How long do your wheels spin?

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BattleBorn
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How long do your wheels spin?

Post by BattleBorn »

I'm new to the pinewood derby so I've been watching some how to videos. I was able to polish some axles and they look and feel extremely smooth, true mirror finish. However, no matter how much graphite I put on them I can't get them to spin for the ~20s which I've seen called out in a few of the videos. The best I can do is about 12 seconds. I didn't polish the inside of the hub but visually they look extremely smooth, could that be it?

Another question I have is how do you get the graphite to stick to the axles? I put it on the there and it just seems to fall right off, I've washed everything with soap and water so they're very clean but I can't get the graphite to stay on them. I was wondering if that also might have something to do with it?
Speedster
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Re: How long do your wheels spin?

Post by Speedster »

Yes, that is it. Look at the hub with a magnifying glass. It isn't smooth. It should be polished with Novus 2 and a Walgreen's Q-tip. Some folks then apply certain waxes. Spending time on the wheel hub is far more important than spending a lot of time on the axle. Many believe the axle does not hold graphite. You can acquire a LOT of information, very detailed information, on Derbytalk by learning how to use the search function. Here's something you can play with just to see the difference. Buy a set of "Precision Turned Wheels" and a Knotty Racing "Wheel Runout Gage" from Derby Evolution and a set of 4094 axles from Maximum Velocity. Polish the axles with Brasso and a Dremel tool, wash them, dry them and put them in 92% alcohol (Walmart) for 15 minutes. I think I got that alcohol % correct. Learn all you can on wheel prep from the search function. Wheel spin time can be misleading but if you want to play with it, go ahead and have fun. Again, I urge you to use the Search function. There are a lot of experts that have provided techniques that work.
Best of Luck to you. Keep asking questions.
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whodathunkit
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Re: How long do your wheels spin?

Post by whodathunkit »

:welcome: BattleBorn,

Speedster is right about using the search function there is lot's of info on wheel prep.

There is also different types of graphite's with different particle sizes.. Some have (Moly) Molybdenum.
And then some are pure flake with a high ( 99% pure) medium to fine particle size.

Try using different types of graphite's with your wheel spin testing..
to see what particle size gives you the best spin times as well.
You'll want take a good look at the wheel bores and axles with your testing
to see what particle sizes and types are leaving scratches.
What type of automobile can be spelled the same forwards & backwards?
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Vitamin K
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Re: How long do your wheels spin?

Post by Vitamin K »

Pre-2009 BSA wheels were heavier than current BSA wheels, which means that they take more energy to spin, and thus will spin longer. If your recommendations on acceptable spin times are based on older wheels (that is, if the guide was published before 2009), this may account for some of the variation.

That said, most serious Derby racers invest a lot of time and effort into bore prep.

Here's a close-up of an unpolished bore: Image

Here's a polished bore: Image

Also, look into burnishing (search the forum for discussion on this). Related to what Whoda has said about varying types of graphite, I've heard tell that some works better for the burnishing part (usually the pure flake) while other works better to put between axle and hub (the stuff with added moly).

Good luck!
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Re: How long do your wheels spin?

Post by BattleBorn »

Speedster wrote:Yes, that is it. Look at the hub with a magnifying glass. It isn't smooth. It should be polished with Novus 2 and a Walgreen's Q-tip. Some folks then apply certain waxes. Spending time on the wheel hub is far more important than spending a lot of time on the axle. Many believe the axle does not hold graphite. You can acquire a LOT of information, very detailed information, on Derbytalk by learning how to use the search function. Here's something you can play with just to see the difference. Buy a set of "Precision Turned Wheels" and a Knotty Racing "Wheel Runout Gage" from Derby Evolution and a set of 4094 axles from Maximum Velocity. Polish the axles with Brasso and a Dremel tool, wash them, dry them and put them in 92% alcohol (Walmart) for 15 minutes. I think I got that alcohol % correct. Learn all you can on wheel prep from the search function. Wheel spin time can be misleading but if you want to play with it, go ahead and have fun. Again, I urge you to use the Search function. There are a lot of experts that have provided techniques that work.
Best of Luck to you. Keep asking questions.
Thanks Speedster, really appreciate the info. Out of curiosity, what's the difference between a Walgreens Q-tip and a Q-tip brand and why would that be better than say a pipe cleaner?
BattleBorn
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Re: How long do your wheels spin?

Post by BattleBorn »

whodathunkit wrote::welcome: BattleBorn,

Speedster is right about using the search function there is lot's of info on wheel prep.

There is also different types of graphite's with different particle sizes.. Some have (Moly) Molybdenum.
And then some are pure flake with a high ( 99% pure) medium to fine particle size.

Try using different types of graphite's with your wheel spin testing..
to see what particle size gives you the best spin times as well.
You'll want take a good look at the wheel bores and axles with your testing
to see what particle sizes and types are leaving scratches.
Thanks whodathunkit, I just bought the XLR8 Ultra Graphite and didn't give it a second thought, I can begin to tell that this whole pinewood derby thing is not a simple as I originally imagined, but this is good, lot's of good teaching experiences for my son, as soon as I learn them myself! :)
BattleBorn
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Re: How long do your wheels spin?

Post by BattleBorn »

Vitamin K wrote:Pre-2009 BSA wheels were heavier than current BSA wheels, which means that they take more energy to spin, and thus will spin longer. If your recommendations on acceptable spin times are based on older wheels (that is, if the guide was published before 2009), this may account for some of the variation.

That said, most serious Derby racers invest a lot of time and effort into bore prep.

