Want to take it to the next level

Secrets, tips, tools, design considerations, materials, the "science" behind it all, and other topics related to building the cars and semi-trucks.
Speedster
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Re: Want to take it to the next level

Post by Speedster » Sat Jan 14, 2017 12:49 pm

5) The axles are usually cleaned with soap and water, dried, and then put in a dish with 91% alcohol (Walmart) and soaked for 15 minutes. This is to remove any moisture that might still be in or on the axles. Hopefully it will prevent rust from forming on the axles. We then coat our axles with Lemon Pledge (it smells good) and then apply a coat of graphite using a pin vice and a piece of wood with a "V" groove cut in one end. Graphite is put in the "V" groove. The axle is turned very slowly per instructions by Dr. John Jobe. The scouts believe this will make their car go faster. Who knows? Maybe it does, maybe it doesn't but they surely do like doing it.
Last edited by Speedster on Sun Jan 15, 2017 5:12 am, edited 1 time in total.



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whodathunkit
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Re: Want to take it to the next level

Post by whodathunkit » Sat Jan 14, 2017 7:40 pm

Vitamin K wrote:
BTW, if you're not /REALLY/ careful and really slow with polishing with Q-tips, it's easy to enlarge wheel bores. I know a lot of league racers have moved away from q-tip sticks for this reason..
And maybe why a lot of them have moved on to using the Tamiya spears for this reason.
Cotton swabs bought from the supermarkets usually have loosely spun cotton tips and shafts that quickly lose there shape.
The Tamiya brand spears are a models swab that have tightly spun cotton swab tips making them much better suited for hobby use.
Plus the middle sized spear are just smaller in size to the cotton swab shafts.. so it's much harder to enlarge the wheel bores
while using them for a wheel bore prep set up for running the oil lubes.
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What type of automobile can be spelled the same forwards & backwards?

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Vitamin K
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Re: Want to take it to the next level

Post by Vitamin K » Sat Jan 14, 2017 9:33 pm

BullFrog wrote:Another question. When using the silicone lube is it as critical to get the axels mirror finish if we will just be spraying them with silicone?
What's the best way to spray it on the axels? I worry about it clumping up.

Image
We usually polish to 2000 grit for Scout races. (3000 if I've got the racing bug and I'm sending a car in to the leagues.)

I find that the Max-Pro leaves a pretty even coat without a lot of fuss. I go outside to spray, then hold the axle at the point and spray the stuff onto it, turning it to make sure it coats all over the shaft and under the head. Then I shake off the excess and stick it into a block of wood with holes drilled to hold it upright while it dries. I usually put said block of wood into a tupperware container to keep any dust from settling on the axles.



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BullFrog
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Re: Want to take it to the next level

Post by BullFrog » Sun Jan 15, 2017 2:36 pm

Vitamin K wrote:
BullFrog wrote:Another question. When using the silicone lube is it as critical to get the axels mirror finish if we will just be spraying them with silicone?
What's the best way to spray it on the axels? I worry about it clumping up.

Image
We usually polish to 2000 grit for Scout races. (3000 if I've got the racing bug and I'm sending a car in to the leagues.)

I find that the Max-Pro leaves a pretty even coat without a lot of fuss. I go outside to spray, then hold the axle at the point and spray the stuff onto it, turning it to make sure it coats all over the shaft and under the head. Then I shake off the excess and stick it into a block of wood with holes drilled to hold it upright while it dries. I usually put said block of wood into a tupperware container to keep any dust from settling on the axles.
Thanks K. I went back in this thread to take some notes and you had already covered this topic. Oops



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Re: Want to take it to the next level

Post by BattleBorn » Sun Jan 15, 2017 8:13 pm

LightninBoy wrote:1) It is most important to extend the rear axle back as far back as you can (typically 5/8in from the back edge of the block). After that, opinions vary on where to place the front axles. If you want a more stable car opt for a longer wheelbase. If you want to maximize kinetic energy opt for a shorter wheelbase. I advise scout cars to use a 5" wheelbase, meaning the fronts axles are 5in from the rear axles (which are 5/8in from the back edge). That's a good compromise. I definitely would go no more than 5.25in and no less than 4.75in.

2) Weight placement affects center of mass and, yes, it is critical. 1" COM is a popular rule of thumb but that is on the conservative side. With a 5in wheelbase I'd shoot for .75in. Again, the trade off is that the longer COM is more stable but provides less energy.

3) It works. Just remember to run the drill SLOW. Too fast and you will ruin the wheelbores. If you don't have something already, get a magnifying glass to inspect the bores and see the before and after.

4) What makes you think you took off too much? Unless you used a file or really course grit sandpaper, I wouldn't worry about it.

5) No. BTW - I never use alcohol to clean the wheels and axles. Soap and water works fine.

