Personal experiences with "slots required" rule

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Noskills
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Personal experiences with "slots required" rule

Post by Noskills »

Hello all,
I have seen people state that in order to get better performance out of using the required slots, people fill them with epoxy and drill holes into this. I have two questions:
1. From experience, are judges OK with this?
2. Is epoxy transparent enough to allow axel inspection?

Thank you,

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drathbun
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Re: Personal experiences with "slots required" rule

Post by drathbun »

When I have used the slots I insert the axles and get my alignment where I want it to be, and then I epoxy only the inner portion of the nail, leaving about 1/4" exposed towards the wheel. I'm not sure an inspector could tell the difference between that process and what you describe, or if it makes a difference.
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Re: Personal experiences with "slots required" rule

Post by 5kidsracing »

If you must use the slots per your rules, but you want to drill your own holes then this a good method and I have done it many times. You could drill holes and then connect them with a cut slot, but in my opinion I think that shouldn't pass with these rules.

Take your stock BSA pwd block and use a 5 minute epoxy and fill the ends of the slots. Fill just the first 1/4" of each slot.... use a pin and get the epoxy all the way down in the slot. If it is high or comes out the end a little that is ok. Let it dry overnight so it is fully cured. Epoxy doesn't drill very well so you want it hard and fully cured. After it is cured then place a piece of coarse sandpaper on a flat surface and gently sand the sides and bottom flat so no epoxy is sticking out. Now drill your axles holes with whatever method you pefer for whatever canting or straight set-up you want. Drill your holes at the top of the slot so you hit some wood. Drill very slow and carefully. When you install your axles the tips will be visable for inspection. If you drill right you will have a perfect set-up and you will have used the slots and met your rules. The only difference between this method and using the axle slots the normal way is that you glued first and drilled second.
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Re: Personal experiences with "slots required" rule

Post by rpcarpe »

Haven't run into any rules 'round here that require slots... but the method from 5kids so very useful.
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Curse You Red Baron!
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Re: Personal experiences with "slots required" rule

Post by Curse You Red Baron! »

Our Pack has that rule. My scout and I have effectively used 5-min epoxy, JB Weld, and wood filler (had some problems with dried filler 'popping' out of the slot, but hole was straight and car performed well.) Same basic approach as 5kids, so nothing new to offer there. We don't have to show axle tips, so I imagine you could just not fill the middle of the slot.

This year we had a 'happy accident'. Used an epoxy based woodfiller that had an inner core and outer section that you were supposed to mix. In a hurry, we didn't realize this, and there was little 'mix' in our epoxy, so it didn't fully cure - but it held well. We drilled anyway. This was our first time drilling pre-canted (rear) axle holes, and the fwd/bkwd alignment seemed to work alright, but we got the cant/angle too severe. The give in the un-cured epoxy gave us some flexibility to adjust the rear axle cant without having to re-fill and re-drill. Our alignment seemed to hold, and we ended with a faster car than we deserved. :whew: I don't know if this information might be useful in the 'micro-vibration' discussion that took place on another thread.
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5kidsracing
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Re: Personal experiences with "slots required" rule

Post by 5kidsracing »

Another maybe more advanced detail about drilling axles holes....

With a drill press, you should always use a center drill first, especially when drilling canted holes. I know this may be above the scope of the "once a year" builder, but it is very important. You also want to make sure that the fixture you are using to drill the axle holes is held in position somehow. Every drill will walk, the stubby ones are much better than the regular drill bits, but they can also walk. You have to pick the right size center for your application and they are in sizes from 000, 00, 0, 1, and on up. I believe for standard axles holes you want to use a "0" center. Of course in order to do this on a drill press you have to make sure the component you are drilling cannot move. It makes no sense to center drill a hole and then change tools and drill the hole at a slightly different location.
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Re: Personal experiences with "slots required" rule

Post by FatSebastian »

5kidsracing wrote:Another maybe more advanced detail about drilling axles holes....
Hearing that drilling epoxy can be rather tricky, what would be the recommended drill speed (RPM) for drilling epoxy holes? Is there a particular kind of bit that is better than others?
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Re: Personal experiences with "slots required" rule

Post by 5kidsracing »

FatSebastian wrote:
5kidsracing wrote:Another maybe more advanced detail about drilling axles holes....
Hearing that drilling epoxy can be rather tricky, what would be the recommended drill speed (RPM) for drilling epoxy holes? Is there a particular kind of bit that is better than others?
I run mine at 1400 rpm, but honestly I don't know if that is the right speed.
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Kindintentions
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Re: Personal experiences with "slots required" rule

Post by Kindintentions »

Is this 5kidsracing method still the best method for drilling canted holes when the rules say you must use the built in axle slots?
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Re: Personal experiences with "slots required" rule

Post by Speedster »

Kindintentions, let's talk about this. I'm going to assume you are involved in BSA scout racing.