Here's a close-up of an unpolished bore: Image

Here's a polished bore: Image

Also, look into burnishing (search the forum for discussion on this). Related to what Whoda has said about varying types of graphite, I've heard tell that some works better for the burnishing part (usually the pure flake) while other works better to put between axle and hub (the stuff with added moly).

Good luck!
Thanks Vitamin K, I just used the wheels that came with the car I bought them a few months ago so I'm sure I'm using the later wheels and now come to think of it that 20s spin guideline I know it was from a youtube video but I can't even find it anymore, information overload! :)
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whodathunkit
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Re: How long do your wheels spin?

Post by whodathunkit »

BattleBorn wrote: Out of curiosity, what's the difference between a Walgreens Q-tip and a Q-tip brand and why would that be better than say a pipe cleaner?
According to 5 kids Racing on a different topic:
The Walgreens brand 625 Q-tips run a couple of thousandths bigger in size. (for the steam.)
And the paper stem is less prone to scratch the wheel bores if the tip is sanded or rounded over
and used in a drill press.

The steams from both brands can also in-large the wheel bores or bind up in the bores..
from swelling of the wet paper stem if not done right.

Walgreens is also no longer carrying the 625 brand Q-tips that i know of..
if there the ones your asking about over the Q-tip brand.

As for the pipe cleaners.. the wire in the middle of cleaner can also be a killer on scratching the wheel bores.

Thanks to Vitamin K and his useful tip:
Of using a dab of hot melt glue on the end of the pipe cleaner wire..
the scratched wheel bore worries from the wire are now minimal . ;)

Then there are some builders that also like using the spears:
Some what to the liking of the Tamiya cotton swab spears..
for polishing the inner and outer wheel hubs as well.
Image

Best of luck BattleBorn & hope we all got your wheels spinning.
Whoda.
Last edited by whodathunkit on Mon Aug 31, 2015 9:20 pm, edited 2 times in total.
What type of automobile can be spelled the same forwards & backwards?
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Vitamin K
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Re: How long do your wheels spin?

Post by Vitamin K »

whodathunkit wrote: As for the pipe cleaners.. the wire in the middle can also be a killer on scratching the wheel bores.

Thanks to Vitamin K and his useful tip:
Of using a dab of hot melt glue on the end of the pipe cleaner wire the scratched wheel bore worries from the wire are now minimal . ;)
Can't take credit for that one. That's ngyoung's innovation.
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whodathunkit
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Re: How long do your wheels spin?

Post by whodathunkit »

Vitamin K wrote:Can't take credit for that one. That's ngyoung's innovation.
:doh: My bad.. Vitamin K,
I thought it was a tip that you came up with.. Thanks for keeping me on track.
And I'll find something on here to talk you up about.. can't blame me for trying anyway.
What type of automobile can be spelled the same forwards & backwards?
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Re: How long do your wheels spin?

Post by Speedster »

The shaft on the "studio35beauty" cotton swab from Walgreen's measures .099. The shaft on the Q tip brand cotton swab measures .102 which is too big. The wheel bore generally measures close to .096. It's best to check the shaft with a caliber because they vary a bit. I use a variable speed drill, run it slowly for 5 seconds with Novus 2, then check the bore with the magnifying glass from Derby Evolution. My drill press runs too fast causing too much heat. Heat will destroy the bore. The polishing makes a squealing noise. Always keep the hub and shaft wet with Novus 2. The extra fluffy pipe cleaners purchased on the internet seem to collapse when they get wet and I feel they're not doing what I want, but that's just me. There are several ways to prep a wheel and after you learn them all you'll decide what works for you.

When using the wheels out of the box you will likely get wheels that are .003 to .004 out of round. If you go to Maximum Velocity you will see the number of tools made specifically for building Pinewood Derby cars. These tools give an advantage. Railriders, built correctly, give an advantage. Having one of the aluminum tracks with a timer set up in your garage, gives you an advantage. Basically, anytime you deviate from the Laws of Physics the car will be slower. You might want to click on "Mid America Pinewood Derby" and see how close some of the times are. There is a book by Troy Thorne, 2013 addition, titled "Build a Winning Pinewood Derby Car"'. It is an Excellent book and written in a way both you and your scout will enjoy it. Michaels and Hobby Lobby generally carry this book at Pinewood Derby season. I notice it is presently not available on Amazon. If you have the knowledge it doesn't take a whole lot more time to build a fast car than a slow one. Sure, it's always fun to win but your scout will remember the time he spent with his Dad building the car far longer than getting a trophy. Make it Fun and make the car his. If you do that you've both won.
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Re: How long do your wheels spin?

Post by Speedster »

BattleBorn, I notice you stated you bought wheels several months ago. Where did you buy them ? Some wheels and axles are "Made in China" and carry the Official Boy Scout seal. Did you buy a tube of wheels or did you buy an Official kit? If you bought a tube, look on the inside of the wheel and see if it says, Made in China. If it does you do not want to use the wheels.
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Vitamin K
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Re: How long do your wheels spin?

Post by Vitamin K »

If you live near a BSA Scout Store, Troy Thorne's Book is being sold through the BSA now, too.
BattleBorn
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Re: How long do your wheels spin?

Post by BattleBorn »

Just picked up a copy of the book, great resource, thanks for the tip!


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Topspin.D
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Re: How long do your wheels spin?

Post by Topspin.D »

Thorne's book is really good. It's sort of like getting the Cliff's Notes for this message board. After you read it... look up "lemon Pledge trick" on this board for the last piece of the puzzle for fast graphite cars.
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