Hi,

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...

Any thoughts on how to build a fast car are welcome,
but I'm mostly interested in hearing ideas about how to prepare
the wheels and axles. The kit we have to use contains 2
steel axles of about 1/8" in diameter and four plastic wheels
whose hubs are a loose fit on the axles. Interference with
the body of the car prevents the wheel from moving axially toward
the car centerline. A plastic snap ring fitting in a groove at the
outboard end of the axle prevents the wheel from falling off
in the other direction.

Rules are nebulous. I think we're expected to use the
wheels and axles from the kit and the car can't weigh more than
8 oz. And that's it. This is a low key event, and I want this
to be a father-daughter project, so I don't want to go overboard.

What I have in mind is minimizing friction through judicious
alignment and smoothing and lubrication. Any suggestions
on how to accomplish this? What sort of lubricant should I
use?

Thanks for any and all ideas.

John Blinka

You, a master builder with a 100% win record, ask US for advise?? G

Preferred lubricant seems to be dry PTFE powder.
Micropolish the axles.
I'd balance the car weight so all wheels carry the same weight.
No other suggestions.

John Blinka wrote:
Hi,

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...

Any thoughts on how to build a fast car are welcome,
but I'm mostly interested in hearing ideas about how to prepare
the wheels and axles. The kit we have to use contains 2
steel axles of about 1/8" in diameter and four plastic wheels
whose hubs are a loose fit on the axles. Interference with
the body of the car prevents the wheel from moving axially toward
the car centerline. A plastic snap ring fitting in a groove at the
outboard end of the axle prevents the wheel from falling off
in the other direction.

Rules are nebulous. I think we're expected to use the
wheels and axles from the kit and the car can't weigh more than
8 oz. And that's it. This is a low key event, and I want this
to be a father-daughter project, so I don't want to go overboard.

What I have in mind is minimizing friction through judicious
alignment and smoothing and lubrication. Any suggestions
on how to accomplish this? What sort of lubricant should I
use?

Thanks for any and all ideas.

John Blinka

On Wed, 25 Jan 2006 23:04:47 GMT, John Blinka
wrote:

Hi,

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...

Any thoughts on how to build a fast car are welcome,
but I'm mostly interested in hearing ideas about how to prepare
the wheels and axles. The kit we have to use contains 2
steel axles of about 1/8" in diameter and four plastic wheels
whose hubs are a loose fit on the axles. Interference with
the body of the car prevents the wheel from moving axially toward
the car centerline. A plastic snap ring fitting in a groove at the
outboard end of the axle prevents the wheel from falling off
in the other direction.

Rules are nebulous. I think we're expected to use the
wheels and axles from the kit and the car can't weigh more than
8 oz. And that's it. This is a low key event, and I want this
to be a father-daughter project, so I don't want to go overboard.

What I have in mind is minimizing friction through judicious
alignment and smoothing and lubrication. Any suggestions
on how to accomplish this? What sort of lubricant should I
use?

Thanks for any and all ideas.

John Blinka
Here's what I did: On the night of the big race the car still has to
be weighted. 1/4" dia lead fishing weight works well. I did not want
my son drilling the holes as the drill could pass completely through
the car and into his hand. Instead, I drilled the holes and was the
one getting the wound cleaned and stitched up. Save your child from
this outcome and let your brother drill any holes so you can watch the
race with your child.
ERS

Polish axles, and make sure there is no stamnping or press marks
evident (like the marks around the head of a nail from
forming)...Ensure your wheels are in alignment, as alignment is a big
drag and every little bit helps.....Get the weight dead on the max.
Even if you have to buy another kit, make sure wheels rotate freely
but not wobbly. PTFE is the lube I would go with.
True up the wheels cirucmference and eliminate any mold flash
etc.round is much more efficient than egg shape when it comes to
wheels...You can possibly machine a V shape to the wheels profile so
the tread is the point of the V, which will eliminate even more
frictional loss.....

Sounds like a lot has changed since I fooled with them..5 oz was max,
and they used sheet rock "blue" nails for axles. I have a few kits up
in the attic form years gone by, one is circa late 50's early 60's and
one is from the 80's and another the early 90's........The later 90's
has rounded head pins for axles.....I used to use stainless steel
rivets with the wheels bored and trued to fit for my youngins axle. He
was doing fine in all the heats, but then kids being what kids are he
and a few others had to start pushing them on the concrete floor etc,
so much for trued V shaped wheels, but he still did fairly well....

