# Lapping JL Gears



## hrnts69 (Apr 12, 2007)

Has anybody seen a performance advantage when lapping JL gears with toothpaste? Since 2 of the gears are plastic, i dont think it would matter that much. But i may be wrong.

Post up your observations, comments on this subject.

Blake


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## dlw (Aug 17, 1999)

I never used any substance for lapping plastic gears..... too paranoid, perhaps. I just ran the car in both directions on a 9V battery or on low power on a track. Does the trick for me.


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## mahorsc (Mar 26, 2008)

a small amount ran foward and back for about 20 mins 
stay light on top gear a little heavier on pinion 
you can thin out a little 
i use soft scrub thinned with water 
the upper gears seem to take care of them selfs after about 75-100 laps car seems to free up and fly
i have built around 100 of these cars this is the best i have found so far
kevin


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## clydeomite (May 5, 2004)

I like to give the gears a " bath" in Brasso while spinning them via a 9 volt battery. I pour brasso in a soap dish and stick the chassis upside down in the soup and apply battery power. You can do the forward reverse deal it helps a little.. You will know by the increase in RPM's when to stop. Wash them off with a little soap and a toothbrush . After they dry off try spraying a little "Amour all" on them that's when they really spin free. but be carefull with the armourall if it gets down in the motor you will need to clean it all up. 
Clyde-0-Mite


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## bearsox (Apr 22, 2006)

*Heat ... like a soldering iron works when near a rolling tjet crown when chassis is running on a breakin box or pit pal as a lapping tool so perhaps worth a try on JL top plate gearing.

Bear :wave:*


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## demether (Aug 26, 2008)

I use toothpaste on my JL tjets gears, on 9volt during 15-20minutes, and after that I wash the things and oil it. I can feel the difference !

the toothpaste acts as an abrasive on the gears, to smooth them. it works, you can see the tooth paste changing color for white to grey. 

use a cheap white tooth paste !


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## tjd241 (Jan 25, 2004)

*Mike King...*

... has done a considerable amount of tuning and tweaking on the JL and AW tjet chassis. He builds what he calls a Fun-Jet. Here is a thread where he has revealed some great techniques when breaking in these chassis... http://www.hobbytalk.com/bbs1/showthread.php?t=162740&highlight=fun-jet

Worth a look if you like these chassis. nd


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## Bill Hall (Jan 6, 2007)

*No flossing required*

Ultra -brite toothpaste!

No exceptions here....cuz I have half a tube....LOL!

Water washable ....minty fresh

Proven results. Absitively fantastic on Four Gears and AFX pancake chassis with scrammbled or mis-matched gear sets! Dont forget to do the crown and your rear axle bores.


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## mking (Apr 25, 2000)

*lapping gears....*

I use a wire brush attachment in my dremel

i know, i am abusing the poor plastic gears. 

but its very fast, it works very well, and you dont need to clean up all that brasso or toothpaste. 

i am very lazy. 

i put the top plate in a bare chassis with no magents. turn the dremel on low speed. lightly touch the brass pinion gear with the spinning brush, which will cause the gears to spin. move the brush to make the gears spin the in opposite direction. lightly move the brush over the plastic gears. yes you can ruin a gear train, just use a light touch. you can see the gear change color as you buff the gears. move the brush to drive the gears in both directions. either use a top plate clip or keep your finger on the idelr gear, or it will launch and you will never, ever, ever find it. except when your looking for something else you drop, when you no longer care about the idler gear. 

take the top plate off, and use the wire brush on the cluster gear (gently) under the top plate. b4 you put the chassis back together, buff the crown gear (on the axle) the same way. 

it sounds more complicated that it is. once you get the hang of it, it only takes a couple of minutes tops. 

if you try it, less is more. you can also lap the gears more if you want, but once you lap too much those gears are done. 

brasso/toothpaste works too, but takes a long time, and is messy!!!


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## rodstrguy (Feb 14, 2002)

I use comet cleanser mixed into a paste by adding water. works on brass and plastic... when the paste changes color you know you are on the right track...


