Pack 335 Pinewood Derby 2013Rev up!
What is Pinewood Derby The Race  For cub scouts and their parents & siblings too! The Track  Most packs have their own...
The Science Behind ItMomentum, gravity, slope/angle of the tracks, weight of thecar, friction, aerodynamics, balance. Wha...
Car weight = momentum Maximum weight of fully assembled car can be 5 oz. Weight types:  Low density metals = need more,...
Car weight = momentum What to weigh  Weigh all parts (car body, wheels, axles, accessories, additional weight)   before ...
Reduced friction = speed The most friction comes from the wheels brushing against the axles  and the tracks Nothing much...
Sleek, smooth shape = aerodynamics Some friction comes from the car brushing against the air Shape of the car  Go for d...
Sleek, smooth shape = aerodynamics Cross section (graph & chart) paper with inch markings works best –  plain and ruled p...
Balanced wheels = stability The track has a ridge in the middle – the guide strip   This keeps the cars from running off...
Safety First or Last or Somewhere Use safety glasses/googles during most of the work Use dust mask when cutting, sanding...
Tools Use a clamping vise – to hold car body, drill, etc. Use a rasp – for quick shaping Use a file – for finer finishe...
Impound night & inspection Test your car before impound night pack meeting (21st February) The box to check the cars – m...
See you at the finish line…              DelPradoPack335@gmail.com
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Pack 335 Pinewood Derby 2013

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  • The track - picture of the trackThe carsWinning (levels)And losing
  • 1. Wobbly wheels are not good for the racing cars and even other cars as it can get thrown off the track and bump into other cars causing a massive crash and damage2. We will re-run the heat in such situation but only if the cars can be fixed in a reasonable amount of time3. Make sure the glue does not run into the wheel bore
  • Both rasps and files come in different shapes – D, round, flat, etc.Rasp is a bit different from a file – there are individually teeth placed randomlyhttp://www.homedepot.com/webapp/catalog/servlet/ContentView?pn=Chisels_Files&storeId=10051&langId=-1&catalogId=10053Files and rasps are handy tools when it comes to smoothing and shaping. While some people use the terms interchangeably, there are distinct differences between files and rasps and each serves a different purpose. It is a common perception that files are best suited to metal applications while rasps are used only for wood, but this is not necessarily the case. In general, rasps are used for more aggressive work while files offer a slightly more refined finish. Of course, your selection will also depend on what grade and material you are working with and other factors as well. The large selection of available options can be a little intimidating, so consider the following questions as you seek to determine what file or rasp is right for you:What types of files are available?What types of rasps are available?What shapes do files and rasps come in?What do different grades indicate?What special features might be helpful?Files, Rasps, Shapes, Grades and UsageChoosing the right file or rasp depends largely on what material you're working with and how fine of a finish you need. In most cases, files and rasps serve as an intermediary step between rough sawing and finishing with sandpaper. Files and rasps can be used on wood, metal and plastic and may be used to sharpen mower blades and other tools, remove rust, deburr metal and more. Along with choosing a tool that has the best grade and configuration for the material you're working with, using the proper technique and keeping your tools clean during use is crucial to getting the job done right.Files: Files are characterized by parallel, diagonal rows of teeth that form ridges across the surface. Each of the sides is either cut, meaning that it has teeth, or uncut, meaning that it is smooth. Single-cut files have one set of teeth and are used to provide a somewhat smoother finish or create a sharp edge on knives, shears or saws. Double-cut files feature a second set of teeth that cut in the opposite direction and are used for more aggressive filing, shaping or removing rust from metal and smoothing wood. Curved-cut files are used for a variety of automotive applications, such as smoothing body panels. Rasp-cut files feature a series of individual teeth and are used primarily on wood. File lengths can range anywhere from 4" to 16" or longer and are usually available in increments of 2".Uncut edges are also called safe edgesUse light pressure when working with single-cut filesUse heavier pressure when working with double-cut filesCurved-cut files feature curved contours across the face of the fileCurved-cut files can also be used for working with plaster and fiberglassRasps: Unlike files, rasps have individual teeth that are often randomly placed to provide a faster, rougher cut. Use them to remove material quickly, particularly when working with wood. Wood rasps have a very coarse surface and are used primarily for quick removal of stock. Cabinet rasps come in handy for finer, more delicate work, such as creating a proper fit for mortise or tenon joints. Rasps tend to clog less frequently than files because of the way the teeth are designed and spaced.Horse rasps are used for working on horseshoesPatternmaker's cabinet rasps provide