Re: Assembling Truss Rods

al.kresse <water.kresse@...>

Beautiful . . . . such patience!  I gave up on O-scale being too small to work with . . . ugh!

Al Kresse

On December 11, 2019 at 7:31 AM Bill Welch <fgexbill@...> wrote:

CAUTION: Slotted Screws Visible

I have started rigging the truss rod system for my CB&Q model’s underframe. I use .015-brass wire for the rods so prior to gluing the Queen Posts in place I used a new Single Edge Razor Blade to widen the slots in the Grandt Line parts, carefully cleaving away hair width slivers of styrene on each of the sixteen parts. This took about three hours with frequent checks to make sure the .015-wire would nest in the slot. Next I drilled #77 holes in floor just inside the bolsters so one end of the .015 wire could pass through the floor.

I did the interior pair first, bending a section of wire at about 75° on the end that goes through the floor and putting it through the hole I had drilled. Then I let the wire sit in the Queen Post’s slot. Resting my small Tamiya pliers against the Post I made a slight bend. Inevitably I had to adjust this bend until the wire now rests in both Posts to achieve the exact bend. I had already measured the distance between the Posts with my Mitutoyo Digimatic Caliper and then divided this calculation by two to determine the midpoint. I used this calculation to trim the wire. Then I repeated the process for the other truss rod section.

Over the years I have accumulated a few packets of Grandt Line Brass Turnbuckles, These are very nicely detailed—albeit very small—parts. Because cyanoacrylate or CA is an effective glue in this situation, it is main reason I use brass wire with these parts. After I have made two good truss rods I trim each one just enough to create a small gap so that I can see through the turnbuckle. Once happy with each brass wire section, I filed each end to rough them up and then put them back in place resting on their respective Queen Post. Next I slipped the turnbuckle back on and make sure it is oriented so I can see through it. When I am happy, I apply a tiny drop of CA to the Queen Post/Brass Wire joints and to only one end of the turnbuckle, creating a slip joint. After these three joints have cured, I bent the wire ends locking them in the slightly oversized holes. With three glued joints and three that are not glued, this assembly can withstand a fair amount deflection without anything breaking.

My goal is to align each of the turnbuckles so that I can slip a piece of scale scrap lumber through the turnbuckles, hopefully all eight but if not four on each side. (As I was taking the photos clouds were playing with the Sun changing the light so I included extras showing the turnbuckles in different lighting.)

Bill Welch


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