On Wed, 25 Jan 2006 23:04:47 GMT, John Blinka
wrote:
Hi,

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...

Any thoughts on how to build a fast car are welcome,
but I'm mostly interested in hearing ideas about how to prepare
the wheels and axles. The kit we have to use contains 2
steel axles of about 1/8" in diameter and four plastic wheels
whose hubs are a loose fit on the axles. Interference with
the body of the car prevents the wheel from moving axially toward
the car centerline. A plastic snap ring fitting in a groove at the
outboard end of the axle prevents the wheel from falling off
in the other direction.

Rules are nebulous. I think we're expected to use the
wheels and axles from the kit and the car can't weigh more than
8 oz. And that's it. This is a low key event, and I want this
to be a father-daughter project, so I don't want to go overboard.

What I have in mind is minimizing friction through judicious
alignment and smoothing and lubrication. Any suggestions
on how to accomplish this? What sort of lubricant should I
use?

Thanks for any and all ideas.

John Blinka

--
\\\|///
( @ @ )
-----------oOOo(_)oOOo---------------


oooO
---------( )----Oooo----------------
\ ( ( )
\_) ) /
(_/
The original frugal ponder ! Koi-ahoi mates....

John Blinka wrote:
Hi,

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...

Any thoughts on how to build a fast car are welcome,
but I'm mostly interested in hearing ideas about how to prepare
the wheels and axles. The kit we have to use contains 2
steel axles of about 1/8" in diameter and four plastic wheels
whose hubs are a loose fit on the axles. Interference with
the body of the car prevents the wheel from moving axially toward
the car centerline. A plastic snap ring fitting in a groove at the
outboard end of the axle prevents the wheel from falling off
in the other direction.

Rules are nebulous. I think we're expected to use the
wheels and axles from the kit and the car can't weigh more than
8 oz. And that's it. This is a low key event, and I want this
to be a father-daughter project, so I don't want to go overboard.

What I have in mind is minimizing friction through judicious
alignment and smoothing and lubrication. Any suggestions
on how to accomplish this? What sort of lubricant should I
use?

Thanks for any and all ideas.

John Blinka

I just got finished helping my son do his Boy Scouts pinewood derby car.
From helping other dads over the years I can tell you that the previous
posts were right on the money. If you can, true the wheels. I pushed the
wheel on a .099 gage pin and took very light skim cuts in the Hardinge
to true the OD to the center hole. There are ridges on the nails from
the cold heading process on both the diameter and most importantly under
the head (like a parting line). I skim cut these off with a thin bit in
the Hardinge to clean up the ridges and parting line and then polished
the OD of the nails where the wheels will contact. I don't use the saw
slots for the nails. Instead I predrill .078 diameter holes for the
nails in the Bridgeport to insure absolute perfect alignment. Do drill
up to high or the car won't clear the 1/4" high track guide. The best
lube is spray on Teflon. Do the nails and wheels but tape the ends of
the nails so they won’t slip out of the car when you drive them in.
Lastly, add enough weight (anywhere) so you are right at the limit. For
the Boy Scouts that’s 5 ounces.

Is this a sanctioned event? Pinewood derby (Cub Scouts) use 5 oz weight.
Need max weight by adding lead. Verify on Postal scales. Suggest Max weight
and take a little cordless drill to take weight off if necessary (will help
others do the same) Car should be slightly rear bias on weight. Axles on
pine derby cars have two rough edges that need careful deburring and
polishing. Wheels need as much space apart as possible to prevent scrubbing
the guide rail. True wheels seem to work as good as regular wheels as they
wobble so bad. Rules won't allow wheel bushings or oversize pins.

Rules require dry lubricant. Most use dry graphite to lube the axle. Take
extra. The little ones will try to run the wheels off of it, this will screw
up the alignment. Need to roll straight.

Most have adult and Jr. division as well as outlaw (no rules). Some are
judge in different categories. Best of show, most original, fastest,
prettiest, whatever.
When we did it we made sure everyone won a certificate identifying their car
as special in some category.

Hard to have fun when your trying too hard. Keep in mind wins are usually in
just inches but having fun is priceless.

Easiest car to fab and polish would look like half a football. Kinda like
the cars they used on the salt flats made out of a aircraft fuel tank except
cut in half.

John Blinka wrote:

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...
snip

Sorry, I can't help you with your predicament, but you might like
this story:

http://www.geocities.com/~pack215/th...ofvictory.html

Not that I think you're like the father in that article, just that I
enjoyed reading it and it's related to the topic.

