More Harm Than Good?

[CTDerbyDad]

When my son and I make a car for his annual Pinewood Derby, one of the first things we do is mark the wheels across the "tread" area and chuck them up in our drill press using a Derby Worx standard Wheel Mandrel. We gently wet sand them until all of the marks are gone. It appears each wheel is slightly out of round. Not only is this time consuming for him, but I was wondering if the threaded mandrel was possibly doing more harm than good. Do the league racers who don't buy pre-prepped wheels (not an option under our rules) do this step?

 

[bracketracer]

For our scout race I have the boys sort their wheels by the spin and the runout (the kids can't use lathed wheels). They don't use anything threaded in the bore though, too much chance for damage and I'm nervous that clamping a wheel by it's inner and outer hub could either crush it or burr it up.

 

[DerbyDad4Hire]

The runout using that method might be a bit worse. The only benefit is making them lite.

 

[Rebel Racer]

DD4H are you suggesting not to use a wheel mandrel at all?

 

[BulldogRacing]

The wheel mandrels that derby works sells is awful. Te run out on them is usually much worse then an out of the box wheel. If you want to chuck up a wheel do it on a pin gauge but understand your drill and drill presses will also have runout. If you are just doing this to polish a q-tip stock will mount the wheel up nice for you on a drill, all you need is a slight press fit by rotating the wheel on, don't just push it straight on.

 

[HurriCrane Racing]

The wheel mandrels that derby works sells is awful. Te run out on them is usually much worse then an out of the box wheel. If you want to chuck up a wheel do it on a pin gauge but understand your drill and drill presses will also have runout. If you are just doing this to polish a q-tip stock will mount the wheel up nice for you on a drill, all you need is a slight press fit by rotating the wheel on, don't just push it straight on.

Great advice Bulldog. I made a simple runout gauge using a dial gauge and a pin gauge.
It does the trick.

 

[Rebel Racer]

Great advice Bulldog. I made a simple runout gauge using a dial gauge and a pin gauge.
It does the trick.

Great advice Bulldog. I made a simple runout gauge using a dial gauge and a pin gauge.
It does the trick.