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Royal Rangers shaving ranger wheels

Discussion in 'Awana Grand Prix, Royal Rangers, and Royal Racers' started by kickaxe, Mar 13, 2015.

  1. kickaxe

    kickaxe Pinewood Ninja

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    Vitamin K asked me to share how I shave my razors.

    Note:
    I do also shave scout wheels when I build cars to show my students the difference wheel mass makes at the finish line. For those who have not read my previous posts, I am an 8th grade physics teacher who uses pinewood derby cars accompanied by a technical journal as my students' final exam for my class. The kids each build a car and I help them discover the force, inertia, friction types (and reduction), velocity, acceleration, average speed, etc.

    Back to shaving wheels without a lathe.......

    Materials needed:
    [list type=decimal][*]Drill press set at low speed[*]Pro Wheel mandrel (I buy mine at Maximum-Velocity but most hobby shops have one) [​IMG] [*]2 small washers to use with the mandrel between the shaft and screw so it does not reshape or scratch the bore of the wheel.[*]wood rasp like this one [​IMG] [*]wire brush to clean the rasp[*]utility knife with a fresh blade[*]1000 grit sandpaper[*]plastic polish[*]leather or soft cloth to apply polish[/list type=decimal]
    Process for Ranger wheels

    Ranger wheels are solid chunks of plastic, instead of the hollowed out ones. They are heavy, the hole can be off-center, they are molded from the edges, and most of them have flaws in the plastic. Here is a before and after:
    [​IMG]
    I place the wheels in the mandrel between the spacers and screw it tight. Then I use the rasp to remove the plastic on one side of the wheel by keeping the rasp level (I have been known to tape the small yellow tubes inside bubble levels to the rasp to make it as perfect as possible) and applying gentle pressure. The plastic comes off in thin strands. As the plastic builds up on the rasp, I brush it onto the floor with a metal brush and continue shaving. Once the side of the wheel I am working on is flattened to the depth I desire, I use the utility level with the wheel surface to shave the rough surface. Be careful here not to melt the wheel. Slow and steady for no more than 6 seconds at a time. I then wet sand it (while still spinning) to polish it up. Once it is smooth, I remove the wheel, flip it over and repeat the process. When the wheel looks good, I use the plastic polish to really make them shine. Sometimes I drill holes in the finished wheels to lighten them up even more (These wheels are a softer plastic than the scout wheels, so I cannot go to thin).

    For the scout style wheels:

    I use the same mounting process, but I use the utility knife to first slowly carve the running surface off of the wheels by bringing the razor edge, held perpendicular to the wheel surface, in contact with the wheel to cut off the bulk of the wheel surface to get rid of friction. The remaining part of the wheel tread should be about 1-2 mm thick. I then smooth out the inner side of the wheel (the side facing the car) to a high gloss shine using the sandpaper and polish. This keeps the part that can contact the rail slick. I then use the rasp to remove material from the outer edge (hub cap looking area) of the wheel. I finish the job by sanding the area smooth and polishing as before.

    CAUTION........expect to destroy a few wheels in this process and expect this process to take time. It takes me about 15 minutes to make a really good wheel, but it used to take me about 30 minutes. It does get easier with practice.
     
  2. BulldogRacing

    BulldogRacing PWD Royalty 5+ Pro Race Wins! Pro Racer

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    how much faster do your 2 gram wheels go then standard un modified wheels with this process? Have you tried to do 2 gram wheels?
     
  3. Quicktimederby

    Quicktimederby PWD Royalty

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    Very interesting! I would be very interested in what the OD run-out is. Even with the "PRO" mandrel, (if you can call it that) it is nearly impossible to get the wheel centered in one of those things, and then once you get the wheel center in the mandrel than you got to get it centered in the drill. The finished product looks good just curious on how round your able to get the wheel in relation to the hub. I do believe you'll see performance from the weight reduction, but I know your leaving a lot on the table speed wise buy not turning the wheels on a properly set up lathe. I use to cut down BSA wheels like this and could get them in the 1.0 gram area, but then I bought a set of properly turned wheels that weighed around 2.3 grams and they were faster than the 1.0 grams that I made. Hopefully you'll have better luck than I. Nice job.
     