Good luck!

R,
Tom Q.

--
Remove bogusinfo to reply.

Rex B wrote:

You, a master builder with a 100% win record, ask US for advise?? G

Preferred lubricant seems to be dry PTFE powder.
Micropolish the axles.
I'd balance the car weight so all wheels carry the same weight.
No other suggestions.


I'd take a different approach...

Rig only two wheels in contact - opposite front and back.

Less drag is less drag, you know...

Richard

Narrowing the tire tread to a V has three benefits:
1.) Lowers the moment of inertial of the wheels, so the accelerate faster.
2.) Cuts air resistance of the wheel.
3.) Lowers rolling resistance.

You've heard most of the tricks already. The only one I'd add would be
to keep the weight to the back. Since the cars start on a slope and
end on the flat, there's more drop at the rear.

Streamlining should be a plus, but I've seen some real clunkers win.

And whatever you do, remember that your daughter is the boss. The
father of one of my older son's friends insisted that the weight would
be best taped underneath the car (flat piece of sheet lead). The son
thought that it might drag on the center strip. When the race started
and the car wouldn't move, you can imagine how both of them felt.

Whatever happened to powdered graphite?

John Martin

I was actually disqualified from my Cub Scout pinewood derby competition in
1966-ish. I beat everybody and then they DQ'd me for doing the mods
suggested by others in this thread. I put each wheel on a nail, spun it up
in an electric drill, and then held each wheel against sandpaper to smooth
them and get to the edge to a V shape. I used emery cloth to smooth the
nails. I cut down the nail heads. I smoothed and pointed the wood axle
ends so that when the wheels touched them, the friction was reduced, and I
fitted the wheels carefully so that there was little wobbling. I did it all
by myself, and there was nothing in the rules to prohibit what I did, and I
got DQ'd anyway. The *******s! I quit Cub Scouts shortly after that. Who
knows how many thousands of dollars I've spent on counseling to rid myself
of this trauma? And these lessons in creative rules interpretation
followed me and guided me through a successful amateur road racing career!

Anyhow, all those mods helped, and I'd recommend the modern equivalent of
them all. Powdered graphite was the hot setup friction reducer in my day.
Weight and aero are obvious.

I've wondered where the weight should be centered. Obviously you'd want to
reduce instability and have the car run a straight line down the track. If
the weight was in the center the car would be less impacted by rubbing
against the side or center rail, but might be less stable. Hmmmm...

Peter
"John Blinka" wrote in message
. ..
Hi,

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...

Any thoughts on how to build a fast car are welcome,
but I'm mostly interested in hearing ideas about how to prepare
the wheels and axles. The kit we have to use contains 2
steel axles of about 1/8" in diameter and four plastic wheels
whose hubs are a loose fit on the axles. Interference with
the body of the car prevents the wheel from moving axially toward
the car centerline. A plastic snap ring fitting in a groove at the
outboard end of the axle prevents the wheel from falling off
in the other direction.

Rules are nebulous. I think we're expected to use the
wheels and axles from the kit and the car can't weigh more than
8 oz. And that's it. This is a low key event, and I want this
to be a father-daughter project, so I don't want to go overboard.

What I have in mind is minimizing friction through judicious
alignment and smoothing and lubrication. Any suggestions
on how to accomplish this? What sort of lubricant should I
use?

Thanks for any and all ideas.

John Blinka

On Wed, 25 Jan 2006 23:04:47 GMT, John Blinka
wrote:

Any thoughts on how to build a fast car are welcome,

On-board webcam
http://www.spreadshirtmedia.com/webl...ood_derby.html

"John Martin" wrote in message
oups.com...

Streamlining should be a plus, but I've seen some real clunkers win.


After many Pinewood Derbies, my take is this:

It is just up to the pieces you get.

If you would take 1,000 Pinewood Derby kits, and ONLY put on the axles and
wheels, there would be a tremendous variance in the times.

This is due to the manufacturing variations in the wheels and axles.
(actually nails) There is a lot of slop in these items, and a fast car is
usually no more than a lucky combination of nails and pieces of plastic.

All the rest is just mental masturbation and ego meant to entertain 8 year
olds. And the dads bent on revenge for their losses.

Steve, an ex assistant Cubmaster, Den Leader, and FOS regional director.

