02-17-2010, 01:42 AM
And finally, here's the jig for making roofwalk corner grab irons. Contruction is maple, glued together as shown. A #79 hole was drilled through the main block at each corner of the upper block, then the corners of the upper block were trimmed off. A length of .015" music wire (slightly larger than the .012" brass wire used for the actual grabs) was layed, in-turn, alongside each edge of the upper block, then holes were drilled for the retainer pins, short lengths of 1/16" music wire, spaced slightly away from the upper block:
The two closely spaced .015" music wire pins atop the fixture (beneath "grab") are for forming the "eye" at the top of the
corner support piece.
Also shown are four lengths of .012" brass wire - these are the total of the approximate lengths needed for each arm of the grab, plus two scale feet on each end to allow for installation. I usually install these grabs by inserting them through the roofwalk and the car's roof, as most of my roofwalks are built-up on the car. For separate, pre-formed roofwalks, these pieces can be shortened accordingly. The four pieces have been bent, using pliers, at their approximate mid-point.
To shape the vertical piece which forms the support at the corner of the grab, use pliers to make a fairly sharp bend near the end of a length of wire (again, it's easier to work with a longer piece of wire, then cut-off each piece after it's formed - the old X-Acto blade works well for this):
Place the partially-formed eye over the pins, as shown:
Next, using pliers, squish it tightly around one of the pins:
Here's the resulting part:
And the same part after trimming slightly with the X-Acto blade - the loop should be open just enough to allow it to slip over a similar-sized wire and not so long that the bent end hangs below the wire over which it will be hung:
Here are the parts loaded onto the jig. Note how the 1/16" retainer pins hold the arms of the grabs in place:
Here's another view, with one of the "eyes" lifted slightly:
Apply a small dab of flux to each joint, then using a "wet" iron, touch each joint for a moment, allowing a small amount of solder to flow into the area - because the wire is so small, it heats in no time, forming a strong bond. Here's a look at the soldered grabs, still in the jig:
After removing the parts from the jig, I toss them in a jar of lacquer thinner to remove any excess flux, then begin the installation process. (that baggage car step is also visible, below)
First, insert the "eye" leg into the pre-drilled hole at the corner of the roofwalk:
After aligning one of the arms with its hole, grasp that spot with pliers and remove the grab from the roofwalk, then bend the wire accordingly. Seen below, in the grip of the tweezers, is a grab bent thusly:
Re-install the grab into the two appropriate holes, then re-align, if necessary, the other arm until it lines-up with its hole:
Again, use the pliers to grasp the grab at the point where it will be bent, then remove it from the roofwalk, make the bend, and re-install the finished grab:
To make the installation permanent, insert a spacer, as shown, then bend-over the wires where they protrude through on the underside of the roofwalk (or inside the car, if installing in that manner). I used a piece of .020" thick styrene strip for this one, but have also used .030" and .040" spacers - some cars look better, in my opinion, with the greater spacing, especially refrigerator cars, where there's often no lateral roofwalk. Remove the spacer after bending, then apply ca, from the underside, to secure the joints:
Here's the finished product, on a yet-to-be-modified boxcar:
Wayne
The two closely spaced .015" music wire pins atop the fixture (beneath "grab") are for forming the "eye" at the top of the
corner support piece.
Also shown are four lengths of .012" brass wire - these are the total of the approximate lengths needed for each arm of the grab, plus two scale feet on each end to allow for installation. I usually install these grabs by inserting them through the roofwalk and the car's roof, as most of my roofwalks are built-up on the car. For separate, pre-formed roofwalks, these pieces can be shortened accordingly. The four pieces have been bent, using pliers, at their approximate mid-point.
To shape the vertical piece which forms the support at the corner of the grab, use pliers to make a fairly sharp bend near the end of a length of wire (again, it's easier to work with a longer piece of wire, then cut-off each piece after it's formed - the old X-Acto blade works well for this):
Place the partially-formed eye over the pins, as shown:
Next, using pliers, squish it tightly around one of the pins:
Here's the resulting part:
And the same part after trimming slightly with the X-Acto blade - the loop should be open just enough to allow it to slip over a similar-sized wire and not so long that the bent end hangs below the wire over which it will be hung:
Here are the parts loaded onto the jig. Note how the 1/16" retainer pins hold the arms of the grabs in place:
Here's another view, with one of the "eyes" lifted slightly:
Apply a small dab of flux to each joint, then using a "wet" iron, touch each joint for a moment, allowing a small amount of solder to flow into the area - because the wire is so small, it heats in no time, forming a strong bond. Here's a look at the soldered grabs, still in the jig:
After removing the parts from the jig, I toss them in a jar of lacquer thinner to remove any excess flux, then begin the installation process. (that baggage car step is also visible, below)
First, insert the "eye" leg into the pre-drilled hole at the corner of the roofwalk:
After aligning one of the arms with its hole, grasp that spot with pliers and remove the grab from the roofwalk, then bend the wire accordingly. Seen below, in the grip of the tweezers, is a grab bent thusly:
Re-install the grab into the two appropriate holes, then re-align, if necessary, the other arm until it lines-up with its hole:
Again, use the pliers to grasp the grab at the point where it will be bent, then remove it from the roofwalk, make the bend, and re-install the finished grab:
To make the installation permanent, insert a spacer, as shown, then bend-over the wires where they protrude through on the underside of the roofwalk (or inside the car, if installing in that manner). I used a piece of .020" thick styrene strip for this one, but have also used .030" and .040" spacers - some cars look better, in my opinion, with the greater spacing, especially refrigerator cars, where there's often no lateral roofwalk. Remove the spacer after bending, then apply ca, from the underside, to secure the joints:
Here's the finished product, on a yet-to-be-modified boxcar:
Wayne