How To Drill Axle Holes without the Silver Bullet

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timmi20

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Oct 16, 2014
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These forums have been awesome for a newbie like me, thank you all.

My sons race is in a few days so I do not have time to order the Silver Bullet (although I will so I have it ready for next race).

Since I do not have the Silver Bullet yet, I would love to have the Silver Bullet in hand, but the race is in a few days and I need to drill axle holes.

I understand how vitally important the axle holes are. Since I do not have the Silver Bullet yet and will not be able to get one prior to the race, can anyone shed some light on the best alternatives to the Silver Bullet for someone in my case?

I will be racing on a track with outer rails, 4 tires but only 3 touching.

Any help would be appreciated.
 
I have used a second block. I clamped the block I'm drilling to another block. I'm not remembering exactly, but I believe a 5/32" drill bit at the top of the side of the bottom block will result in a drill angle of 6 degrees (I recommend you do the math instead of trusting my memory).
The math:
Code: 
height of block x sin(angle you want) = drill bit thickness

Also, in your track scenario, you'll want your dominant front wheel (DFW) at a negative camber (bottom further out than the top) and steering to the outside. You'll also want your rear wheel on the dominant side to be inset by ~1/8". Not sure what to recommend as to camber on the rears; although it's been posited that a positive camber would be best. It's hard to say though, as that track style is quite uncommon.

Good luck!
 
+1 Good advice!

You also want to run that dominant front wheel in reverse so the smooth edge runs the rail and not the wheel lettering. See what you can use as a hub to keep a tight wheel gap.

Is it a BSA race? What other rules might we need to be made aware of?
 
Thanks a ton guys, trying to absorb all the info in a short amount of time, it is my sons last year in cubs so I really want to get it right for him.

It is a cub scout bsa race, not very strict rules. I have the wheels and axles from DD4H already. Just need to figure out the axle holes. It is a really interesting track, wish we were using a normal track, but oh well.

It is made of plastic with sloping sides. It looks sort of like this if you were to look down the track, but with more sloping sides than this.

______/

I cant figure out how to post a photo on here.
 
Sloping sides? Wow. That being the case, I would have to recommend very light amounts of steer -- like 1" over 8' light.

What does the start look like? A flat, leading over a hump, then down hill? Is there a flat section of the track on the floor, or is the whole track a slope? These questions would determine where to place your weights (or if it matters much).
 
Here is a link to the photo of the track

https://www.dropbox.com/s/nlpni9sn3izgbac/2014-10-21_14-38-35.jpg?dl=0

It is a slope, like a normal track. It slopes for awhile then flattens out.
 
2014-10-21_14-38-35_zps1a068b14.jpg

I've never seen a track like it. How many lanes is it? The colors say "4", but the dividers and light on the end say otherwise.

With the track ending on a flat, and starting on a slope, you'll want your weight toward the back of the car. Put your rears 5/8" from the end of the car. Add weight behind the axles, then add the rest of the weight in front of the rear axles, shooting for a CoM (Center of Mass) of 3/4" - 1".
 
I agree, weird track, but it is what I am having to deal with /images/boards/smilies/smile.gif.

There are 8 lanes, the race moves along really quickly.

Having seen the track now, what do you think on the cant of the rear/front axles?
 
a quick way
2X4 cut into 7"X1.5"X2"
clamp bottom of car to the 2" side of the block of wood
with top of car toward you, tilt back and insert two Pennies (one on left, one on right) so you can see half the penny yet.
drill only the backs! make sure the holes are directly across from each other.
 
Thank you all for the advice. Giving the type of track I will be running on, do you think the front wheels should look like this with one of the wheels slightly raised?

/

And the rear wheels like this?

/
 
Fronts should look like this | and backs like this. /

The angled one on the front is your drive wheel. The straight up and down one is your lifted wheel.

EDIT with a track like that I would make the car steer straight as possible. I think the car will wiggle no matter what, with a track like that.
 
Rocket - His track has no center rail. DFW should be cambered the other way. Rears - undetermined (though I think that /-- might be fastest)

3Phase - I don't know. Not likely. The idea is to have a drill bit squared to the table, and then to lift the block so the drill goes into the car at an angle. With no drill press, one of the DW-style tools would probably be best. But, a decent drill press can be had at Harbor Freight in the <$80 range.
 
If it were me, I would probably would forego the canted rears as it may prove to be difficult to get the same cant on both sides and just try to drill accurate straight axle holes. Be sure to use a fence to account for the table not being square to the drill bit.
 
If you don't have the proper tools do not drill holes. Use the slots, you know the rear wheel alignment will be correct. Just insert the wheel at a slight cant, you won't need much on that type of track. Your FDW you want on a negitive cant also.( top of the wheel towards the body) I would definitely index in the rear wheel right behind the FDW. I would steer it away from the nonDOM wheel about 2-3 inches. Make sure the non Dom wheel never touches anything and you'll be good.
 
Even with the picture, I don't quite comprehend the track layout.

Is this what you mean? I.e. The red | is the track edge. The blue / are the wheels. And the ------ is the car's body:

|/-----| (back); and ||-----/| (front)?

If that is what you mean, i.e. especially the track edges?

Then my opinion is run the back with a 3 degree outer camber, and the DFW an inner camber, but drill the rear body holes with a camber, but not the front! Both front body holes should be drilled straight, with the NDF hole a bit (1/64") higher. The axle on the DFW wheel should be bent with a screw driver slot on the outer head (don't bend it yourself, just buy it from DD4H). With a screw driver, move the DFW axle back and forth, test it on a 4 inch table until the car drifts 3 to 4 inches towards the NDW's side.

All wheels should be installed backwards, with the lettered edges facing the body. Polish all wheel's outside edges, and also put graphite on the outer edges of all wheels. If you are allowed to use oil, use it only on the wheel bores, but be careful that none of the outer edge graphite comes anywhere close to the wheel bores. IMHO
 
This is the coolest question in a long time!

You deserve a door prize of a pink right Gee fender just for posting it.

Nothing like a luge track!

OK Timmi,

This is what ya do.

No cant in the rears.

Negative cant on both wheels up front, with 1 of em raised up a bit.

Everybody set to run straight.

You will smoke em!
 
Maybe this is what QT said, didn't catch it all...but, how bout the front DFW inside out, camber with bottom edge out, extended out a tad more than the rears (which are on a standard camber), very slight steer into the outside rail on DFW side? This is given the outside lane edge is vertical enough to keep the DFW from climbing up it. Inside out rail running?
 
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