Sanding the Wheels

[Cabrzama]

It's one week to race day. My son sanded the wheels a little with 400 grit, but I can't help but wonder if it was enough. You can still see a visible burr (tiny hole), but it feels smooth to touch--even across the burr. He hand-sanded each for about 2-3 minutes. Was that enough? How do we do it just right?

[Splinter Sprinter]

That’s a great question and in a timely manner. Maximum Velocity just sent out an e-mail announcing a new tool to help with wheel tread.

I’m new to this forum and don’t 100% fully know its policy regarding talking about or pitching an active member’s product so I’ll leave it at that. Just go to the web site.

You also mentioned that your son spent 3-4 minuets trying to sand down the mold gate “a visible burr (tiny hole)”. I’m not sure of the processes he was using, but he may want to be careful not to concentrate and sand on that little mold gate too much, as he might create a flat spot if the wheel isn’t turning on a rotary tool or lathe. Good Luck to you and your son.

Which brings a question to mind, Does anyone??? know if you can you use the Pro-Wheel Shaver with a rotary tool? Hint Hint Hint!

[Darin McGrew]

Does anyone??? know if you can you use the Pro-Wheel Shaver with a rotary tool?

IIRC, a typical hand drill turns at several hundred RPM. My rotary tool turns at 1000-5000 RPM.

It might work to use a rotary tool at a low speed (1000 RPM), but I wouldn't use one at a high speed except maybe for a final polishing with a non-abrasive buffing compound.

[Stan Pope]

Which brings a question to mind, Does anyone??? know if you can you use the Pro-Wheel Shaver with a rotary tool? Hint Hint Hint!

In the Cub Scout program, the kit insert shows a crude form of lathe turning ... a very crude form. (Wheels are fitted onto a nail which is chucked into a hand drill, and the wheels are turned against sandpaper on a flat surfaced block.) I interpret the example as intent to permit removal, by lathe-like action, of enough tread material to achieve radial symmetry.

I presume the "Shaver" is a variation of lathe turning.

The underlying concept of lathe turning is to produce radial symmetry in the wheels, i.e. the distances from the center of the wheel to the inside of the bore and to the outside of the tread is constant all the way around the wheel.

Some organizations and local rules do prohibit "lathe turning". In the Cub Scout program, there are NO NATIONAL RULES! Local rules dictate.

The kit insert also lists "common denominator' rules which are variously interpreted to mean "You can't tamper with the tread." and "You may lightly sand the tread to remove imperfections." and "You may work the tread surface provided the profile remains flat." and "You may reshape the tread profile and/or sidewalls and/or hubs to your heart's content." Similar variations exist for the question of axle location and use of pre-cut slots. (Slot usage and retention of wheel base spilts aobut 50-50 across the country.) And these variations are just between groups that claim to "follow the rules in the box."

[Stan Pope]

... I wouldn't use one at a high speed except maybe for a final polishing with a non-abrasive buffing compound.

Many years ago, I would polish the wheel tread. I found that this made the tread too slick. Slick treads allowed the wheels to lose their (rolling friction) grip on the track and slide sideways. Rear weighting compounds the effect, allowing the front wheels to slide too easily.

I prefer to leave the tooling marks on the tread. These marks are almost perfect lines around the tread circumference and contribute to fighting sideways sliding.

[MaxV]

You can still see a visible burr (tiny hole), but it feels smooth to touch--even across the burr. He hand-sanded each for about 2-3 minutes. Was that enough? How do we do it just right?

The mold mark dimple on a BSA wheel is generally pretty deep. So you have to take quite a bit of material off to eliminate it. However, since the dimple is an 'innie', it isn't necessary to remove it.

As others have stated, lathing is the only sure way to get a round wheel with no dimple. But this isn't always allowed by the local rules.

That’s a great question and in a timely manner. Maximum Velocity just sent out an e-mail announcing a new tool to help with wheel tread.

The Pro-Wheel Shaver is a hand-powered 'lathe-like' tool. It is currently in pre-introduction (former customer's only), but will be generally available on October 15 on the Maximum Velocity web site. I'll make a post in the 'Derby Products and Services' section at that time.

[gpraceman]

I’m new to this forum and don’t 100% fully know its policy regarding talking about or pitching an active member’s product so I’ll leave it at that. Just go to the web site.

Make sure to check out the forum's FAQ / Rules page for the policies on advertising. Basically, you are Ok as long as you don't become an advertising conduit for a merchant.

[Cabrzama]

So it sounds like what we did might be just fine. If not now, I do want to experiment with "lathe turning" at some point. Our local pack has few rules, certainly nothing that is really defined so I'm sure we could get away with lathe turning--if everyone hear feels like it provides a significant advantage.

What's everyone think? Big advantage or just maybe a small one?

I was going to polish the wheels smooth, but I think Stan made a compelling argument not to. I also saw one of those bits that Stan describes for lathe turning in my local hobby store for just a few dollars.

[Mike Parrish]

I'm sure we could get away with lathe turning--if everyone hear feels like it provides a significant advantage.

What's everyone think? Big advantage or just maybe a small one?

I always (when rules allow) lathe turn wheels. I believe it helps alignment and performance when everything is concentric around the hub.

[Stan Pope]

I believe it helps alignment and performance when everything is concentric around the hub.

This belief is well founded in both theory and practice.