Shoulder Horseshoes


08/21/19 - This is the assembly process, illustrated with Ver 2.0 parts. There will be some small changes when we start delivering Ver 2.1 parts.

This is a 3d model of the CS:R Shoulder - Horseshoe made from the CS:R Shoulder - Horseshoe 20140601.pdf drawing and including the Horseshoe Shim based on JAG's drawing.

The image links to a 3d pdf file, click on it if you want to be able to rotate the image around and examine it from other angles. (Note, the 3d.pdf file opens in a new window. If you have problems with the 3d feature you may have to upgrade to the latest version of Adobe Reader).

After 'activating' the 3d mode by clicking on the display
select a part by left clicking on it (the part will be highlighted)
then right clicking brings up a window.  Follow the sequence
-> part options -> part render mode -> transparent
to make the outer parts transparent and the inner
details visible.

This is the Shoulder.Horseshoe.188 panel.
Since the two Horseshoes are mirror image there will be a similar panel (called Shoulder.Horseshoe.mirror.188 - naturally)

The first thing you should do is use a marker to label the parts in the panel by their assembly Layer. The .188 parts will be assembled as pairs - L1 & L2 and L4 & L5 you don't want to mix them up!!! L3 is on the .125 panel.

Label the mirror panel parts L1m, L2m etc. and Only remove one set of parts from their panels at a time to avoid confusing mirror and non-mirror parts.

The .188 parts have a .05 deep edge cut into them so that when they are assembled there is a .1 deep channel between the layers. During assembly make sure you have the correct part surfaces facing each other BEFORE you start gluing them.
This is the Shoulder.Horseshoe.125 panel.
This image will be updated with a V2 image that has 2 sets of parts in the panel.

Because there is no edge on the .125 panel parts they are the same for both the mirror and non-mirror Horseshoes.

This is the Shoulder.Horseshoe.040 panel. This image will be updated with a V2 image that has twice as many parts.

The upper row of parts are the liners for the boxes. The lower row is the skins for the outside edges. there are 2 box bottom parts to make the depth of the boxes closer to the drawing standard.

Assembling the Layers
Begin  with Layers #1 & 2 - make sure the channel is in the center and the cutouts in the parts line up.

I've used spring clips (aka binder clips) - C-clamps might have been a better choice.

Left: Make sure the corners line up. Once the alignment is OK use Weldon #3 cement to join the parts.
The hole above is a glue point - try not to overfill it.
Once the cement on the first 2 layers has set, add layer 3.
This is  what happens when you get sloppy with the cement! It's hard to see, but the red V's point to places where the cement got under the spring clips and caused the plastic to melt. -  If it happens to you be sure to sand down the ridges!
Right: I've added the Nutserts to layer #4 - that part will be supplied with the Nutserts installed unless you ask me to leave them out.
Left: you'll need lots of clamps to hold both the inside and outside layers together.
Above, Left & Below: Alignment of the layers where the points come together is critical because of the visibility. Because of the channels cut into the parts it's not possible to trim them back without reducing the channel depth.
Lining the Boxes
One of the drawbacks to using multiple layers for the construction of the horseshoes is that the layer joints are visible and difficult to cover up during the finishing/painting process. My solution is to glue small pieces of .040 to the inside of the boxes (cutouts) as well as to the outer edge. (image out of date)

there are sets of parts for all 3 of the cutouts. note that for the square cutouts the pieces are two different lengths - two slightly longer than the other two. All of the pieces are oversize in height and will be trimmed down after they are glued in place.
Left: If you haven't glued thin .040 stock now is the time to try with some scrap pieces. Cut some pieces from the scrap.
And see what happens when you apply cement.
Below - The corners of the cutouts are slightly rounded.  Use a file with a 'dead' edge (no teeth - so it only removes material in one direction) to sharpen up the corners After just a little filing!
Left: test fit the pieces. For the sq cutouts start with the longer pieces. Sand the end down (if necessary) until the piece just fits.
Clamp the pieces in place and apply cement. Repeat the process for all of the cutout edges.
I'm using a large coarse file to remove the edges of the box liners that stick up above the edge of the cutouts. When filing hold the file almost flat to the surface so the finished edge is square to the surface.

Not my best work, but this is the bottom of the cutout and won't be visible.

With the Top & Bottom edges of the cutout filed level it's time to attach Layer 5 to the bottom of the Horseshoe.
Above & Right: as with the other layers, alignment is critical! Once you put the cement on it's too late!
Gluing on the Outer Skin
Gently File down any high spots -  be careful not to put a flat spot on the edges. Right -  place thin cardboard spacers on the underside - tape in place.

Start at the bottom edge. Extend the strip over the end.

The spacers enable ~equal edge overlap on both top & bottom.

Clamp Down the other end. Make sure it also extends over the end. Make sure skin is tight on the curved section - Apply cement.
With 20/20 hindsight I should have taken out the bigger clamps and used them on the curve when I glued the top. In any case if there are sections that are not tight clamp & glue again!
Trimming the Edges of the Skin

work very slowly, with the file held almost level, and only pushing against the horseshoe, file down the edge of the skin.
Check the remaining edge with your finger after every few strokes. Work your way around the horseshoe.
Repeat the process for the edge on the reverse side.

Finally, trim the edge on the bottom of the horseshoe.
Assembled Horseshoe - ready for finishing