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4/4/07

Moonstone Gears

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When I first heard of these gears, I had a different type of test in mind to perform. It would have been exactly like the RTHO tests. Then, after a little contemplation, I decided to take a slightly different tack. More on that later in this review.

I used the same gear plate and chassis as in the other test. I thought that would be important for an apples and apples comparison. But I thought to add a second test for these gears.

We decided to use the data from the stock gear tests in the RTHO review. To remind you, we first, took a set of stock gears, hand picked, checked for roundness, and centered hole, and Installed them on a known good gear plate (donated by Steve Ward). These were lapped prior to installing. Nearly 30 gears were checked to find the 3 we used. We then hooked them to a good chassis and armature, with axle and crown gear, and spun it up, taking measurements with a tach, and see what we get. Then, with the same setup, take off the gears, and mount the Moonstone sets. Again, check with a tach. We decided to see how three different sets of Moonstone compared. We did this to get some idea of quality control.

Power source was a 20 volt Aurora power pack. The tach we used gave us both highest, and average RPM readings. We decided to report both, because if the high was near the average, it did show some stability in the system. We started with the stock gears. we ran the test for 15 seconds. The figures for average, and high were 24,376/25,740.The results for Moonstone gears are as follows:

Moonstone 1 - 22756/24010

Moonstone 2 - 23183/24395

Moonstone 3 - 22659/24423

As you can see, the numbers were a little lower than the reworked stock gears, but with the same consistancy. Also, it is important to remember that these gears were random, and not picked through. The measurements we took for roundness and centered hole showed them to be very accurate, but they were a little noisy, as is.

We decided to see what would happen if we lapped these gears. Using Simichrome, with a little oil, we ran them in for about 2 minutes. We did this on a separate chassis, and we powered the chassis by hooking it to a Dremel.

The results that follow are very interesting:

Moonstone 1 - 24815/25503

Moonstone 2 - 24791/26175

Moonstone 3 - 24712/25418

As you can see, lapping helps these gears a lot, and the difference between high and average was less after the procedure. The gears also showed to be very consistant after lapping.

Driving with the gears was eshewed for a more subjective look at technical data. I think the results indicate an very good product that could be the answer for many people's style. IROC for example. With a little effort, these would be Fray competitive.

To sum up, we found only one concern with this product. The holes for the idler are slightly under-drilled. This is not a big issue, and if one drills or reams to .010" +/- .001, they should be fine. The gears are perfectly round, and centered, so that won't be an issue if you find a good gear plate (all these after-market gears are only as good as the chassis). The fact that lapping and drilling the idler helps them was no big deal for us, but it does add to the level of setup, if only slightly. Picking through gears is eliminated, though. We randomly picked the gears out, and all the sets were quite consistant, as to performance.

The Moonstone Gears were designed to help the average builder make a decent car without having to dig through 100’s of gears to find the perfect set. I also looked at the cost factor in these gears and didn’t want to spend $30 a set for a T-jet.

 

These gears are machined to perfection by a machinist who has over thirty years in CNC machining. He has made these gears with his best knowledge of information that was given to him. Some gears are made to look a little different than stock and should only be used if rules allow them. My gears are perfect examples of what a stock gear should look like if it was made 30 years ago. These gears can pass for stock and work well.

 

Some of the main questions I have had asked.

 

Q- The idler is tight on the post

A- Try more top plates or boil the chassis with the gear in it.

 

Q- They are noisy.

A- Most stock gears are noisy just lap them in and you will have a quite gear set.

 

I am working with the machinist to see if we can get them a little quieter. It may take some time but we can work on it. Will my gears ever be like the competitor?  Not a chance. The machine he uses is very intricate and can cut more gears in less time. This makes it more cost effective for all of us.

 

If you want to try these gears out visit my website www.moonstonebodies.com and you can order all your gears and other parts for your T-jet there. Also look at the bodies we make for all your racing needs.

 

Keep it in the slot and speed on.

Dan Luna