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## resinmonger (Mar 5, 2008)

If you use toothpaste, you can post them on ebay in twenty years and legitimately claim that they are 

*MINTY!!!!!!!!!!!!!!*

I'm just saying... :freak:


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## jeremy1082 (Apr 27, 2004)

Some of the Auto World chassis are brutal. I just bought 2 new cars (2010 Camaro and 1965 VW bus). One ran great out of the box and the other sounded like a blender full of marbles. I pulled it apart and found the center idler gear to be crappy. I replaced it with an original AFX gear and it ran great.


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## dlw (Aug 17, 1999)

Sometimes you get a chassis with bad gear mesh. This can usually be fixed with placing a downward warp on the gear plate clamp, which will hold the center gear and top plate better. Another thing to check is the rivet holding the rear cluster gear. Sometimes it's too loose and needs some gentle tapping with a small hammer or punch to 'tighten' up the fit and reduce slack.


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## Bill Hall (Jan 6, 2007)

*The grit factor...no right or wrong*

Not to overly generalize or belabor the idea; but I'm gonna anyway...snicker!

Surveys at Model Motoring indicate that it REALLY doesnt matter what you use, but that it matters that you DO use it....whatever it may be.

Things I've used include darn near any fine abrasive within arms reach and some form of liquid to transport it with: Mothers mag polish, automotive rubbing compound, ash from Mt. St. Helens and fresh glacier water, fine valve gringing compound, brasso, comet and oil slurry, comet and water slurry, toothpaste and oil, tooth paste and water, gin and tonic with diatomaceous earth from yer fish filter and a lime twist... but only during certain planetary alignments. :tongue: 

Let's just stipulate that I have experimented and I did inhale. I get great results just whacking the running metal gearsets with some 600 grit paper and oil....then following with some 1200 grit and oil. The ensuing spooge of oil and grit from the paper make a dandy lapping slurry/rouge. Deburs the boogers and laps teeth all in one step. For plastic gearsets the toothpaste is convenient. Wither way it is important to work BOTH sides of any gearset and the sandpaper/slurry method for metal gear sets accomplishes this IMHO. I tend to be more careful with plastic sets and let the tooth paste do it's work...boogering a tooth or teeth is easy, as Mike King indicated. 

Regardless, brass and copper are soft. Casual observation under minimum magnification will show that even if you polish your gear teeth to Hubble telescope specifications (well then again maybe not); after some run time they will become scarified back to somewhere around 600 to 1200...call it 800. Unless of course your running in a Nasa clean room. This also applys to the comm surface... even more so...buff it up to show car standards and after breakin it'll be about...

800 give er take a coupla hun.

Many engineers and builders give creadance to the idea that overly smooth surfaces dont retain oil film correctly and are detrimental to proper lubrication.

Now where's that G&T with lime...I need to go lap and polish some brain cells...:freak:


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## smalltime (Jun 3, 2006)

I've been wanting to say this for years..........

Hey Bill!
Let's go inhale together.
Know any hot women?:thumbsup:


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## AfxToo (Aug 29, 2003)

Bill the Inhaler, you forgot cremains mixed into a slurry with victory circle tears of joy. Look for ones that have a proven racing lineage.

Eye of Newt would be my second choice.


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## A/FX Nut (May 28, 2004)

I've seen this topic before and now I've done something about it. I took a Johnny Lightning jewel case lid and super glued two post in it mount a chassis. 

Used toothpaste with water and have done 4 cars. 2 Aurora T-Jet 500's and 1 AW T-Jet 500, and 1 AW T-Jet 500 Ultra-G.

Cleaned all 4 when done and reoiled and the AW cars are much faster. The Aurora T-Jets, well one is about the same and one is slower.

I'm going to try Brasso for the Aurora T-Jets next. Not happy at all with the results of the Original Aurora Cars.

I ran them for 20 to 30 minutes each direction.

Randy.


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## shipsgunner (Sep 6, 2008)

Thanks Bill... In the words of our IT department at work...

"we're not happy til you're not happy"

Cheers on the G&T w/lime

Dan


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