|
|
Track-bending Pliers 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) for details. 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. |
A hole is drilled in the center of the bar, and tapped for an 8-32 thread. Use a "gun tap" and you can chuck it in your variable speed drill and run it through in one pass with the drill, as the chips are ejected out ahead of the tap. Two 3/8" long screws will clamp the track. The clamping pieces are each made from a 1/2" long piece of 1/2" x 1/2" steel angle 1/8" thick, with one part cut short and a groove made for the wire. A #16 hole is drilled in the clamping piece: the hole needs to be bigger than the screw to allow for some play in the angle of the piece. Cross hatches are cut in the surface of the bar with an abrasive disk in a Dremel tool. These allow for very secure clamping of the wire, and keep it all from slipping. A piece of 1/8" diameter steel rod is welded or brazed to the end of the bar, to clamp the cross pieces. Small vise-grip pliers clamp the cross piece to the rod, and allow lots of flexibility on how the cross piece is positioned. It is very handy to have about 8 of these jigs. |
Ball is ready to be embedded in plaster. |
The small box is sliced, the big wall holds it together. |
Bounce pad |
Ball Bouncing Pad The ball bouncing off of the pad is one of the most popular features of my RBS's. The most important part of this pad is the slice of a Superball®. If you just try to cut the ball in a saw, if you don't have a way to hold the ball stable then you may get a very bad cut, and also jam or mangle the ball in the blade. I found the solution by embedding the ball in plaster before cutting it on a table saw. A small box just big enough to hold the ball is made out of 1/2" plywood, with one wall of the box a larger piece of plywood. When the box is eventually cut, the bigger wall of the box doesn't get cut all the way through and holds it together until the ball is completely cut. The ball will be cut into 3 pieces: the middle piece to become the pad, and two end pieces that will be discarded. For each section of the ball to be cut, 4 brass nails are pressed into the ball, so that the nails will go into the corners of the box, and not be in the path of the saw blade. The nails are brass, so that if you make a mistake in nail placement, the saw blade will not get harmed. Two nails are also put inside of the box (before the box is assembled) to hold the center piece after it is cut. The ball is put in the box, and the box is then filled with plaster. I used dental stone for the plaster, and Fix-All would work well, too. Use wax paper as a temporary bottom for the box until the plaster sets. Let the plaster harden and dry overnight. Then the ball can be cut on the table saw, leaving a nice disk that is ready to use. The pad is mounted to a disk made of 1/2" thick steel. This thick piece of steel is needed to give a solid mass under the pad. A ring is made of plastic to circle the pad and help hold it in place. The the ring and the pad are glued to the steel disk, using epoxy glue after first roughening the top of the steel disk and the bottom of the plastic ring with #60 sandpaper. Put a thin layer of glue on each surface to be glued, place them together and seat them firmly but do not clamp (epoxy does not like the film thickness to be too thin). Bells A great set of bells can be made from hole saws. They are made of the right alloy to make a very nice ringing tone when struck by a ball. (The tiniest ones don't sound quite as good.) Harbor Freight has a set for a low price. The saws are held in place by screws that only hold them loosely. My rack to hold them has bumpers on the left side, so that a ball cannot miss any of the bells on the way down. A drawing shows how they are attached. |
Inside of the base |
pdf Drawing of bounce pad |
Comments? Questions? |