Leo Lichtman wrote:
Narrowing the tire tread to a V has three benefits:
1.) Lowers the moment of inertial of the wheels, so the accelerate faster.
2.) Cuts air resistance of the wheel.
3.) Lowers rolling resistance.


Technically, we cannot make this type of modification. A little truing
up we can get away with but major changes like this to the wheels are
expressly prohibited in the rules included with the kit. Besides:
According to the experts air resistance has been discounted as
irrelevant at these speeds . I don't buy into the lower rolling
resistance theory. The only one I'm buying is the rotational inertia
effect but I'm going to double check with the expert (chief engineer).

John Martin wrote:
You've heard most of the tricks already. The only one I'd add would be
to keep the weight to the back. Since the cars start on a slope and
end on the flat, there's more drop at the rear.
Good point, that's makes a lot of sense.

Streamlining should be a plus, but I've seen some real clunkers win.
Apparently, according to the experts, the speeds are to low to make an
difference.

And whatever you do, remember that your daughter is the boss. The
father of one of my older son's friends insisted that the weight would
be best taped underneath the car (flat piece of sheet lead). The son
thought that it might drag on the center strip. When the race started
and the car wouldn't move, you can imagine how both of them felt.

Whatever happened to powdered graphite?
It got replaced by Teflon. Sometimes newer is actually better.

John Martin

Keep the weight in the back....it will fall longer....it has been debated
forever...trust me....the longer the majority of the weight is falling, the
faster the car goes. Center of balance should be about 1" in front of the
rear axel...further back, and the front wheels move around too much.

Polish the axels.....to a mirror finish.

Some sites to look at....

http://goaskgrandpa.com/sample01.htm

http://pinewoodfreak.com/2006/01/04/...es-and-wheels/

http://www.three-peaks.net/pinecar.htm


"John Blinka" wrote in message
. ..
Hi,

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...

Any thoughts on how to build a fast car are welcome,
but I'm mostly interested in hearing ideas about how to prepare
the wheels and axles. The kit we have to use contains 2
steel axles of about 1/8" in diameter and four plastic wheels
whose hubs are a loose fit on the axles. Interference with
the body of the car prevents the wheel from moving axially toward
the car centerline. A plastic snap ring fitting in a groove at the
outboard end of the axle prevents the wheel from falling off
in the other direction.

Rules are nebulous. I think we're expected to use the
wheels and axles from the kit and the car can't weigh more than
8 oz. And that's it. This is a low key event, and I want this
to be a father-daughter project, so I don't want to go overboard.

What I have in mind is minimizing friction through judicious
alignment and smoothing and lubrication. Any suggestions
on how to accomplish this? What sort of lubricant should I
use?

Thanks for any and all ideas.

John Blinka

This takes me back a few decades.
I remember a fellow at the lab who turned the axel rods (nails) on a
microlathe, deposited lubricant on them, and then drove them in crooked, and
wasted it all.

First suggestion. Do not do anything that you cannot do with your child.
That is the entire purpose. Having a winning car and alienating your child
is the wrong thing to do.
Work with him/her.
If this is the introduction to machine tools, make it a positive
introduction. IF you cannot describe why you are doing something to the
child, then it should not be done.

The design [color, pattern, coolness] is much more important than the
mechanics. This is their design. Let them do it, and you just help them.

Remember this is a kids project. Have your own fathers section if you must,
but let the kids learn and have fun
Bert

"John Blinka" wrote in message
. ..
Hi,

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...
SNIP

Thank you for the great story. I can relate, having been raised by a
working mom.

James

On Wed, 25 Jan 2006 20:00:41 -0500, Tom Quackenbush
wrote:

John Blinka wrote:

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...
snip

Sorry, I can't help you with your predicament, but you might like
this story:

http://www.geocities.com/~pack215/th...ofvictory.html

Not that I think you're like the father in that article, just that I
enjoyed reading it and it's related to the topic.

Good luck!

R,
Tom Q.

On Wed, 25 Jan 2006 23:04:47 GMT, John Blinka
wrote:

Hi,

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...


Let your kid build the car. Any work you do is robbing her af a fun
experience. And any cheating robs all the other kids.

Our Cub Scout pack got so out of control with dad-built cars that we
added a seperate class for them. It was sad- some of the boys couldn't
pick their own car out of a line up- they had never seen it until race
day.

And for all those theories as to why one car wins and another doesn't-
they are all bull****. When we rebuilt our 5 lane track (and added a
high speed finish line clock), we tested it with a variety of cars,
running each car through each lane 5 times. After 25 runs, none of the
cars was a consistant winner, nor did any lane come up faster or
slower than the others.

