with 8 GS Gondolas, the outer 4 being off-spotted.

I'm mostly coming to terms with the trestle only being 4 cars long, and the the off-spot space matching at 4 cars, which I think will make work for my operation plans.  The foreground spur roadbed is actually climbing too steep, as I have it layed on top of the 1/4" main track roadbed sheet.

Zoomed in low-angle photo of the NG loading trestle.

I may still decide to raise the trestle spur a bit more.  I believe the natural ground level should be about the height of the car's floor, or about 48" above the railheads of the spur.  

High angle view of the trestle spur position.

Here's the space at the end of the spur looks like.  I might be able to fit in another GS gondola, but that will really squeeze the transition and grade sections of the trestle against the wall.

Not really accurate position for the trestle, but if it was one more bent to the left.

This sorta shows the amount of space I have at the end of the trestle, where it transitions to the ramp sections.  

New "Door Bracket"


Additional Bracket above the light switch next to the door.

The cantilevered west end of the Owenyo #3 module is a bit of a problem, as that it wants to twist without any support.  I decided to put together a temporary bracket to support the end beam of the module.  The main problem with this bracket being kept is the arm is too long, because I used one of the extra full-length bracket arms from the rest of the Owenyo-Mojave support brackets.  The other issue is that the screws on this small plate don't actually catch a main frame in the wall.  So I'll be looking to replace this support after I get the structure of the module finished up.

Roughing Front Curve Frame


The west end of Owenyo #3 Module

In these photos, I'm roughing out the front fascia strip.  The main challenge right now is cutting more strips of material to make the main track spline.

This shot shows the permanent wall bracket just past the window, with the front fascia frame strip in place.

The vertical position of the curved front strip falls across the "window bracket".  I roughed out the offset from the main track centerline is set for about 5", which is not maintaining a constant from the track.  This should allow a little more foreground when I'm taking photos of the layout later, but it will also keep the layout across the doorway to a minimum width.

Clamping the weakened front frame joint

Sadly because I've not put in the rest of the cross bracing to support the front frame and keeping it's spacing correct and square yet, the front left corner joint cracked, so in these shots I'm re-gluing the joint, and holding it square against the spline roadbed base that I built during the last post.

A closer view of the wedge shaped curve joint between the front frame and the curved fascia frame.

The front fascia frame will be clamped for the first 2-2.5" past the joint and then I'll fill the wedge-shaped joint with glue in the future, but it's a good thing to check at this point in the build.

Track Supports & Grade Checking


I ran the grade calculations for a 1.25% grade, which is 1.25" rise in 100" run, 0.625" in 50", or 0.375" in 25".  Unfortunately, my bubble level is only 28" long, which will mean I need a 0.0375" riser block.  The only scraps I have handy right now are some 1/4" scraps.  So that means I need to divide the 25" run into 2/3s, or 16.66".  This length is about right to nicely slide along the top-skin roadbed and check the grade.  

Temporary track support where the main track roadbed crosses the front frame member.

One problem is that the front frame piece is sagging just slightly.  So I'll probably not be setting the grade without getting some more structure under there to support it first.  I'll have to work this out before I finalize exactly how deep the notch will be made for the main track spline to fit over the front frame beam.

This shot shows the permanent wall bracket just past the window, with the front fascia frame strip in place.

For now I'm using a scrap piece of 1/2" MDF strip for the main track riser at the window bracket.  This will be mostly replaced with the under roadbed spline, but I'll probably add a rib here to support the rear and forward curved fascia frames to keep the module square and stable.

Cheating to Part 52...


Showing underside of bubble level with 1/4" shim.

These are just a few shots from Part 52 timeframe, showing how I am using my bubble-level with 1/4" shim block 16.66" down the length, which works out to 1.25% grade.  I cheated and made a few pencil and Sharpie marks to easily be able to align the shim with the level.

Mid-curve grade check.

The risers seem about right, matching the CAD model in my computer.  All of this is rather guestimates, because the 1/4" MDF roadbed top skin is pretty flexible.  Even the weight of the bubble level sitting between risers will change the grade and level readings.

Bubble level through the vertical curve transition section.

The final grade will be set by the upcoming spline roadbed, with the vertical curve easement baked in, then the top skin applied over the top.

In Closing


I played a bit more with the Trestle Spur.

That will do it for now... I want to keep this post slightly less than an epic saga.  I'll be posting Part 52 shortly with more progress.  

Jason Hill

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Thursday, June 6, 2024

SP Jawbone Branch (Part 50) - Fans, Surform Tool, & House Keeping

This is a quick update post as far as my Jawbone Branch building blog go.  I find it amazing that this is already the 50th post in the SP Jawbone Branch Layout series of blog posts.  The layout's been under construction now for about 3.5 years, starting in early 2021.