a smoother finishCabinet rasps can be used on wood of all types, leather or soft metalsShapes: Files and rasps come in several different shapes, each of which offers a unique set of advantages for different tasks. The chart below describes the most common shapes as well as what activities they're best suited for.ShapeDescriptionUsesFlat, Mill or HandFeatures straight edges and a flat surface with a series of parallel teeth.General tasksFlat files taper in width and thickness from the middle outwardMill files taper in width and thickness all the way throughHand files taper only in thickness and feature a square pointHalf-RoundFeatures both a flat face and a curved face.Concave surfaces, edges and holesFlat face can be used for filing flat surfacesCurved face is ideal for use on groovesRoundCircular design features teeth all the way around. Also called "rat-tail."Enlarging round openingsRemoving burrs from metalSquareFeatures four cut sides.Enlarging rectangular openingsTriangularFeatures two cut sides and one uncut side. Also called "taper" or "threesquare."Working on acute internal anglesSquaring cornersFiling groovesSharpening saw teeth and other toolsGrades: Files and rasps are both available in varying grades, or levels, of coarseness. File grades are often broken down into bastard cut, second cut or smooth cut. Bastard cut is the coarsest grade and is used to remove material quickly. Second cut can also be used for fast removal, though it provides a slightly smoother finish. Smooth cut features a fine grade that's ideal for finishing work and preparing surfaces for sanding. Rasps also come in a variety of grades, including bastard, cabinet and wood. In their case, however, bastard is the finest grade, with cabinet and wood rasps providing a coarser finish.In general, larger files and rasps are coarser than smaller ones, even if they have the same gradeSecond cut is sometimes referred to as medium cutCabinet cut is sometimes referred to as medium cut as wellCabinet- and wood-grade rasps remove material quicklyUsage and Care: As with all tools, proper care and technique is the key to safe and effective use. Choose the right combination of shape, size and grade for the project you're working on. When filing or rasping, push outward across the surface with a level of pressure appropriate for the material you're working with. Lift the tool at the end of the stroke and bring it back to the starting position before allowing it to touch the surface again. Working in only one direction will provide a higher quality finish and prevent the teeth from dulling too quickly. After a while, files will become clogged. Cleaning them with a wire brush or file card will help keep them in working order.Work in a well-ventilated area and use respiratory protection if necessaryRubbing chalk on the surface of a file or rasp can help prevent cloggingKeep files in protective sleeves or slotted racks to prevent them from scraping against each other when not in useFeaturesHandles: In most cases, rasps and files do not come with handles. Holding onto the bare tang can be uncomfortable, so you'll need to purchase a handle for each one. Look for ergonomic handles with rubberized grips to provide greater comfort. You can also purchase a universal handle, which features inserts that allow it to be used with different shapes.4-in-1 Tool: For maximum versatility, look for a multifaceted tool that allows you to tackle a number of different tasks. Some files are designed with both round and flat surfaces and with two different ends, one of which is a file while the other is a rasp.File Card: Keeping files and rasps clean is one of the keys to ensuring high-quality work. A file card is designed to get in between the teeth to clean out sawdust, metal shavings and other debris to keep your tools in proper working order.Diamond File: These files feature ground diamond particles, making them well suited to industrial applications. Use them when working on fiberglass, epoxy and other hard surfaces. Smaller diamond files will work well on glass, ceramic and various metals.
  • The end
  • Pack 335 Pinewood Derby 2013

    1. 1. Pack 335 Pinewood Derby 2013Rev up!
    2. 2. What is Pinewood Derby The Race For cub scouts and their parents & siblings too! The Track Most packs have their own set of wooden or aluminum racing tracks Typically 3 or 4 cars run on each track lane at a time – called a “heat” The electronic scoreboard at the finish line displays the heat results Each car races in each of the lane – to neutralize lane instability The Cars BSA certified kits only Add-ons can include weights, paint, decals, accessories within the BSA guidelines Winning (levels) Top 3 in each Rank (Tigers, Wolf, Bears, Webelos I, II) get a trophy!! Top 3 of each rank race for top 3 Pack positions Top 3 in each pack race at Council level (April) and beyond… And losing Scout must be present at the time of racing Getting disqualified at inspection on impound night DelPradoPack335@gmail.com
    3. 3. The Science Behind ItMomentum, gravity, slope/angle of the tracks, weight of thecar, friction, aerodynamics, balance. What you start with: A 7” x 1 ¾” pinewood block, 4 wheels, 4 axles What you CANNOT change: Slope of the tracks…its pre-built! Gravity…sorry can’t do much about it on our planet (yet) What you CAN change: Car weight = momentum Reduced friction = speed Sleek smooth shape = aerodynamics Balanced wheels = stability That is why you add weights, make all moving parts smooth and sand and sand and sand… DelPradoPack335@gmail.com