There is one tip- build the car a little heavy (the limit is 5 oz) in
case the official scale is off a little- it's easy to take weight off.

-Carl

Leo Lichtman wrote:


Narrowing the tire tread to a V has three benefits:
1.) Lowers the moment of inertial of the wheels, so the accelerate faster.

Maybe. A few decimals down...

2.) Cuts air resistance of the wheel.

At these speeds air resistance is a small part of it.

3.) Lowers rolling resistance.

I think this is the one that matters.

However you can get away with it...


Richard

Carl Byrns wrote in article
...


Let your kid build the car. Any work you do is robbing her af a fun
experience. And any cheating robs all the other kids.


AMEN!!!!!!!

"John Blinka" wrote in message
. ..
Rules are nebulous. I think we're expected to use the
wheels and axles from the kit and the car can't weigh more than
8 oz. And that's it. This is a low key event, and I want this
to be a father-daughter project, so I don't want to go overboard.

What I have in mind is minimizing friction through judicious
alignment and smoothing and lubrication.

I think you'll find the pinewood rules limit the all-up weight to 5oz. I
know that used to be the limit.

One thing I noticed about the winners back when I was the Cubs district
chairman here was that they all had nearly flat wheel profiles... that is,
the part touching the track was flat all the way across, rather than
crowned. I even tested those two alternatives, and flat seems a bit faster.

My theory is that a crowned wheel tends to "fall into the cracks"...
actually the grain, on the plywood tracks, while a flat profile runs over
the tops of the cracks.

The other thing I noticed was that all the winning cars were VERY
low-profile, and well balanced among all four wheels. The odds-on favorite
in every heat was the car that was 'flat' vertically.

One kid came in with a car he 'built' with his dad's help. It was a mere
sliver of the original wood glued to a flat sheet of lead roof flashing.
The whole body was about 1/8" thick! It won every heat, and the over-all.

LLoyd

Lloyd E. Sponenburgh wrote in article
...

"John Blinka" wrote in message
. ..
Rules are nebulous. I think we're expected to use the
wheels and axles from the kit and the car can't weigh more than
8 oz. And that's it. This is a low key event, and I want this
to be a father-daughter project, so I don't want to go overboard.

What I have in mind is minimizing friction through judicious
alignment and smoothing and lubrication.

I think you'll find the pinewood rules limit the all-up weight to 5oz. I

know that used to be the limit.

One thing I noticed about the winners back when I was the Cubs district
chairman here was that they all had nearly flat wheel profiles... that
is,
the part touching the track was flat all the way across, rather than
crowned. I even tested those two alternatives, and flat seems a bit
faster.

My theory is that a crowned wheel tends to "fall into the cracks"...
actually the grain, on the plywood tracks, while a flat profile runs over

the tops of the cracks.



I would suspect that the flatter wheels with a more-stabilizing footprint
ran more true vertical - keeping them from flopping around in their loose
fit on the axles.....

Whatever happened to powdered graphite?

It's still there.
American Grease Stick (AGS)
Part No. MZ-2

FYAAA - for your amazement and amusement -

http://www.abc-pinewood-derby.com/pi...erby_rules.htm

Following are the inspection points

1. The car weight shall not exceed 5.0 ounces. The official race scale shall
be considered final.
2. The overall length of the car shall not exceed 7 inches.
3. The overall width of the car shall not exceed 2 ¾ inches.
4. The car must have 1 ¾" clearance between the wheels.
5. The car must have 3/8" clearance underneath the body.
6. The wood provided in the kit must be used. The block may be shaped any
way that is desired.
7. The wheels supplied with the kit must be used. The wheels may not be cut,
drilled, beveled or rounded. You may remove the seam from the wheels.
8. The axles supplied with the kit must be used. They may be polished or
lubricated.
9. Wheel bearings, washers or bushings are prohibited.
10. The car must not ride on any type of springs.
11. The car must be freewheeling, with no starting devices.
12. No loose material of any kind, such as lead shot, may be used.

Each car must pass inspection by the official inspection committee before it
will be allowed to compete. The Inspection Committee has the responsibility
to disqualify those cars that do not meet these specifications.

(end of cite)

WHEN IN DOUBT, RTFM!

We have been getting all manner of advice on the subject of Pinewood Derby
cars, some of it totally erroneous.

