These are 3-jaw pliers that bend track by squeezing it. They can adjust track that is already welded into
place, so that the curve, slope, bank or track spacing can be changed. They can also curve new pieces of
track: a bunch of small squeezes can curve a whole section of track. There are plenty of ways to bend the
track while making it, but once the track is all made it is not too easy to change things. These pliers do the
job. They also make changing the bank of the track easier, where a track curving to the right now also needs
to curve up or down to bank it differently. These pliers have no trouble making compound curves.
They were inspired by the very small version of 3-jaw pliers that orthodontists use. Orthodontists are
experts at bending wire.
Start with a pair of 12 inch pliers. Shorter pliers will be hard to squeeze, and not give the fine control for
subtle bends in heavy track. I cut 1/2 inch off the top jaw, and then welded on a piece of steel. This steel
started as 1/2 inch by 1/2 inch by 1.25 inches long, and then was cut into a curved shape. For welding, I
clamped a big piece of steel below the area of the weld (near the pliers' grips) to soak up much of the heat,
so that I didn't roast the plastic grips on the pliers from the heat transfer down the pliers.
After welding, I ground it to shape, and also ground the opposing jaw to a rounded shape. The faces of the
jaws should be smooth, so that they don't leave marks on the tracks. A screw is tapped into the area of the
grooves to keep the pliers from opening up to a new position, as they no longer need to open any wider than
the first position.
Cross-piece clamping and track spacing jig
This jig holds the cross pieces in position for brazing, soldering or welding to the track. This is my latest version of jig,
having tried other methods before this. It clamps on with 8-32 Allen cap screws. Two screws allow for clamping track,
and small vise-grip pliers clamp the cross piece. The jig will keep the proper track spacing, and allow different angles of
the two pieces of track for curves and banking. Tighten the screws with a 9/64” Allen ball driver, with a
screwdriver-type handle. This tool will reach into and around a lot of tight places, and tighten the screws even when it is
25° out of line with the screw. RBS construction creates lots of tight places. See the drawing (Adobe Reader required)
The jig is made of a piece of square steel bar, 2" long. A shorter piece of bar would clamp the track, but would not be
long enough to grip with fingers for tightening the clamps. I used 3/8" square steel bar here, for track made of 0.102"
stainless steel wire and 5/8" diameter steel balls. (For the Flying Marbellos I had 3/4" track spacing, 15/16" diameter
marbles, 1/8" diameter track wire and a different jig that was harder to make and did not work as well.) The size of the
bar should be chosen carefully for the size track you are making.