House keeping time on the Jawbone Branch this week with the new twin "window" fan

In the last couple posts I've been mostly working on construction of the new corner in SP Jawbone Branch (Part 49) - Spline Start for Owenyo 3rd Module Construction.  I want to just do this as a combined summery of what I've been doing around the shop on the branch this week.

Leveling the Trestle Spur


In the last post, I notched the front frame of the Owenyo #3 Module for the main track spline and the bottom of the Trestle Spur's roadbed.  I put a series of blocks to shim the roadbed over the staging yard to bring the roadbed level.

I decided to do a quick double check the level of the Trestle Spur on the Owenyo #3 Module.

All's good here, the trestle spur's roadbed is nice and level.  Then I extended a mark from the roadbed over to the back frame, so when I connect the supports for this section of roadbed it should remain level.  I'll probably put in some MDF ribs under the roadbed like I did before on the other Owenyo modules.

As I finalize the spur's alignment, I'll be cutting off the extra curve at the right end of the module, and I plan once the spline is finalized and the rest of the framework is done, I'll then start putting in the bracing to support the spur.

Let There Be Fans!


A year or two back, when I was working regularly out in the shop during the summers, I put this fan up in the window next to the end of the Owenyo scene.  I don't think they had semi-subterranean wind turbines buried in the desert at Owenyo!... 

For several years I've used this large box fan to cool off the shop.

Sadly the original fan didn't fit very well with the modules, let alone the future curved section of main line which will need to cross in front of it coming out of the Mojave Staging yard under Owenyo.  The problem with using this large box fan in the window is that it's too large, plus the Owenyo #1 Module wasn't designed to accept the fan.  I was looking at cutting a notch in the corner of the module, but that would also compromise some of the structural integrity of the module... but I'd really prefer a better fan for the location...

Time for a New Fan!


So this last week I went on the hunt for a twin window fan.  I ended up finding one at one of the local box-stores which was only about $30!  

Twin "Window" Fan, which fits nicely in the 23" x 12" open window.

I put it in the other night and it fit nicely once I notched the corner bracket supporting the end of Owenyo #1 Module with the saber-saw.  This one is interesting in that it has two regular fan settings, plus a "night" setting, which is a lower power setting, which keeps the sound down, but still keeps the fans moving some air.

A minor note on this fan, and maybe the series production of them, they put the labeling for the Fresh Air and Exhaust Air sides of the fan on backwards.  After checking the air flow, I went ahead and changed the labels with my Sharpie pen.  The nice thing is that the fan's exterior is symmetrical, so if I want the air flow to draw and push the other direction, I can simply flip which side is towards the window.

In-Backdrop Ducting?


For only $30, I might snag another one and mount it in the other window under Owenyo #3 Module... however that will require a little rework of the corner bracket which is a little too close to the corner and overhangs the window.

Curved Backdrop which will cover the upper parts of the window.

I'm considering putting a fan duct into the corner, behind the backdrop corner radius of the Owenyo #3 Module.  This duct would have to do a bit of an S-curve to get around the staging yard and then a manifold to align with the far fan of the future twin fan, which I plan to put in the window.

If I set up the in and out sides of the fan properly (which this fan had labeled backwards!), I think this would be a great way to have the fan pull the hot air from the top of the room, down and out the window, which does get annoying during the hot Nevada summers.

Surform Tool


Surform tools are a great little took which is a cross between a cheese-grader, a rasp, and bent into a slight curve.

I grabbed a new tool so I can work on the foam scenery.  It took some hunting to multiple stores, who's staff didn't know what I was talking about.  Thankfully the local ACE Hardware had a helpful young guy who knew their stock, and once he realized what this was called, he knew exactly where it was!

A properly debris-covered Surform tool...

I ended up turning the blade section around so it is a "pull" tool now.  It required a little bit of minor persuasion with a pair of pliers on the wrap around tabs to remove the blade.

Plan for the foam to make a mess with the Surform tool.

I put a plastic storage bin lid on the lower Mojave Staging roadbed to catch most of the flying and floating foam bits that the Surform tool launched while I was adjusting the shape of the foam scenery.

How Owenyo #2 once the foam was carved down to the MDF frame edge shape boards.

It worked pretty well to have the MDF pre-cut to the cross section land-form that I wanted the foam be taken down to.  I will have to come back later and either sand down the corner of the MDF edge or build up the scenery form with Sculpt-a-mold when I get into doing the top scenery, which I'm not ready to do yet.  I plan to do that after I get all the track work in, wired and tested.

In Closing


And the part that sucks about all projects... Vacuuming up afterwords!

Curved Backdrop which will cover the upper parts of the window.

As I said at the top, house keeping time... I had to break out the shop vacuum and clean up all the loose MDF dust from cutting Owenyo #3 Module and now all the scenery foam that was kicked up by breaking in the Surform tool.

Next time, I'll be getting back to working on Owenyo #3 Module's roadbed skin and spline framework.

Jason Hill


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