Individual groups are allowed to have their own ADDITIONAL rules. They may
create additional classes for cars that have special characteristics
prohibited by the rules, such as modified axles, bearings, modified wheels,
wheels different than those provided in the kit, suspension systems ........
anything. But those cars are not considered a part of the actual CSA
sanctioned event, and are only for entertainment purposes and bragging
rights.

If in doubt, reading the instructions is a good place to start. Googling
also works.

Steve

The Tagge's wrote:

This takes me back a few decades.
I remember a fellow at the lab who turned the axel rods (nails) on a
microlathe, deposited lubricant on them, and then drove them in crooked, and
wasted it all.

First suggestion. Do not do anything that you cannot do with your child.
That is the entire purpose. Having a winning car and alienating your child
is the wrong thing to do.
Work with him/her.
If this is the introduction to machine tools, make it a positive
introduction. IF you cannot describe why you are doing something to the
child, then it should not be done.

The design [color, pattern, coolness] is much more important than the
mechanics. This is their design. Let them do it, and you just help them.

Remember this is a kids project. Have your own fathers section if you must,
but let the kids learn and have fun
Bert

"John Blinka" wrote in message
...




Good advice!!
My cars always took first in our Scout pack and went to the regionals
but they were built in a high tech engineering lab so I don't really
have a clue what was so special about them :-)

I googled "pinewood derby car" and got 56,000 hits. Maybe having your
daughter do some internet research with that list as a start would do
double duty for her---
We went through a lot of this when our kids were young. Made parts
in the machine shops at work, had design meetings on the subject, etc..
One year, when we got to the race, the "official" scale was 'way off
so not much mattered.
My couple of tips:
-wieght is everything. Consider getting the car close to weight ahead
of time but leave a 3/8" diameter hole someplace with a tapped plug so
you can add enough buckshot at weigh-in to max the car out.
-The wheels are (at least they used to be) brittle. A friend worked
pretty hard with his son, but the boy set the car down on a steel
folding chair and it rolled right off and onto the floor. Broke a wheel
before the contest ever started.

Pete Stanaitis
---------------------

John Blinka wrote:
Hi,

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...

Any thoughts on how to build a fast car are welcome,
but I'm mostly interested in hearing ideas about how to prepare
the wheels and axles. The kit we have to use contains 2
steel axles of about 1/8" in diameter and four plastic wheels
whose hubs are a loose fit on the axles. Interference with
the body of the car prevents the wheel from moving axially toward
the car centerline. A plastic snap ring fitting in a groove at the
outboard end of the axle prevents the wheel from falling off
in the other direction.

Rules are nebulous. I think we're expected to use the
wheels and axles from the kit and the car can't weigh more than
8 oz. And that's it. This is a low key event, and I want this
to be a father-daughter project, so I don't want to go overboard.

What I have in mind is minimizing friction through judicious
alignment and smoothing and lubrication. Any suggestions
on how to accomplish this? What sort of lubricant should I
use?

Thanks for any and all ideas.

John Blinka

There was another Thread on pinewoods a while back, but it may have been
on another group. The subject of weighting the wheels was discussed
extensively, lots of theory and techniques for getting the weight in the
wheels. It doesn't appear to be a violation of the rules. I did this
myself sometime in the early 70's. What we did to avoid too much parent
take over of the kids project, was to have a parent division so the
parents could build their own cars, and spend less time building one for
the kid. It worked reasonably well. As to the effectiveness of
weighting the wheels; it worked great if the track was long enough. The
weighted wheels were slow to start, but in the level part of the track,
they would overtake the other cars if the track was long enough. As I
recall, we had two different tracks and one was a little longer. We also
had a separate competition for the best looking creation. Great fun.
--
Billy Hiebert
HIEBERT SCULPTURE WORKS
Small Part Injection Molding
http://www.hieberts.com

Steve B wrote:
FYAAA - for your amazement and amusement -

http://www.abc-pinewood-derby.com/pi...erby_rules.htm

Following are the inspection points

1. The car weight shall not exceed 5.0 ounces. The official race scale shall
be considered final.
2. The overall length of the car shall not exceed 7 inches.
3. The overall width of the car shall not exceed 2 ¾ inches.
4. The car must have 1 ¾" clearance between the wheels.
5. The car must have 3/8" clearance underneath the body.
6. The wood provided in the kit must be used. The block may be shaped any
way that is desired.
7. The wheels supplied with the kit must be used. The wheels may not be cut,
drilled, beveled or rounded. You may remove the seam from the wheels.
8. The axles supplied with the kit must be used. They may be polished or
lubricated.
9. Wheel bearings, washers or bushings are prohibited.
10. The car must not ride on any type of springs.
11. The car must be freewheeling, with no starting devices.
12. No loose material of any kind, such as lead shot, may be used.

