Using slots rule question

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Pinewood Po
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Using slots rule question

Post by Pinewood Po »

I have another grandson that has joined scouts and I have been ask to help him with his car. I very much enjoyed helping my other grandson with his derby car and learned a lot right here on this forum. Thanks to all of you.

This grandson happens to be in a different district, with different rules. As part of the rules, Rule 1 g. states, Do not lengthen or shorten the wheel base of 4 1/4 inches. Use the precut axle slots. If the precut slots are not square you may make additional slots or drill axle holes to insure proper alignment as long as the wheel base and track clearance is maintained.

That rule is ridiculous in my mind. I much prefer to drill holes than use the slots. Drilled holes are allowed, but only if the slots are not square.

I want to teach my grandson to play within the rules and to be honest but this rule seems crazy to me. I guess I can always hope the slots are not square.

What would you do? Drill and forget it.......or live with the slots?

Thanks for your input.
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Re: Using slots rule question

Post by macd »

What would I do?
-- Drill my own axle holes.

If you want to optimize speed, you would only drill your own axle holes if you think your can improve upon the slots.
If you have a drill press or other tool that can make holes or slots that are "more square" than the pre-cut slots, then you have met both the spirit and the letter of the rule.
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Re: Using slots rule question

Post by Speedster »

I'm wondering about that 4 1/4" wheelbase. How accurately are they going to measure the wheelbase? Is it not 4 3/8"?
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Re: Using slots rule question

Post by FatSebastian »

Pinewood Po wrote:That rule is ridiculous in my mind. I much prefer to drill holes than use the slots. Drilled holes are allowed, but only if the slots are not square.
Welcome back, Po! Whenever a rule sounds ridiculous, I first want to suppose that it is badly worded, such that there is an alternate interpretation that makes more sense.

In this case, I wonder if the rule may be intending "If the precut slots are not square you may make additional slots or drill axle holes [in the precut slots] to insure proper alignment..." Thus, I suspect that inspectors are expecting to see slots of some kind.

Regardless, you should ask a local race official to be sure.
Pinewood Po wrote:What would you do?
I cannot recommend drilling pre-cut slots because the bit may wander, and the nail would probably be too loose. If allowed, we would drill (using a drill press) and then cut a slot underneath those holes if slots are intended.

Otherwise we would start with a block with square slots and follow general DT guidance on inserting axles into slots, prepping the slots with a nail in a drill press.
Pinewood Po wrote:I want to teach my grandson to play within the rules and to be honest....
Yes, this is paramount.
Pinewood Po
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Re: Using slots rule question

Post by Pinewood Po »

Thanks for the replies!

My intent, before I got to see the rules, was to build a dog tracker as I did with another grandson. The first thing I looked for, after receiving the rules, was anything that prohibited drilling axle holes. As Sebastian mentioned, it's possible the rules intent is to keep the slots and true up by drilling. That never crossed my mind.

My limited experience tells me the slots are not a good idea in the first place. There were several cars at the first derby I attended that had problems keeping the axles and wheels attached to the cars.

As Sebastian suggested, I will have my grandson get some clarification on the matter. If need be, I will deal with the slots.

Again, thanks for the replies.

Po
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Stan Pope
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Re: Using slots rule question

Post by Stan Pope »

Pinewood Po wrote:My intent, before I got to see the rules, was to build a dog tracker as I did with another grandson.
If we mean the same thing by "dog tracker," you can still do so if you are allowed to put some bend in the axles. Then turn the top of the rear behind the DFW slightly back and the top of the other rear slightly forward. Alignment will be touchy, so see my web page on Cambered Alignment.
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Re: Using slots rule question

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Stan Pope wrote:
Pinewood Po wrote:My intent, before I got to see the rules, was to build a dog tracker as I did with another grandson.
If we mean the same thing by "dog tracker," you can still do so if you are allowed to put some bend in the axles. Then turn the top of the rear behind the DFW slightly back and the top of the other rear slightly forward. Alignment will be touchy, so see my web page on Cambered Alignment.
Stan,
We are talking about the same "dog tracker". You and I had a discussion about this a couple of years ago when I thought I was on to something new. Turns out you had already done it long ago.

