Search found 53 matches

by macd
Wed Feb 05, 2014 10:30 pm
Forum: General Coordinator Topics
Topic: Have you seen issues with fixed axle location rules?
Replies: 13
Views: 4384

Re: Have you seen issues with fixed axle location rules?

What are your rules?
Do they require, or imply the requirement, that every car be exactly 7 inches long?
by macd
Sat Jan 18, 2014 3:02 pm
Forum: General Topics
Topic: District Best Design-No Awards
Replies: 8
Views: 3056

Re: District Best Design-No Awards

Our district has two design awards: "Best Design" and "Most Unique".
The winners are chosen by volunteer judges.

Those at district will have won first place in that category at their pack race.

Those racing (competing for speed awards) are not eligible for design awards, and vice versa.
by macd
Mon Jan 13, 2014 4:06 pm
Forum: General Coordinator Topics
Topic: Question regarding wheel mod-eliminating round bump molds
Replies: 13
Views: 3577

Re: Question regarding wheel mod-eliminating round bump mold

The rule: "Wheels may be lightly sanded to remove mold projection" was probably violated if the wheel was sanded to the point that the little dots around the circumference (I think of them as faux tread) have been removed. My district and pack has the same rule. I believe it was written pre-2009 whe...
by macd
Sun Jan 12, 2014 2:42 pm
Forum: General Coordinator Topics
Topic: Registration tonight - suspect car / notched raised wheel
Replies: 12
Views: 3962

Re: Registration tonight - suspect car / notched raised whee

How much does the modified wheel weigh? I think it looks like an attempt to lighten the wheels.
The body looks like the Grand Prix from abc pinewood derby.
by macd
Mon Dec 30, 2013 8:05 pm
Forum: Car & Semi-Truck Construction
Topic: Help selecting straight BSA axles?
Replies: 4
Views: 1163

Re: Help selecting straight BSA axles?

Think about the extreme case: if you have an axle with a 45 degree bend, chuck it, and spin it you'll see a cone shape.
If you have a perfectly straight axle, chuck it, and spin it, you'll still see a "nail shape".

Look for axles with no cone.
by macd
Thu Jan 10, 2013 12:44 pm
Forum: Car & Semi-Truck Construction
Topic: Weights in a very thin car
Replies: 11
Views: 3734

Re: Weights in a very thin car

The design you pointed to specifies the location of the weights.
They've drawn 12 quarter-inch cubes behind the rear axle and 18 quarter-inch cubs in front the rear axle.
If you did that, the car would not pop a wheelie.
Are your rear axles as drawn on the design (one inch from the back)?
by macd
Wed Jan 09, 2013 1:54 pm
Forum: General Coordinator Topics
Topic: Axles in Revell Kits
Replies: 15
Views: 6279

Re: Axles in Revell Kits

rpcarpe wrote:and both Revell and the BSA original qualify as 'Official BSA' axles, right?
It depends on the rules from your Pack or District.
They would be illegal in our Pack and District races.
The Revell wheels and axels are "officially licensed". The scout shop versions are "official".
by macd
Mon Jan 07, 2013 11:58 am
Forum: Car & Semi-Truck Construction
Topic: Homemade Concentricity Gauge
Replies: 26
Views: 10812

Re: Homemade Concentricity Gauge

I'll share our results too. My son ran out of steam after testing just 18 from a big rig kit. We got a good set of four, and still have extra wheels to measure for next year. Of our 18, five had smaller bores (.0965), while the rest were .0970). Interestingly, the small bores were all #11 and #6 mol...
by macd
Wed Jan 02, 2013 8:00 am
Forum: Car & Semi-Truck Construction
Topic: Mold #s on the wheels?
Replies: 19
Views: 3366

Re: Mold #s on the wheels?

Our plan is to find the best set, and run them in modified. We will only polish and burnish the bore. I have low confidence that with our current tools and skill that we'll be able to improve a wheel. I do have a mandrel and a drill press, maybe we'ill practice on a few and measure our results. Shou...
by macd
Tue Jan 01, 2013 11:05 pm
Forum: Car & Semi-Truck Construction
Topic: Mold #s on the wheels?
Replies: 19
Views: 3366

Re: Mold #s on the wheels?

For this season, I've collected 48 wheels. I've built a concentricity gage per FS's directions at http://www.derbytalk.com/viewtopic.php?f=11&t=6655&hilit=concentricity#p63852 I just ordered a set of four gage pins: 0.0955 through 0.0970. What process should my son use to go through these wheels to ...
by macd
Sun Dec 09, 2012 11:20 pm
Forum: General Car/Truck Racer Topics
Topic: Using slots rule question
Replies: 17
Views: 3401

Re: Using slots rule question

What would I do? -- Drill my own axle holes. If you want to optimize speed, you would only drill your own axle holes if you think your can improve upon the slots. If you have a drill press or other tool that can make holes or slots that are "more square" than the pre-cut slots, then you have met bot...
by macd
Mon Dec 03, 2012 7:39 pm
Forum: General Coordinator Topics
Topic: Pinewood Derby Rules
Replies: 60
Views: 18576

Re: Pinewood Derby Rules

Our rules specify to use the "block from the kit". We allow replacement wheels, but only "from the scout store". These would both rule out the Revel kits. A Revel wheel (from a kit or tube) can be easily differentiated from a BSA wheel. Revel's are stamped "Made in China", and scout store wheels are...
by macd
Thu Nov 29, 2012 10:56 am
Forum: Car & Semi-Truck Construction
Topic: Sanding treads with mandrel and sanding block
Replies: 41
Views: 5781

Re: Sanding treads with mandrel and sanding block

I found some Big Rig kits on clearance at the scout store this year, so my son and I have a 36 wheels to sort through. Is picking out matching mold numbers (looking for the documented higher quality numbers) a close enough proxy to taking the measurements mentioned above? Does anyone have additional...
by macd
Tue Nov 20, 2012 7:54 pm
Forum: General Car/Truck Racer Topics
Topic: This years BSA wheels look like a regression
Replies: 9
Views: 2847

Re: This years BSA wheels look like a regression

We got our kits tonight. They are identical to last year's kits. The box is decorated like a present. Like last year, above the UPC symbol is written Item #17000. Our box from last year was stamped with "IN0911". I assume manufactured in September 2011. Our box from this year is stamped with "0812NI...
by macd
Wed Nov 07, 2012 2:34 pm
Forum: General Car/Truck Racer Topics
Topic: This years BSA wheels look like a regression
Replies: 9
Views: 2847

Re: This years BSA wheels look like a regression

Has anyone picked up a kit at the scout shop this year? Last year, tubes of wheels purchased at hobby shops were the Revell wheels, while tubes of wheels purchased at the scout shop were still the "good ones". I hope these new Revell kits stay in the hobby shops, and that the kits at the scout shop ...