Each car must pass inspection by the official inspection committee before it
will be allowed to compete. The Inspection Committee has the responsibility
to disqualify those cars that do not meet these specifications.

(end of cite)

WHEN IN DOUBT, RTFM!

We have been getting all manner of advice on the subject of Pinewood Derby
cars, some of it totally erroneous.

Individual groups are allowed to have their own ADDITIONAL rules. They may
create additional classes for cars that have special characteristics
prohibited by the rules, such as modified axles, bearings, modified wheels,
wheels different than those provided in the kit, suspension systems ........
anything. But those cars are not considered a part of the actual CSA
sanctioned event, and are only for entertainment purposes and bragging
rights.

If in doubt, reading the instructions is a good place to start. Googling
also works.

Steve

In article , John Blinka says...

Any thoughts on how to build a fast car are welcome,

There's a huge variation in the wheels that are delivered.

Buy a few kits and choose the best running one, the most concentric
ones.

Then build a car where only three of the wheels actually
touch the track. Two rears, and a front.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

The *best* pinewood derby advice I can give other than the suggestiins
he

Lobby for an outlaw/unlimited/parents class to keep the kids race fun!

I think there should be a class for "best cheat" myself.

Dave

More money than time? Check out this auction....

http://cgi.ebay.com/High-Performance...cmdZV iewItem

It's a private auction, too.

On 26 Jan 2006 09:22:02 -0800, jim rozen
wrote:

In article , John Blinka says...

Any thoughts on how to build a fast car are welcome,

There's a huge variation in the wheels that are delivered.

Buy a few kits and choose the best running one, the most concentric
ones.

Then build a car where only three of the wheels actually
touch the track. Two rears, and a front.

Jim

The rules state all four wheels have to support the car.

-Carl

Rex B wrote:
Preferred lubricant seems to be dry PTFE powder.

Looks like MSC sells aerosol cans of this stuff. That's what
I'll get.

Micropolish the axles.

I've never polished anything. What sort of abrasives are appropriate?

I'd balance the car weight so all wheels carry the same weight.

That makes sense, but might be hard in practice. You'd need a pretty
flat surface and some way of weighing corners to some small fraction
of an ounce. Maybe you could get at the same result indirectly by
taking some practice runs, seeing if the car runs straight, and adjusting
the "suspension" somehow until it does run straight.

John

K. A. Cannon wrote:

If you really want to be a smart ass get some brass tubes, some steel
balls slightly smaller than the tubes. Seal one end of the tube, put
in the balls and then fill with oil, seal the other end of the tube.
Now you have a movable weight system that won't rattle. Mount that
assembly at an angle in the car...low point toward the front.
This works great...but is considered a cheat in most scout troops.

That idea appeals to my excess of engineering education. I was wondering
how to gain a little extra in the distance through which the cg drops.
Wouldn't you have to invert the car before setting it on the track so the
balls are at the top at the start? And wouldn't you have to size the
balls so that they dropped in the tube in the time it takes for the
car to run the race?

John

Tom Quackenbush wrote:

Sorry, I can't help you with your predicament, but you might like
this story:

http://www.geocities.com/~pack215/th...ofvictory.html

Not that I think you're like the father in that article, just that I
enjoyed reading it and it's related to the topic.

Thanks, that was a good read. In my cub scout days we raced
balsa wood rockets that were suspended from a long horizontal
wire and were powered by rubber band driven propellers. The
rules stipulated one rubber band, and the racer had to build the
thing himself. A lot of perfectly built rockets with a lot more
rubber bands showed up and I finished dead last. It's fun to think about
all the things one could do to make a pinewood derby car go
fast, but my daughter and I are racing against my friends and their
daughters. I don't want to be "one of those dads" to them.

