First attempt at rail runner.... I'm going to need a little guidance!

[92hatchattack]

Hi all!

You guys have helped me year after year and I am going to call on your guidance again. This year for my sons scout race we are going to attemp our first rail runner. I;ve read a bit about this but have never done it before so I am a little scared.

Heres what I am wokring with. Rules say stock wheels and axles. Will polish and debur axles as usual. Rules say stock wheelbase must be used. Nothing that says we have to use the stock slots or that we cant move the position of the wheelbase. I've got a second hand Goat Boy drill block on its way to me that will let me drill my canted rears and nice straight fronts.

So pretty much I am just going to use this thread to shout out questions and ideas as they come to me. My first questions off the top of my head that are bothering me are:

1. My rules say we must retain stock wheelbase, front to back, and side to side. This means if I am playing by the rules I can't shave off that 1/16-1/8 of an inch on the fdw side. How does this affect me? Is this going to be a big problem?

2. Should I move the axle location of the rear wheels back further than the stock placement in the BSA kit, or would there be no real bennifit?

Thanks guys, your the best!

 

[HMH Racing]

Some guys do not shave that 1/16th off the front. With the canting of the wheels, The rear naturally angles away from the rail and front will angle towards the rail.

Yes, I would move the rear axle as far back as possible.

 

[92hatchattack]

Is there any like stadard for where exactly to drill my rear holes and weight placement? I dont want to get too aggresive with my COM on my first shot at this.

 

[bracketracer]

If you're using 1/4" cubes for weight, I would drill the rears at 1/2 the wheel diameter so the wheels are as far back as possible. That puts the axle very close to the weight and sometimes the axle hole will break through. Since you're new at this, you might want to put it a little bit more forward, say .650" or .700" just to be safe. If you're using a different kind of weight, you'll need to experiment a little by stacking your weight and wheels on top of the body to see how it balances out.

 

[92hatchattack]

Sounds good, thank you. Any tips on where, and how I should bend my FDW axle? This is my first time doing so.

 

[Rocket car]

I bend mine in a old drill press or a vise. Cut a notch in the axle and it will be easier to bend.

 

[bracketracer]

On BSA axles, after the axle is polished, I drop it through the wheel and put a Sharpie mark where it exits the wheel to mark the bend point. Pull it out, clamp it in a smooth jaw vise with the mark just visible, and use a small hammer and a dull flat blade screwdriver on the bend point. Our rules don't allow grooves of any sort in the axle so I bend without a groove. (On aftermarket axles I always cut a groove). Go lightly with the hammer, it's easy to add more bend but it's harder to take it out if you overshoot.

Also try WWW.5kidsracing.webs.com There's a ton of scout racing info there.

 

[BulldogRacing]

5 Kids info is amazing, I've used his info to help teach cubs and boy scouts the proper way to build a fast car.

 

[92hatchattack]

Thanks guys!

So far so good for me. I've got me rear axles drilled at 5/8" from the rear with 10 cubes in the back. (I know I could have gone 12 but I dont want to get my COM too aggresive on my first try at a railrunner) Got my slot in front of the axle drilled for weights too. And front wheels drilled straight of course. Its taking a bit of time but It's fun to try something new. Haha, I hope all this work doesnt blow up in my face when that starting gate drops. Haha!

Question. Nail Polish. What is the specific type everyone uses and what stores carry it? Im afriad I am out of time for ordering things online.

Thank you!

 

[HurriCrane Racing]

Sally Hanson Teflon Tuff. I had to order it on line.

 

[92hatchattack]

Bummer, with tomorrow being a holiday I'll never get shipped here on time. I found it on amazon but they dont offer expidited shipping on this particular item. Oh well. Not that big of a deal.

 

[ngyoung]

Its not a deal breaker. Just one of those things that can maybe shave a small fraction of time off. You can use CA glue and sand it like you did your axles. Another option is monokote trim piece. It has a peel and stick backing and can be found at local hobby shops. Just going with raw wood and burnished with graphite still works as well.

 

[92hatchattack]

Question, If you could have your axles polished on life a professional polishing machine would you use that instead of the deby dad kit? I have the kit but for the last 3 years I've been polishing on a polishing machine. Is one beter than the other?

 

[92hatchattack]

Hey guys, how does this bend look? Do I need to go a little further? It looks slightly more bent in the picture to me than it does in person. I'm probably starting to overthink things.

 

[Quicktimederby]

I bend mine where the wheel can just slide onto the axle without binding. You still have a ways to go on your bend.

 

[LightninBoy]

Question, If you could have your axles polished on life a professional polishing machine would you use that instead of the deby dad kit? I have the kit but for the last 3 years I've been polishing on a polishing machine. Is one beter than the other?

Hard to say. I'd polish one up using the derby dad kit and use the machine on another. Then inspect each axle surface under a 60x lens. Use whatever looks better.

Make sure you check under the nail head too! Could be a bigger distinction there.

 

[92hatchattack]

Ok, is this better or do I still need to bend further? (fyi car is just an old scout car from our first year)

 

[ngyoung]

I think it is good now. If it is a 92x axle you dont want to go too much more or you will not be able to get the wheel on.

 

[92hatchattack]

Its just a stock BSA axle.

 

[ngyoung]

Then it will be more forgiving if you go a little overboard. I eyeball compare it to the angle of my rear axles which are drilled 3*. Tuning can get more touchy with an extreme angled DFW but I don't think you're that far yet. Looking again at the wheels installed I may go a little more if you are showing it with the bend pointing straight down.