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900 Echols Street SE
Vienna, VA 22180    703-319-0840

High Performance, Affordable Accessories for
Pinewood Derby, Hot Wheels, Soapbox Derby, and other racing formats.

Instructions

Linear Start Mechanism
for BestTrack

Models GLB
GLB-D
GLB-E

Topics

Identifying your Model

The GLB has a single control input on the left. The input on the right is the power socket. The solenoid can be activated by a push button switch, PB1, PB2, or PB3. It can also be activated by the Light Tree, or by the SCI under computer control.

The GLB-D and GLB-E have two control inputs. It is expressly designed for the Light Tree to be plugged into the top input. Then, the bottom input (PB2, PB3, or SCI) will trigger the Light Tree into countdown. When the light gets to green the solenoid is activated.

The suffix -D or -E are minor configuration changes, and are of no significance to the user.


Attach the Control Rod

The brass pull rod is normally shipped with a pair of right angle turns, and is meant to be inserted into a 3/32" hole in your startgate handle. This is best because there is no slop in the action. The location for the hole is 1.25" from the bottom of the handle.

Lately, BestTrack is shipping handles that already have a larger hole drilled in this area. In this case, simply drill the hole nearer to the edge without the notch. Some customers report that they have used this larger hole successfully by using a needle nose pliers to reform the brass rod to have a hook. The brass is Alloy 260, which can be bent thousands of times without fatigue.

Mounting the GLB to the Track

Slide the pair of bolts (included) down the bolt channels on opposite sides of the track's right-most lane. Set the GLB in place and install the nuts loosely, allowing the GLB to move. Position it so that the solenoid plunger bottoms out at the exact point where the handle releases the peg bar. At that point, tighten the nuts. Test again, using your fingernail to bottom out the plunger. When you are satisfied with the action, attach the power supply and trigger cable(s). Enjoy!


Design Goals

In addition to low price and reliability, we selected the smallest solenoid which we determined gets the job done. The goal was to introduce the minimum shock possible into the track during start.

See this video for a good explanation of why small is good.

Improving the Start Gate Performance Margin

The BestTrack was not designed with solenoid operation in mind. The notch in the handle is at least twice as deep as it needs to be, and is not controlled. The edges are sharp and can bite into the peg bar, causing friction. Moreover, the diagonal spring has about ten times the force necessary to keep the peg bar securely in the handle notch. A child has no trouble operating the handle, but a person's arm is much more powerful than a solenoid. While the GLB will work without problem, you can greatly increase the margin of performance by following these steps:

1. Use a less powerful spring for the handle return. The diagonal spring is the same one used to rotate the peg bar. Modify the spring so that it is 3.25" long, rather than the original 2.5". Simply pull the last few turns of the coil beyond their elastic limit. It is a good idea to use a needle nose pliers to secure the modified spring to the gate assembly so that the spring stays with the assembly, and does not get mixed up with the other springs.
2. Reduce the effective notch depth. Remove material below the notch so that the effective notch depth is about 3/16". This gives plenty of security, while eliminating unproductive work that the solenoid must perform. With less work to do, the solenoid performs more smoothly. A belt sander is ideal for removing the bulk of the aluminum. Finish up with a fine file, and polish with steel wool.
3. Eliminate other friction.

Looking directly into the notch, round the bottom edges so that it engages the peg bar only in the center. You can actually carve the aluminum with an X-acto knife. Make this surface as smooth as you can.

Then, the lever's notch will leave no scratches on the peg bar, and the action will be smoother.

Use a little lubricant on the axle bolt and nut. Too loose is as bad as too tight.