Getting the Dimensions of Pinewood Derby Block Right
If you've just cracked open up your official BSA kit, the very first thing you'll possibly notice is the particular specific dimensions of pinewood derby block that a person have to function with. It looks like an easy chunk of wooden, but that rectangular piece of pinus radiata may be the foundation for everything you're regarding to build. Regardless of whether you're a look trying to earn the trophy intended for speed or a parent just expecting the vehicle makes this to the surface finish line without shedding a wheel, understanding these measurements is definitely step one.
A lot of people see the block and immediately think about what exactly they want to cut aside, but it's actually essential to know what you can't change. The track has extremely specific physical limitations, and if your own car ends up as well wide, too long, or too low, this simply won't run. Let's break straight down what you're really looking at when a person pull that wood out of the particular box.
The conventional Measurements You'll Discover in the Package
A standard official BSA pinewood derby block usually measures 7 inches longer, 1. 75 ins wide, and 1. 25 inches high . It sounds pretty straightforward, but individuals numbers are actually extremely intentional. The 7-inch length could be the optimum allowed in most contests, though you'll often see people cut a tiny bit off the back again or front to accommodate specialized bumpers or weight storage compartments.
The thickness is arguably the most critical dimension. At 1. 75 inches, the block is designed to sit perfectly on the track with no rubbing against the side-rails too very much. If you choose to narrow the particular body for the "needle" style vehicle, you have to be careful. You still need enough wood at the axle points to maintain the wheels spaced properly. If the wheels are too near together, the car will straddle the center railroad and grind to a halt.
Then you've obtained the height. With 1. 25 ins, the block offers you enough "meat" in order to carve out a wedge, a smooth sports vehicle, or even something goofy such as a hot doggy or a school bus. Most speed-focused builders end upward cutting away the massive chunk of this height to reduce the center of gravity, often leaving the vehicle only about half an inches thick at the tallest point.
Why Those Precise Inches Matter
You might wonder why we're getting so picky in regards to a piece of pinus radiata. Well, the monitor itself is a fixed environment. Most pinewood derby monitors possess a center guideline rail that's about 1. 625 inches wide. Since your own block starts at 1. 75 ins wide, you have just enough clearance to match the wheels on the outside while the body of the vehicle clears that middle rail.
In the event that you mess with the dimensions of pinewood derby block without the plan, you run into "clearance" problems. For example, the distance between your bottom part of the car plus the track surface area (the "ground clearance") needs to be at least 0. 375 inches (3/8"). If you include weights to the particular bottom of the particular car and they will stick out too much, the car will scrape against the center rail. Nothing kills speed faster than friction, and nothing creates friction faster than the car dragging the belly throughout the monitor.
Dealing with the particular Axle Slots
If you go through the bottom of the block, you'll discover two grooves cut into the wooden. They are the axle slots. In the standard kit, these are usually spread about 4. twenty five inches apart. This particular "wheelbase" is a huge factor in how the car holders.
Some scouts like to drill down new holes rather of using the slots to ensure the axle assemblies are perfectly straight. However, many race rules require you to make use of the original slot machines. If you're permitted to move them, people often extend the particular wheelbase (moving the particular wheels further toward the ends of the car) to help make the car more steady. But even then, you have to respect the overall dimensions of pinewood derby block rules—the wheels can't stay out past the front or back of the 7-inch limit.
It's also worth noting that this slots aren't always perfectly rectangular through the factory. I've seen plenty of kits where 1 slot is slightly crooked. Checking this particular before you start carving is usually a lifesaver. In the event that the slots are crooked, your vehicle will "dog-track" (drive sideways) and strike the rails constantly.
Weight Submission and the Remaining Wooden
While the particular exterior dimensions are usually fixed, what you are along with the internal volume of that will wood is where the magic happens. The particular goal is almost always to reach exactly 5 oz. A raw block of pine usually weighs somewhere about 3. 5 to 4 ounces depending on its wetness content, but once you start cutting it into a cool shape, that weight drops significantly.
Because you're removing so much wood, you have to include weight back in—usually in the type of tungsten or even lead. Knowing the dimensions of pinewood derby block can help you figure out there where that weight may go. Most pros want the middle of gravity to be about 1/2 inch to at least one inch in front of the rear axle. What this means is you require enough wood thickness in the back again of the car to drill openings for the weights with out snapping the car in half.
If you slice the car down to a paper-thin sliver, you won't have got anywhere to cover the particular weight. I've seen some really cool-looking "wafer" cars that will ended up being incredibly fragile since the builder forgot they needed the place to place the tungsten.
Techniques for Cutting Your Block Without Ruining It
Prior to you have a found to the wooden, grab a pen and a leader. It sounds old-school, but drawing your design on the side and the particular top of the particular block first is usually the only method to stay within the particular lines.
- Don't filter the axle region: Maintain the full one. 75-inch width exactly where the axles go in. This provides balance and keeps the particular wheels from massaging your body.
- Watch the nose: Most tracks have the starting pin that will drops right down to begin the race. In the event that you make the nose of your car way too high or even too pointy, it might not sit right against the particular pin, or this might get caught when the flag drops.
- Leave some "meat" for the axle assemblies: If you cut the particular block thinner vertically at the factors where the axles use, the wooden might split when you try to press the nails in. You want a minimum of a quarter-inch of solid wood over the axle slot machine if possible.
Guidelines and Tech Examinations
Every race includes a "tech inspection" where someone along with a specialized container or a place of calipers bank checks your car. They're checking to make sure you didn't exceed the maximum dimensions of pinewood derby block limits. Usually, the car has to suit inside a container that is 2. 75 inches broad (including the wheels) and 7 inches long.
When your car is definitely 7 and 1/16th inches long because you added the fancy plastic vender on the back, you're going to be in the particular parking lot with a hacksaw five a few minutes before the race starts. It's way much better to build slightly below the maximum dimensions than to try and force it to the particular absolute limit plus get disqualified.
Wrapping it Upward
At the end of your day, the dimensions of pinewood derby block are presently there to give everyone the fair starting place. It's a standard canvas for a quite creative project. Once you realize that the 7" x 1. 75" x one. 25" box is your playground, you can begin focusing on the particular things that actually make the car fast—like wheel alignment, friction reduction, and fat placement.
Don't hesitate to get creative with all the form, but keep your current ruler handy. The car that looks like a lightning bolt but is too wide for the particular track is just a quite pretty paperweight. Stick to the dimensions, leave enough wooden to support your axle assemblies, and you'll be in great form when race day time rolls around.