Since we do not have a test track I did it a little different with the way I drilled the holes. The car did really well without bending axles. The dog tracking alignment is built in by the way I drilled the holes. It avoids the "touchy alignment" you mentioned but still dog tracked really well.

Po
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Re: Using slots rule question

Post by Noskills »

I have cut a slot below the axels holes with a hacksaw that looks like the original slot and allows for axel inspection. Others here on DT have also suggested filling the slots with epoxy and drilling into them. Also, I would say that you could make the argue that any out of the box block has an imperfect slot.
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Re: Using slots rule question

Post by Pinewood Po »

Looks like the way to stay within the rules is to use an end mill to make a larger than axle size hole in the end of the slots. Fill the holes with epoxy and after it sets up, drill the holes as I please.
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Re: Using slots rule question

Post by 5kidsracing »

Pinewood Po wrote:Looks like the way to stay within the rules is to use an end mill to make a larger than axle size hole in the end of the slots. Fill the holes with epoxy and after it sets up, drill the holes as I please.
That's what I would do... I have done this many times and it works fine. You don't have to drill a larger hole, you can just fill up the end of the slots with epoxy. Let the epoxy sit overnight until if fully cures and then drill very slowly with a stiff or short bit.
For my "Pinewood Story" go to: http://5kidsracing.webs.com/index.htm
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Stan Pope
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Re: Using slots rule question

Post by Stan Pope »

Pinewood Po wrote:Since we do not have a test track I did it a little different with the way I drilled the holes. The car did really well without bending axles. The dog tracking alignment is built in by the way I drilled the holes. It avoids the "touchy alignment" you mentioned but still dog tracked really well.
TTNN! Test Track Not Necessary!

Done on a two-sided tuning board.
Side 1 has a line drawn to measure drift.
Side 2 has a mock rail to measure rear wheel tracking relative to rail and relative to each other.
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5kidsracing
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Re: Using slots rule question

Post by 5kidsracing »

Stan Pope wrote:
Pinewood Po wrote:Since we do not have a test track I did it a little different with the way I drilled the holes. The car did really well without bending axles. The dog tracking alignment is built in by the way I drilled the holes. It avoids the "touchy alignment" you mentioned but still dog tracked really well.
TTNN! Test Track Not Necessary!

Done on a two-sided tuning board.
Side 1 has a line drawn to measure drift.
Side 2 has a mock rail to measure rear wheel tracking relative to rail and relative to each other.
Totally agree Stan.... At my workshop for our pack I hand out tuning graphics for the kids to tape to a tilted table. They can set their drift and then tape a yardstick to a specified area to check wheel migration, tracking and make sure the rears are off the rail. A scout definately doesn't need a track to tune on...

Image
For my "Pinewood Story" go to: http://5kidsracing.webs.com/index.htm
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Re: Using slots rule question

Post by Noskills »

I made a tuning board out of a four foot shelf board with a yard stick glued to one side. Works great.
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Re: Using slots rule question

Post by Pinewood Po »

Assuming I use the slots, how do you adjust (bend and/or turn) the axles when you are tuning on a test board?
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Stan Pope
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Re: Using slots rule question

Post by Stan Pope »

A number of ways:
(1) Grasp the head of the nail with pliars to rotate (around the nail's axis)
(2) Cut a slot in the nail head and turn it with a screwdriver like you would turn a screw. (This would violate some rules ... like the Wotamalo rules ... that require that the outside surface of the nail head be left "pristine.")
(3) Use a small file to create "flats" on the portion of the nail between the wheel and car body, and create a "wrench" thin enough to slip between. This gives excellent control and is useful when the step is removed from the outer wheel hub.
Stan
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