6) There really isn't a "standard" pinewood derby. The rules are different everywhere. That said, its probably more common for oil to NOT be allowed. Which is a shame, because its so much cleaner. Our council rules (Northern Star Council) allows both, but strongly recommends oil over graphite.
1) Ok so I was way off, I was using the predrilled extended wheelbase which is over 6". I follow the logic behind the greater stability with the longer wheelbase but I'm not following how the shorter wheelbase increases speed? I'm using the Stealth car from hobby-lobby (http://www.hobbylobby.com/Seasonal/40%2 ... ns/p/26216) so my only concern is if I reduce the wheelbase to 5" it may bring the front of the car too low. ...I may end up having to change car designs which is fine, I have time.

2) I've been using the screw-in weights (http://www.pinewoodpro.com/p/021319.html) so it's fairly easy to dial in the center of mass.

3) I will give it a shot I just picked up the swabs from walgreens :)

4) Yeah I used a file at first all the way down to 30 micron. I was very careful not to take off too much with the file, only enough to remove the burrs but at the end it just looked like I took off too much and the wheels seemed a bit wobbly but this is really subjective, I'm going to buy a micrometer to confirm.

6) What's the difference in axle prep between oil and graphite?

Thanks!



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Re: Want to take it to the next level

Post by BattleBorn » Sun Jan 15, 2017 8:20 pm

Vitamin K wrote:I'll add my piddly thoughts in addition to LB's. :)

4) If the wheel is wobbly, I'd suggest you check the bore. Some wheels are cast tighter than others. If a wheel wobbles excessively, try a different wheel on the axle. If that wheel spins true, I suggest you get some more wheels. BTW, if you're not /REALLY/ careful and really slow with polishing with Q-tips, it's easy to enlarge wheel bores. I know a lot of league racers have moved away from q-tip sticks for this reason.

5) Graphite likes to fly off. I add graphite as a two-step...first I try to burnish it into the hubs and bore (plenty of how-to on this) and then I'll actually add another coating of graphite in the wheel/axle interface. I actually use two different kinds of graphite...a fine, pure graphite (Max-V in my case) for burnishing, and a coarser, graphite/moly blend for the final lube (Hob-E-Lube, in my case). One more thing you might consider is giving the axles a pre-treatment spray of Pledge or Sailkote, if your rules permit this.
4) Yep, I'm going to try some new wheels and buy a micrometer to measure the axles to be sure.

5) I think I could use the sailkote since it's a dry lubricant, I don't think this would be in violation of the rules. I assume the sailkote would be preferable to the pledge?

Another question, what do you guys use to repair damage to the cars? Is there a pinewood derby equivalent of bondo? :) I've been letting my son do more work on this car himself and we have some damage to repair!!

Thanks!



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Vitamin K
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Re: Want to take it to the next level

Post by Vitamin K » Sun Jan 15, 2017 8:24 pm

BattleBorn wrote:
Vitamin K wrote: 5) I think I could use the sailkote since it's a dry lubricant, I don't think this would be in violation of the rules. I assume the sailkote would be preferable to the pledge?

Another question, what do you guys use to repair damage to the cars? Is there a pinewood derby equivalent of bondo? :) I've been letting my son do more work on this car himself and we have some damage to repair!!
I don't have first-hand experience, but if you search the archives here, you'll find some folks detailing their experiences with Sailkote. It sounds better than Pledge to me, but I don't have a lot that's concrete to go off of.

What sort of repairs do you need to do to the car? For splits and cracks, I've gotten a lot of mileage out of 5-minute epoxy. FWIW, there's nothing to stop you from using actual Bondo to fill dents and gaps, is there?



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Re: Want to take it to the next level

Post by BattleBorn » Sun Jan 15, 2017 8:32 pm

Vitamin K wrote:
BattleBorn wrote:
I don't have first-hand experience, but if you search the archives here, you'll find some folks detailing their experiences with Sailkote. It sounds better than Pledge to me, but I don't have a lot that's concrete to go off of.

What sort of repairs do you need to do to the car? For splits and cracks, I've gotten a lot of mileage out of 5-minute epoxy. FWIW, there's nothing to stop you from using actual Bondo to fill dents and gaps, is there?
He was doing something with the axle and cracked the hole and about a 3/4" of wood below it and I couldn't find all of the broken pieces or I could probably just glue it back. I'll give the epoxy a shot, since I think I have a better shot of re-drilling the axle holes with the epoxy.



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Re: Want to take it to the next level

Post by Vitamin K » Sun Jan 15, 2017 8:54 pm

BattleBorn wrote:
Vitamin K wrote:
I don't have first-hand experience, but if you search the archives here, you'll find some folks detailing their experiences with Sailkote. It sounds better than Pledge to me, but I don't have a lot that's concrete to go off of.

What sort of repairs do you need to do to the car? For splits and cracks, I've gotten a lot of mileage out of 5-minute epoxy. FWIW, there's nothing to stop you from using actual Bondo to fill dents and gaps, is there?
He was doing something with the axle and cracked the hole and about a 3/4" of wood below it and I couldn't find all of the broken pieces or I could probably just glue it back. I'll give the epoxy a shot, since I think I have a better shot of re-drilling the axle holes with the epoxy.
I would epoxy the broken wood back into place. For the axle hole, clip the pointed end off of a toothpick, roll it in epoxy and insert it into the hole. Then clip off the excess and sand it smooth after the epoxy cures. That will give you a better medium to drill into.