  4. kickaxe

    kickaxe Pinewood Ninja

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    Bulldog, not sure about exact numbers as lube, polish, tuning, etc can all alter results, but the lighter the wheels are, the faster the car will finish as long they stay round throughout the race. I find that the difference can be as much as .02-.04s (or more if the original wheels are out of round) on the Derbymagic track at the school. It is all about starting faster, which is also why running 3 wheels is faster than running 4 wheels. Less starting energy is wasted getting the wheels up to speed. I know TxChemist ran some numbers on a post where he concluded that it would take over 400 feet of track for heavier wheels or 4 wheel cars to catch a 3 wheeler using 2.6g wheels.

    Quicktime, I use the mandrel to reduce mass only. The wheel bores of the ranger wheels are 1/8 inch (very sloppy) and are waaaay to big for the mandrel to center them. I true the wheels round using a hand drill and sandpaper. I lay the drill on its back in a vise and use the end of the silver bullet on a drawer slide on a flat level surface next to a mm ruler to slowly slide a piece a of sandpaper to edge to round the wheels to make each wheel round and as close to the same size as possible. not perfect, but pretty close.To my knowledge, nobody supplies razors for Ranger racing.

    I agree that a proper lathe set up would be much more precise, but I do not have access to one. As far as scout wheels go, if I ever get the funds together to race a season in the NPWDRL, I would buy the DD4H wheels and axles to match the race entered, his precision is both guaranteed and legendary.....and I would need to focus on other details to even be competitive.
     
  5. B_Regal Racing

    B_Regal Racing PWD Royalty Pro Racer

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    Not trying to browbeat you into racing, but there is no other way to learn other than racing, even if you come in last most of the time. While funds play a part in this hobby (as in any other hobby), I would say that time and dedication will play a larger role in getting faster. I respect every racer here, including those I beat (and those I lose to), as one day they'll be beating me.

    Just send a car in, not for a series, but for a race. You may just like it...
     
  6. Kinser Racing

    Kinser Racing ********************* 25+ Pro Race Wins! National Champion

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    Initial investment to get into this hobby can be less than $100 and the monthly to race less than $25.
     
  7. kickaxe

    kickaxe Pinewood Ninja

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    No brow beating necessary B_Legal and Kinser, I am dying to race in the the league. However, as a single income science teacher with 4 kids under 12 the budget just does not allow for league competition. We chose to sacrifice so my wife could stay at home and raise our kids. The youngest should be in full time school in the next year or so and then we should become 2 income again. Then I can start this hobby full time instead of just Royal Rangers and a school project.

    I may send in one of my cars from my school race just to race in a single race, but I cannot race a full season. For the students in my classes, we use Max-V car kits so I can keep the costs to less than $8 per student for their kit, pre-molded lead weights, polishing papers, metal polish, sticks, sandpaper, krytox, silicone spray plastic polish, etc......... I know the kits are inferior to what is for sale here though.

    BTW Kinser, I have been on this forum since it started and I have say it is great to see you back at top form. Congrats on owning 3 track records and thank you for all of the advice and time you give to all builders.
     
  8. TRE

    TRE PWD Royalty Pro Race Winner Pro Racer

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    I must be doing something wrong
     
  9. Kinser Racing

    Kinser Racing ********************* 25+ Pro Race Wins! National Champion

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    I know you have kickaxe. I was just an overall statement to all who might read it. /images/boards/smilies/smile.gif

    TRE, ya I missed that one. It's probably right close to a buck and a half though (minimal).
     
  10. ngyoung

    ngyoung PWD Royalty

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    Shipping my 1 car from MN it is $11.08 in shipping for both labels plus the $10 entry fee. My shipping box is less then 12" in any direction and total weight is less then 1lb. Going with a bigger box containing 2 car carriers is around 3lbs and I think $13 total for shipping both ways.

    I would encourage you to enter some of your razor wheel cars into the eliminator class. You may have to make new bodies, not sure is RR has the same dimension and weight, but it looks like you may have plenty of wheels to pick a good set to race with.
     
  11. kickaxe

    kickaxe Pinewood Ninja

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    Thanks for the vote of confidence Ngyoung. However, my razors are made from the RR kit and have a 1/8 inch inner diameter. While they are very fast for ranger races, they are awful compared to scout wheels. This year was the first year I made a 6 oz. Ranger go as fast as my Max V cars. I will apply what I have learned from this years build to the scout car style when I build one to race with my students. I will start putting money aside to see if I enter the summer series for BASX running the Max V kit. It should theoretically be slower than the cars running stainless steel axles and DD4H trued wheels, but worth it to race.
     

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