John

In article ,
tomcas wrote:
:
:I just got finished helping my son do his Boy Scouts pinewood derby car.
: From helping other dads over the years I can tell you that the previous
osts were right on the money. If you can, true the wheels. I pushed the
:wheel on a .099 gage pin and took very light skim cuts in the Hardinge
:to true the OD to the center hole. There are ridges on the nails from
:the cold heading process on both the diameter and most importantly under
:the head (like a parting line). I skim cut these off with a thin bit in
:the Hardinge to clean up the ridges and parting line and then polished
:the OD of the nails where the wheels will contact. I don't use the saw
:slots for the nails. Instead I predrill .078 diameter holes for the
:nails in the Bridgeport to insure absolute perfect alignment. Do drill
:up to high or the car won't clear the 1/4" high track guide. The best
:lube is spray on Teflon. Do the nails and wheels but tape the ends of
:the nails so they won’t slip out of the car when you drive them in.
:Lastly, add enough weight (anywhere) so you are right at the limit. For
:the Boy Scouts that’s 5 ounces.

Add any weight near the back of the car so that the added weight starts
off higher on the ramp and gives a longer push. Shape the front of the
car so that it contacts the starting barrier as high up as possible (a
reverse wedge). The barrier rotates down to release the cars, so the
car with the highest contact point gets released first.

Furniture wax (Pledge(R), or similar) makes an excellent lubricant for
the wheels -- much better than Teflon(R). The Teflon would hold up
longer, but how many miles do you expect this thing to go?

--
Bob Nichols AT comcast.net I am "RNichols42"

Jim Newell wrote:


Some sites to look at....

http://goaskgrandpa.com/sample01.htm

http://pinewoodfreak.com/2006/01/04/...es-and-wheels/

http://www.three-peaks.net/pinecar.htm

Thanks for these references. I had googled but not seen these. The
goaskgrandpa site is technically intriguing. His argument seems to
be that a significant amount of energy is absorbed by the car bouncing
around. He's essentially made a 4 wheel independently sprung
suspension so that as little as possible of the car vibrates and absorbs
energy when it hits a bump. I've never seen these cars race, so I
hadn't realized they bounce so much.

John

The Tagge's wrote:

The design [color, pattern, coolness] is much more important than the
mechanics. This is their design. Let them do it, and you just help them.

This is the part that appeals to my daughter the most. I've always
wanted to do metal casting, and she likes to sculpt in clay, so we're
going to see if we can't make the ballast weight an interesting
shape. I'm inclined to get a piece of the low melting point fixturing
metal, melt it in hot water and pour it into a silicone rubber mold
we make from her sculpture.

John

In article , Carl Byrns says...

The rules state all four wheels have to support the car.

That may well be a local rule, the kit that my co-worker and
his kid just finished did not state that.

What do folks do to adhere to that, if they didn't have a
surface plate to set their car up with? g

All you need to do is get a few thou under one wheel.
Honestly it's nearly impossible to get them all turning,
on a surface plate. We tried.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

Eric R Snow wrote:
On Wed, 25 Jan 2006 23:04:47 GMT, John Blinka
wrote:


Hi,

I'm in a predicament: I helped a friend a few years ago with a
small detail on a pinewood derby car he was building with his
daughter, and he won the tournament with it! That was a fluke,
but now my kid wants to race, and you can guess what her
expectations are...

Any thoughts on how to build a fast car are welcome,
but I'm mostly interested in hearing ideas about how to prepare
the wheels and axles. The kit we have to use contains 2
steel axles of about 1/8" in diameter and four plastic wheels
whose hubs are a loose fit on the axles. Interference with
the body of the car prevents the wheel from moving axially toward
the car centerline. A plastic snap ring fitting in a groove at the
outboard end of the axle prevents the wheel from falling off
in the other direction.

Rules are nebulous. I think we're expected to use the
wheels and axles from the kit and the car can't weigh more than
8 oz. And that's it. This is a low key event, and I want this
to be a father-daughter project, so I don't want to go overboard.

What I have in mind is minimizing friction through judicious
alignment and smoothing and lubrication. Any suggestions
on how to accomplish this? What sort of lubricant should I
use?

Thanks for any and all ideas.

John Blinka

Here's what I did: On the night of the big race the car still has to
be weighted. 1/4" dia lead fishing weight works well. I did not want
my son drilling the holes as the drill could pass completely through
the car and into his hand. Instead, I drilled the holes and was the
one getting the wound cleaned and stitched up. Save your child from
this outcome and let your brother drill any holes so you can watch the
race with your child.
ERS

Most decent hobby shops have Woodland Scenics Pine Car parts.

They have several different shaped weights with snap off parts to just
screw to the bottom of the pine car.

Some places have a 5 Oz weight limit.

Whatever the limit is you want the car just under the limit.

Hugh