The BSA nail

Secrets, tips, tools, design considerations, materials, the "science" behind it all, and other topics related to building the cars and semi-trucks.
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Speedster
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The BSA nail

Post by Speedster » Sun Mar 01, 2020 4:51 am

What is it we are asking the nail to do? What is done to that nail by racers in an effort to achieve their goal?

I'll call it the Extremes.

1. Sanding with 6 grades of sandpaper, removing all casting marks, polishing with Brasso,, soaking in 91% alcohol for 15 minutes, covering with Lemon Pledge, buffing the Lemon Pledge, adding graphite, put in a sandwich bag with a moisture remover.

2. Remove casting marks under the head of the nail.

Whatever is done to the nail is either going to make it better or worse toward the goal. It will never be the same as it was when it came out of the box.

What have you done to the nail?
Did it make it better toward your goal?

PROVE IT.

A Reminder. The nail doesn't turn.



Kenny
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Re: The BSA nail

Post by Kenny » Tue Mar 03, 2020 10:26 am

This was my Sons final axle prep process as a Webelos II Scout, much of it improved and adapted over time using methods from me (Dad), who raced in an adults-only class. I will only post the things our Pack and District rules allowed (or didn't explicitly forbid) for competing Scouts. Your Pack and District rules may be different, and you'll need to adapt for them. We were permitted to race 3-wheels down. We raced on 48ft Aluminum tracks.

Important Caveats
Some of these tasks are quite advanced. Young scouts cannot safely perform many of the steps as Tigers. But, as they get older, they can do a lot -if they are willing to work - if you take the time to help them. SOAPBOX: If you build your kid's car, they know it, all the kids will know it, and it's just not the same. Let them do it with your guidance. I might add that it's an incredible teaching opportunity and priceless time with your kid. OK, end of soapbox.

Not all people have access to lathes and drill presses, dial indicators and micrometers, but if you start networking, you'll find someone who does, and they'll almost always be willing to help you. Nearly all tasks can be performed on a regular bench using standard power or hand tools. Achieving the finest tolerances require some real ingenuity, but can be accomplished inexpensively.

Some steps, like polishing axles, can be done safely by some young boys while others may need your help. You'll have to be the judge. In our case, we had an open class for adults and Boy Scouts, which was separate and distinct from the boys' age-based racing classes.

Initial Smoothing
First came precision grinding down the casting using a Dremel tool. We want to knock down any junk on the underside of the nail head and any metal proud of the shaft. A mini-lathe would work superbly for this step, but we never had access to a lathe. After all the bumps and protrusions are ground down, we progressed to spinning the nail and smoothing using it using Emory cloth in a progression of grits 2000, 4000, 6000, 12000.

We always tried to remove as little material as possible using a progression of Micro-Mesh precision abrasives cut into strips to 12,000 grit with nail mounted straight in a drill press or mini-lathe and then checked (runout) for straightness. I cannot stress enough how light the pressure used at these stages. We spun the axle at very low speed to avoid heating it up and also to minimize material removal. Once casting marks are smoothed off and verified visually using a 20x loupe, we gave a slight convex slope to the inside of the nail (axle) head.

We plated the nail with nickel. Plating is relatively easy, and your Scout will learn some more neat stuff. After plating and again verifying smooth visually, and thickness using a micrometer, the axle is ready for polishing.

Polishing
The axle gets polished using Mother's Mag Polish applied at a slow speed using old tee-shirt cotton strips loaded with a small amount of polish cream. Once the cotton strip turns black, a new clean cotton strip is used to buff out the axle, keep buffing with clean strips until it's clean, and you can see yourself in it and no more black on the cotton cloth. The objective is to achieve a smooth mirror polished surface completely so that no matter where the wheel hub contacts the axle it will meet a consistent and smooth surface.

Note that the point of the axle or nail, the part mounted in the drill, is not polished, but we do want to ensure that it's smooth and straight so that it moves without damaging the wood during alignment later.

Bends
Now we should have at least four, preferably more, axles that are straight and polished. They should be tagged and bagged with a measured diameter to later best match up with a known wheel bore diameter. One axle, the "rail runner" steering axle, is precision bent 3 degrees; the three others bent 2 degrees. After verifying the bend, each head is marked with a color-coded reference for alignment later.

