Scaley/Slot it F1 Crown gear issues !!

[chrisguyw]

As some of you have already discovered, or, are about to discover, there can be some issues in using aftermarket (Slot-it) Crown gears in the Scaley F1 cars. The issues do not affect all of the Scaley F1's, and there are two distinctly different issues that may arise, again, depending on the model you are working on.
As the chassis plates and the engine cover bodywork do differ model to model you may discover that you either have a Crown gear diameter issue, or a Crown gear face width issue.......some cars have none, some one, and, yes....some both.

So first,....diameter issues.

The standard Scaley inline Crown has 27Teeth , and a diameter of near enough to 14.75mm, while the Slot-it 27T Crown has a diameter of 15.25mm. While they are both 50P metric, the Slot-it Crowns have a taller depth of tooth, making them a tad taller in diameter. As the rear ends of the Scaley F1's are tightly packaged, any gear with more than a 14.75mm diameter is likely to rub,make noise, and cost you time. !!
While you can reduce the dia. of the Slot-it 27T to 14.75, it may be wiser to replace the Crown, with a 23 to 26T Slot-it Crown, and, to achieve a gear ratio in the 3:1 range, a swap out of the pinion, to an 8T is necessary.......(8 x 24 using Slot-it gears, obviously replicates the stock Scaley gear ratio).

Gear width issues.

More often than not, the cuplrit is the width (and back edge shape) of the Slot-it gears........they are quite beefy in their manufacture, a full 0.5mm wider than the stock Scaley, and the back edge is "square", not radiused like the Scaley.
So...........again, with the tight tolerances on the Scaley body/chassis, it is very common for the back edge of the Slot-it Crown to interfere with either the chassis plate, or the upper body work.

So what to do...????........There are other Crowns on the market that have a thinner profile than the Slot-it (JK,Red Fox, Voki, etc.) but these all have drawbacks when used in our plastic toy cars, the main one being that most are 64P, and while this in itself is by no means a drawback, 64P gears are sensitive to any misalignment issues, and the relatively filmsy rear ends of most Plastic cars (especially the Scaley f1's), are far from ideal when considering a 64P gear.

So, considering that most everyone has some Slot-it Crowns, and that they are inexpensive, relatively good quality, and easy to work with, lets stick with those !!

So the goal is to remove the "hard rear edge" of the Slot-it Crown, and to reduce its face width.........

Step one....mount a Slot-it Crown on a tire truer, (any tire truer works), or on an axle, and in an electric drill. Installing it with the "hard edge" out gives you more room for the next steps. (see pics.)

On a Hudy



On an axle, mounted in an electric/cordless drill/dremel



With both the tire truer/drill powered, radius the rear edge of the Crown with an emery board, sandpaper, or dremel/cut off disc (I prefer the dremel route, but the less adventurous among you may prefer the less intrusive options ;)
If using a dremel/cut off disc, you find it easier to cut at a 90 degree angle to the crown.

This is not the best pic. showing the 90 degree angle of attack but, it does show how you want to profile the back edge of the Crown.....



A few Crowns after surgery.........stock Crowns on top, modified below

******* When you have radiused the rear edge , check it in the car.......still rubbing???,........more material to be removed.



At the outset, I mentioned that Slot-it Crowns are "beefy", and they are, allowing quite a bit of material to be removed, with no issues.
The modified 24T Slot-it Crown in the following pic. (the one on the right ;) ), shows how much can be taken off without affecting the integrity of the gear........this modified Crown was done 5/6 years ago, and has been through 2/3 seasons of Scaley F1 club racing, and well as hundreds of fun laps......a little dirty, but, still as good as new.
I have modified dozens of Slot-it Crowns this way for friends/club guys, with no issues at all.





Hope this helps !!

Happy Motoring
Chris Walker

[Audi1]

It helps a lot, Chris - thanks!

But, what can be done about the other end; the metal end? Can it, too, be machined down to lessen some of the width issues?

Separately, I would think that going to an 8 tooth pinion would also help with brakes on the car, since slimcan motors with relatively low torque are not generally known for their braking qualities.

Allan

[chrisguyw]

[Modernslots]

Thanks Chris - you saved me from lots of heartburn lol !
Rob

[Old23]

Chris, you are a national treasure... and an international one as well! Thanks for spreading the wisdom around. :clap:
Stewart

[HomeRacingWorld]

Yes, solid gold information sir. Well done!

[TuscoTodd]

Great tutorial and pics!
Thanks for sharing!

[GTOking]

Great information! I have needed to file down the edge of a crown to clear a motor screw a couple of times. Glad you have shown how far one can go on these crown gears, in the past I would have been reluctant to go that far and turned the Dremel to the chassis and/or the body. Thank You for sharing.

[chrisguyw]

[GTOking]

[Mark]

[Audi1]

Thanks for bring up these points. I've made modifications to the Rules to address the chassis/body modification questions, as well as some rear axle upright concerns. Take a look at revised Rules 4. and 5. in the Formula 1 Proxy Rules and Registration thread.

Allan