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Re: Want to take it to the next level

Post by Speedster » Tue Jan 17, 2017 10:29 am

BullFrog, Might we back up a bit ?
I do not know all your rules but I suspect they are very lenient. The block you have is 1 3/4" wide and 6 5/8" in Length. I do not know the thickness but the picture suggest it's not very thick. You never want the block to be less then 7" long. This is physics involving "The Cycloid of Constant time". The rear axle should be 5/8" from the rear of the car. This is as far as you can go because more than that and the wheel will stick out past the rear of the car. Recommended weight for an extended wheelbase car is 2 ounces behind the rear axle slot. You have 5/8" to work with. The screw in weights are 3/8" in diameter and 3/4" in length. They weigh 1/2 ounce each. They recommend drilling certain size holes in the back of the car toward the front. There's not enough room to do this and you would hit the axles after drilling 5/8" into the wood. Lead is not dense enough to accomplish what you want to do and neither are 3/8" tungsten cylinders unless you start going up in the air. 1/4" cubes and tungsten plates are the only things that come to my mind that will give you what you want to do. 4 tungsten plates weigh 2 ounces.
If allowed, I would buy aftermarket BSA axles from Maximum velocity. If there are no rules on axles then by all means go with Stainless Steel.
Harbor Freight often sells Electronic Digital Callipers for $10.00. Even at regular price they are still cheap. Callipers should give you what you want.
I wish you and your team the Very Best.
Speedster



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Re: Want to take it to the next level

Post by BullFrog » Tue Jan 17, 2017 2:27 pm

whodathunkit wrote:Good Info VK & Speedster!

BullFrog,
A word of caution that i'll pass on is this ..
I don't know if Speedster forgot to say something about shaft sizes of the studio 35 swabs running wild for sizes in the box:
he may or may not be experiencing this with his stock.
Some of the older walgreens 625 swab shafts ran wild for sizes 0.099 up to 0.104 back when you could get them before the change over to studio 35 swabs
at Walgreens.

Now I can't talk for Speedster on this but watch out and check the shaft sizes:
As you may think there all the same in size when they may or may not be .

Some Tip's I'll pass on to check the shaft sizes:
Image

For a quick way to check size's and then maybe re size the shafts is to use a decimal equivalents number size dill gage machine screw tap & wire gage.
You know how you can resize wooden dowel rods with them.. same might go for shaving down the paper shafts if there to large and your in a pinch not to waste them. However use your best shafts in the same size that haven't been shave down..( paper will be smoother!)
So I mic'd a bunch of the Walgreen swabs today and they were .098 to .100. Anything over .099 went into a separate piles. They will be used for ears not pinewood Derby wheel bores :mrgreen:



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Want to take it to the next level

Post by whodathunkit » Tue Jan 17, 2017 3:53 pm

Another tip for cutting the swab end's off the spindles clean is to use a good pair
of toenail clippers.
Watch out for jagged ends on the spindles there killers on wheel bores if spun down into the bore.

If you see a lot of black on the spindle or chunks
of plastic falling out of the bore your bore..
Is trashed!
So turn the spindles slow and listen to the squeaking sounds close.

Good luck.
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What type of automobile can be spelled the same forwards & backwards?

BattleBorn
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Re: Want to take it to the next level

Post by BattleBorn » Fri Mar 31, 2017 8:38 am

I was curious what you guys thought of this method of axle lubrication? He mixes graphite and alcohol into a paste and then packs it into the wheelbore. I've never seen this strategy before just curious what the Pinewood guru's thought? :)

https://www.youtube.com/watch?v=TPLSz-st5LM



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Re: Want to take it to the next level

Post by BattleBorn » Fri Mar 31, 2017 8:41 am

Speedster wrote:The problem I see in trying that product is there is no way in ever knowing if it helped you or hurt you. Let's consider the system I learned from others. First,we do not sand the axles. OK, I did not learn that from anyone else. We polish the axles with Brasso and a Dremel tool and then coat them with Lemon Pledge....
Hi Speedster, did I read you correctly? You don't sand the axles on a drill? Isn't it difficult to keep the axle true using a freehand Dremel?



Speedster
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Re: Want to take it to the next level

Post by Speedster » Fri Mar 31, 2017 1:00 pm

Keep in mind the nail does not turn.
I don't sand the axles at all. I remove the casting marks under the head with a 3 corner file by mounting the nail in the drill press. I do not turn on the drill press. I carefully file the casting marks away. I then polish the Zinc coating with Brasso with a cotton attachment on my Dremel at High Speed. Then the Lemon Pledge, buff it lightly and then the graphite. I have never used oil. I think it's hard to improve a stock BSA nail by sanding it.
You might consider I might be the only one treating BSA nails this way. You choose what is best for you and your team.
Best
Speedster



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