Lube
The axles get good cleaning with Everclear. Thoroughly dried, each gets a single drop of Krytox and all excess is removed. After this the car needs to be kept in a clean bag between alignment and testing and race check-in.

Multiple events treatment
After Pack racing, prepared for District by carefully removing all wheels/axles to clean, dry, and reapply lube No more than a week before the event. Keep each axles wheel combo together and replace them in the same hole/slot as before.

Results
My son was undefeated at the Pack level. Taking both his class and Grand Champion. Each year he competed. He won District the first time he competed first out of hundreds of entries. His car failed to finish the following year when his car jumped the end of the track during the first heat, which severely damaged it. That run was the fastest recorded at the event, so who knows?

I hope this helps. It was a nice trip down memory lane.



Speedster
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Re: The BSA nail

Post by Speedster » Thu Mar 05, 2020 5:32 am

Thank you, Kenny.
We cannot plate the nail with nickel but I'm glad you did that. That helps me to explain the point I was trying to make.

The BSA nail comes with a zinc coating. I feel the casting marks under the head should be carefully removed. THE END. Anything done to the nail after that will not make it better for the wheel bore to ride. I cannot prove that. Can anyone prove what they do to a BSA nail improves on the original Zinc coating?



Loud2ns
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Re: The BSA nail

Post by Loud2ns » Thu Mar 05, 2020 8:44 am

Speedster wrote:Thank you, Kenny.
We cannot plate the nail with nickel but I'm glad you did that. That helps me to explain the point I was trying to make.

The BSA nail comes with a zinc coating. I feel the casting marks under the head should be carefully removed. THE END. Anything done to the nail after that will not make it better for the wheel bore to ride. I cannot prove that. Can anyone prove what they do to a BSA nail improves on the original Zinc coating?
I have never used a bsa nail. Only Awana and aftermarket.

Sent from my SM-G950U using Tapatalk




Speedster
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Re: The BSA nail

Post by Speedster » Thu Mar 05, 2020 9:40 am

Loud2ns, Count your Blessings.



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whodathunkit
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Re: The BSA nail

Post by whodathunkit » Fri Jul 03, 2020 6:02 pm

What about grooving the axle shaft’s
Or tapering the axle head’s

What’s worked best for me is knocking off the
Burrs at the axle tips . So I don’t Destroy
The wheel bores while Inserting axles.
Last edited by whodathunkit on Fri Jul 03, 2020 6:09 pm, edited 1 time in total.


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

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whodathunkit
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Re: The BSA nail

Post by whodathunkit » Fri Jul 03, 2020 6:03 pm

Compound bends in the axle shaft!


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

Speedster
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Re: The BSA nail

Post by Speedster » Sat Jul 04, 2020 7:55 am

Live and learn.
This is the 1st time I have heard about "compound bends" in the shaft. Would you describe what is meant by that and what advantage it might give?



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whodathunkit
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The BSA nail

Post by whodathunkit » Sat Jul 04, 2020 5:22 pm

Sure Speedster!

A two plane bend or compound bend is defined as a compound bend.
In the plane view and a bend in the elevation.

Think of tube bending!

The nail axle is not a tube..however it is a round and a solid shaft much like tubing
that can be bent in many different angles.

Example..

Take your axle ,a screwdriver , and a hammer, and a vise.
You want to bend the axle to 1.5 degree.
So you place it in a vise and tap the axle to bend it
With the screwdriver and hammer.

You take it out of the vise to check your bend angle.
You find you need to bend it a little bit more.

So you do the best you can to place it back in the vise the exact same way it was.

However it’s not.. and its rotated some what now!

So you start tapping and bending it some more.

However you have rotated the axle somewhat when you placed it back in the vise
and now you have a compound bend in the axle shaft.

Is it helpful.. I don’t think so !
Last edited by whodathunkit on Sun Jul 05, 2020 3:36 pm, edited 2 times in total.


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

Speedster
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Re: The BSA nail

Post by Speedster » Sun Jul 05, 2020 4:50 am

Yep, that would be a compound bend. Thanks for the explanation.



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