Your intention is to drill holes so your back wheels will have a 2 1/2 degree Negative cant on them.
This is what you will be dealing with:
A piece of Pinewood
A junk nail that has a diameter of about 0.087
A junk plastic wheel that has a bore of about 0.097. That's a lot of slop. (This is from a print out from AD&N Productions, Oak Grove, MN.). I'll send you a copy if you would like to have one.

I'll have to guess about the rest.
The cheapest drill press, like I have, from Harbor Freight.
The #44 drill bit that came with the Pro Body tool you purchased from Hobby Lobby.

We know what your Intention is. After you install the rear wheels they are now going to be 2 1/2 degree Negative cant and they are going to be perfectly parallel to the body of the car. If they are not, you're done. There is no further adjustment.

OK, let's try this.
You have the Pro-Body tool and probably the Pro Axle guide. That's fine. Unscrew that metal piece and throw it away. Use a plastic credit card for your wheel clearance. That metal piece can easily damage your bores. I also like the Pro Axle Bender from Maximum Velocity, $79.95. You have now taken a few minutes spreading and squaring your slots and bending your axles to whatever degree you choose. The nail heads have all been marked with a sharpie so you have a starting point. You can now set the wheels to be square to the body of the car by turning the nail head with those fancy pliers from Maximum Velocity. With the front wheels off, the car set parallel to the test board, the wheels should migrate to the axle heads while moving forward and backward.
Wasn't that easy?
Kindintentions
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Re: Personal experiences with "slots required" rule

Post by Kindintentions »

Speedster,

Thanks for your help. I was actually trying to avoid bending the rear axles and instead drill canted axle holes as discussed here -http://stanpope.net/camdrill.htm. However our scout rules stipulate "The built-in axle slots in the block must be used." and "The axles and axle heads must be visible to allow for inspection." So I thought if I filled the slots with a clear epoxy as outlined above then drilled it for a negative camber, it would work better than just inserting them on an angle and hoping for the best. Plus, given that we have to use the built-in axle slots and they are out of square, this would help straighten out our axle slots for straight running.

The first year we inserted them at an angle and came in 2nd in our heat but did not place in the finals. Last year we used bent rear axles and did not place in either the heat of the finals. Hence why I wanted to try drilling for a negative camber. We still plan on bending the DFW this year.

P.S. I also have wood glue and wood filler that I have used for parts of the body of the car, if that would be better to fill the axle slots.
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Re: Personal experiences with "slots required" rule

Post by Eagle »

Seems like a silly rule. What exactly are they inspecting for? And, how does seeing them help in that endeavor?

That being said Clear epoxy (which isn't always clear at any thickness is likely your best bet.

Then if you have a Clear Jig it is super simple to drill all your holes. You can even get a 5 hole kig and run the front reverse canted on a straight axle.
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Re: Personal experiences with "slots required" rule

Post by Speedster »

Those slots are close enough and the Pro Body Tool will make them even closer if that's what you want to do. I don't bother doing that to the slots anymore. I bend all my axles to 1 1/2 degree, except for the raised one which is straight, because of our rules and it has worked fine for us for lots of years. The ability to control the "toe" with a bent nail will give you what you want.

Why do you bend the nail on The Dominant Front Wheel? You do that because it will give you the ability to set the car on your tuning board and adjust it to drift exactly 2" in 4'. You then take the car to your Best track and do the final adjustment. When setting the back wheels to run parallel to the body of the car you're doing the exact same thing.

January 25, 708 AM.
Kindintentions, I read your January 24th Post again. You wrote "Scout rules stipulate" etc. You don't insert the nails on an angle. You have used the Pro body tool to square the slot to the block and spread the axle slot to an .086 hole with your #44 drill bit. Now clamp your Pro Axle guide tight to the block and push them in with your drill press. Don't go so far that you can't get on the heads with your fancy pliers. Use the block of wood you have drilled a 1 1/4" hole in so you don't damage the opposite wheel. Adjust the rear wheels to roll parallel to the block. Using a Credit card for clearance gently push the nails in until they touch the Credit card. Glue the axles in with No Sag Super Glue. I know, I know, everyone is going to tell you to not use Super Glue. Do it anyway.

If you don't have a Pro Axle guide and a block with a 1 1/4" hole drilled in it, email me, Send me your mailing address and I'll send them to you. No Charge and FREE shipping. Yours to keep.

PS. I know Noskills very well. He and his son built very, very Fast cars. As far as I know he never drilled holes for his axles. We all laughed at his Derbytalk name. The man is a Medical Doctor.
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Re: Personal experiences with "slots required" rule

Post by Kindintentions »

Speedster,

After your advice and discussion with my kids we have decided to try the 1 1/2 degree bend this year and see if that works, instead of trying to insert the axles at an angle and get them wrong or slightly off which would cause even more problems.

I had not heard the advice about using a drill press to insert the axles, so I will try that on an old car first to get the hang of it and If I like it I will use it on this years cars.

I sent you a PM also.

Thanks for all the help!
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Re: Personal experiences with "slots required" rule

Post by Speedster »

Sporty used a Drill Press. I miss him.
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