Search found 76 matches

by davidwilkie
Sat Feb 06, 2016 11:14 am
Forum: Car & Semi-Truck Construction
Topic: How to secure DFW axle?
Replies: 16
Views: 22895

How to secure DFW axle?

Any tips on how to secure the DFW axle (or any axle for that matter) so it doesn't move from the rough handling that always occurs during handling by the race volunteers? My son had a car set for a 2" left drift over 4' (DFW is on the right) and after it performed relatively poorly, after racin...
by davidwilkie
Fri Feb 05, 2016 12:16 pm
Forum: General Car/Truck Racer Topics
Topic: Re-prep wheels or axles a year later?
Replies: 4
Views: 8027

Re: Re-prep wheels or axles a year later?

Nope, no times, only that it was a winner last year. Is 0.02 slower very much? Not sure if you're say "wow, it's almost as fast as the new car!" or "wow, the new car is much faster." Which do you mean? I've pulled the axles and looked into the wheel bores. They don't look slick a...
by davidwilkie
Fri Feb 05, 2016 12:44 am
Forum: General Car/Truck Racer Topics
Topic: Re-prep wheels or axles a year later?
Replies: 4
Views: 8027

Re-prep wheels or axles a year later?

For a winning car a year ago, any reason to re-prep the axles and/or hubs a year later (beyond just re-lubing)? The nail heads show some oxidation, but the axles themselves look pretty clean. For a non-Scout race, would certainly would prefer to save the work and just re-lube and go, plus the anxiet...
by davidwilkie
Sun Jan 24, 2016 9:27 am
Forum: Car & Semi-Truck Construction
Topic: Grooves in wheel bores?
Replies: 10
Views: 10219

Grooves in wheel bores?

I was searching for something and came across this:... http://hubpages.com/sports/WinningAPinewoodDerby http://usercontent1.hubimg.com/4514940_f260.jpg ...which suggests putting grooves in the wheel bores to retain graphite. Goes against all the polishing strategies my boys have ever done and so I w...
by davidwilkie
Wed Feb 04, 2015 10:15 pm
Forum: General Car/Truck Racer Topics
Topic: Burnish the "outside" of wheels with graphite too?
Replies: 3
Views: 5995

Burnish the "outside" of wheels with graphite too?

I seem to recall reading about people applying graphite to the outside tread (that contacts the track) with graphite. Do I have that correct? I always thought the outer tread should be as clean as possible, even using alcohol to clean?
by davidwilkie
Wed Feb 04, 2015 8:13 pm
Forum: Car & Semi-Truck Construction
Topic: Please critique this Axle and Bore prep processes
Replies: 10
Views: 10460

Please critique this Axle and Bore prep processes

Would appreciate any critique of the axle and bore prep my sons have planned for their cars. Here it goes: Axles: 1.Remove burs with nail file. Dremel turned off for this step. On for others. 2. Starting at grit 600, wet sand with strips (only about 5 seconds each for Dremel on high speed) including...
by davidwilkie
Tue Feb 03, 2015 12:11 pm
Forum: General Car/Truck Racer Topics
Topic: Anyone having success with Pledge?
Replies: 5
Views: 9615

Re: Anyone having success with Pledge?

Our rules just say dry at race time. Nothing about dry or graphite only.
by davidwilkie
Tue Feb 03, 2015 8:31 am
Forum: General Car/Truck Racer Topics
Topic: Anyone having success with Pledge?
Replies: 5
Views: 9615

Anyone having success with Pledge?

I've read about using it on axles after polishing by spraying it on, letting it dry and then wiping off, so that it's totally dry, and then putting the wheels on. I also wonder if burnishing the axles with graphite should be done or not, and if so, before or after the pledge?
by davidwilkie
Mon Feb 02, 2015 9:25 pm
Forum: Car & Semi-Truck Construction
Topic: Geetting COM Under 1/2" ???
Replies: 35
Views: 31780

Re: Geetting COM Under 1/2" ???

what / where do you mean by "photos section" ?
by davidwilkie
Mon Feb 02, 2015 1:21 pm
Forum: Car & Semi-Truck Construction
Topic: Tungsten Puma Weighta
Replies: 46
Views: 44840

Re: Tungsten Puma Weighta

I have another post related to this ( http://www.derbytalk.com/viewtopic.php?f=11&t=7909&p=76153#p76153 ) but in case you are wondering, here is a picture of my son's car with puma weights on it and the COM can be set under 0.5 inches if we so want it to, which is less than the radius of the...
by davidwilkie
Mon Feb 02, 2015 1:07 pm
Forum: Car & Semi-Truck Construction
Topic: Crazy to go to under 0.5 inches COM?
Replies: 11
Views: 10607

Re: Crazy to go to under 0.5 inches COM?

I measured how much weight would be on the DFW. Since we can move the 3 weights we still need to place into any of the pockets forward of the rear axle, we could adjust the COM / weight on DFW. Since the COM is less than the diameter of the puma weights, I thought I'd show the weight on the DFW for ...
by davidwilkie
Sun Feb 01, 2015 2:39 pm
Forum: Car & Semi-Truck Construction
Topic: Crazy to go to under 0.5 inches COM?
Replies: 11
Views: 10607

Crazy to go to under 0.5 inches COM?

with puma weights we could end up with a COM at or even less than 1/2" we need to add 3 more tungsten cubes to hit 5 oz ... if we put them near the axle then the COM will be inside the diameter of the puma weights themselves (making it hard to measure)...or we could slide them forward and have ...
by davidwilkie
Sat Jan 31, 2015 5:42 am
Forum: General Car/Truck Racer Topics
Topic: weight, anyone doing the new placement ?
Replies: 53
Views: 44945

Re: weight, anyone doing the new placement ?

There's a lot of opportunity for torsion-based tear-out with a drill, that could destroy your work in the latter stages of drilling the final few holes. Scrollsawer. We were thinking drill the holes before cutting the body thin, so that we wouldn't have to drill the holes all the way through (which...
by davidwilkie
Sat Jan 31, 2015 5:26 am
Forum: Car & Semi-Truck Construction
Topic: With Puma weights should rest of tungsten be behind axle?
Replies: 2
Views: 4661

With Puma weights should rest of tungsten be behind axle?

My boys wanted to try something new this year so we are going with the Puma weights http://www.derbymonkeygarage.com/v/vspfiles/photos/7979-2.jpg http://www.derbymonkeygarage.com/mobile/Product.aspx?id=37977 If we want a low COM car (5/8" or less) given the puma weights are at the axle, is it l...
by davidwilkie
Fri Jan 30, 2015 6:52 pm
Forum: Car & Semi-Truck Construction
Topic: Stock wheelbase...best to shift axles back?
Replies: 15
Views: 17965

Re: Stock wheelbase...best to shift axles back?

http://5kidsracing.webs.com/L2.PNG This may help, it depicts 1/4" cubes in the weight pocket. This isn't at 4.5" WB but just set your axle line at 5/8 from the back and go from there. I usually shade everything a hair away from the end to make sure the back weights don't end up sticking o...