    4. 4. Car weight = momentum Maximum weight of fully assembled car can be 5 oz. Weight types: Low density metals = need more, takes lot of space High density metals = need less, takes less space Options: Zinc – low density = need more, easily available (Michaels) Steel – more density, cost effective, easily available (check your garage!) Lead – higher density, poisonous (use gloves), cost effective, buy in hobby stores Tungsten – highest density, very costly, buy in hobby stores or online Even the paint adds some weight! (0.01 oz. to 0.08 oz.) DelPradoPack335@gmail.com
    5. 5. Car weight = momentum What to weigh Weigh all parts (car body, wheels, axles, accessories, additional weight) before putting it together) – get it to 4.9 or 4.95 oz. Even the paint adds some weight! Where to weigh Use a kitchen weigh scale that has ounce measurement Take everything to a post office OR grocery store OR check with neighbors OR get in touch with me Where to put the weight You can add/attach weights anywhere on or in the car body Ensure the finished car does not exceed: 2 ¾” in width; 7” in length; about 5” in height and bottom clearance is at least 3/8” Some zinc weights are designed to fit under the car (like ones in Michaels) Weights must be firmly attached (no tape) DelPradoPack335@gmail.com
    6. 6. Reduced friction = speed The most friction comes from the wheels brushing against the axles and the tracks Nothing much can be done for the friction with the track The axles have burr and crimp marks Use a thin file to remove the burr under the axle (nail) head Use the same file to remove the crimp marks Then use a sand paper/cloth to even out Recommend using steel polish for the extra speed Test your work Insert the wheel onto the axle, add some graphite (only dry lubricant is permitted) Hold the axle horizontally and give it a few spins The wheel should spin freely for a few seconds DelPradoPack335@gmail.com
    7. 7. Sleek, smooth shape = aerodynamics Some friction comes from the car brushing against the air Shape of the car Go for designs that allow the air to disperse Smoothness of the car surface Fill the gaps and uneven areas with wood putty/filler – let it dry Sand the car body with coarse and fine sand paper before applying the paint Accessories Choose accessories (cabin/cockpit, drivers, engines, etc.) that are rounded Front of car Do not make the front too pointy A-shaped or V-shaped as this will be a problem with the starting device on the track DelPradoPack335@gmail.com
    8. 8. Sleek, smooth shape = aerodynamics Cross section (graph & chart) paper with inch markings works best – plain and ruled paper are fine too Mark the outline of the car’s wooden block and the axle positions on the paper Draw your design - side and top view Front of car Do not make the front too pointy A-shaped or V-shaped as this will be a problem with the starting device on the track Sharp tip can slip Car body cannot beyond starting line exceed starting line DelPradoPack335@gmail.com
    9. 9. Balanced wheels = stability The track has a ridge in the middle – the guide strip  This keeps the cars from running off the track or into each other!  But if the wheels brush against this guide strip then it will slow the car down  Wobbly wheels can even brush against the car body itself  Maintain width of 1 ¾“ at axle slots where wheels are to be mounted How to avoid this  Make sure the axles are straight  Make sure the axles are inserted at a perfect right angle (90 deg.)  After putting the wheels on, tap the axles in and close to the car body using a screw driver and light hammer  Glue is not really needed, although it does secure the axles in place  Do NOT put glue until you are satisfied with the car and its alignment Keep the car weight balanced just in front on the rear wheels  Make sure it is easy to tell the front side of the car  If the design is even – mark the front using a permanent marker DelPradoPack335@gmail.com
    10. 10. Safety First or Last or Somewhere Use safety glasses/googles during most of the work Use dust mask when cutting, sanding, spray painting, etc. Use gloves while handling lead weights and as appropriate Ask older scouts about “the blood circle” from their whittling chip experience Get a parent to help with all power tools whether running on mains supply and battery DelPradoPack335@gmail.com
    11. 11. Tools Use a clamping vise – to hold car body, drill, etc. Use a rasp – for quick shaping Use a file – for finer finishes to the shape Use a T-square – for perfect right angles Other tools: chisel, hammer, screw driver, coarse and fine sand paper For the more enthusiast souls Dremel has a range of tools and accessories useful for this and many hobby project Sanding belt DelPradoPack335@gmail.com
    12. 12. Impound night & inspection Test your car before impound night pack meeting (21st February) The box to check the cars – max. width 2 ¾“; max length 7” The weighing scale – max. 5 oz. Clearance – At least 3/8” Starting devices, washers, wheel bearings, bushings, change in axle positions, loose parts, springs, oil lubricants are strictly prohibited Official pinewood BSA wheels, axles, pinewood cars (accessories can be of any solid material, plastic, metal, fiber glass, other types of wood) DelPradoPack335@gmail.com
    13. 13. See you at the finish line… DelPradoPack335@gmail.com

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