# Tjet Chassis and Gear Plate Info (lost..)



## yellerstang (Feb 20, 2012)

Hey all,

A few years ago, maybe 5 or more, there was some very detailed and close up pics of what people liked at the time for chassis and gear plate selection. It showed very detailed pics of the armature hole in the chassis, along with numbers and data that was preferable in building tjets.

By chance, does anyone know who did this or where it may have gone to? I know there are internet archives out there, but finding some of this stuff is near impossible.

At one point, I had all of this information printed out on paper, but that is gone too.....

Thanks

Jess


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## Ralphthe3rd (Feb 24, 2011)

I saved the following info, which may help you ?

There are magnet cavity ribs on some 1-3 and 13 too. I know there are others too. Axles holes on the later numbers 11-14 are tight. Haven't seen them loose. The holes are oversize on 1-4 and need to be tightened on those. Number 11 is the only chassis that I know of where the holes are too tight for an .0635 axle and sometimes even a stock axle. Number font on chassis 1-4 is identical, 5 and 6 are the same and 7-14 are the same. Not sure how 5 and 6 would be on a mold as I haven't seen any two numbers like them. 5 and 6 are longer more spacious chassis. Chassis fonts 1-4 are the same, 5 and 6 are the same and 7-10 are the same. 1-6 are rounded post while 7-10 and A-H and H? are square. As for building chassis the truck chassis were always considered the best. These were the later run chassis. Most cases showing 69 and 70. Chassis are straight and the gearplates have the square posts. Lighted chassis were good too but often had the magnet nubs in the chassis. Rounded post gearplates were more on the standard and earlier chassis and these tended to be warped more often than not. They always warp in the same direction also. The only chassis with molding defects that I know of is the #3 and #4 chassis. #4 chassis has one hole in the LWB position off which throws the stance way off. That is only for open rivet cars. Closed rivet #4 chassis are good. Gearplates 1-6 usually have the spacer pad off from the hole. Since it is different from gearplate to gearplate it was either drilled off or, Bob mentioned, perhaps one or more of the molds were off. This would only apply if all the gearplates in the mold were numbered the same. E chassis also has the arm spacer pad off but the hole is always in the same place and in the proper position. Just the pad is off. There are other differences chassis to chassis like magnet centering, magnet tightness, hole distances, lengths, etc. The chassis are more different than most admit but finding a match between chassis and plate is the most important factor when building a good car. My observations are for open rivet cars. Never had the opportunity to open a case of closed rivet cars.


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## yellerstang (Feb 20, 2012)

Wow, thats a lot to digest! Thanks so much.


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## slotking (May 27, 2008)

yes it is
but even the certain number chassis are not all the same.

I think it is best to test each part. with the chassis check that the axle holes allow the car to sit flat. check that the rivets for the the electrics are tight.
make sure the axles move freely.
make sure you have good brush tension. 

place the gear plate on the chassis and verify that the holes line up and that the plate sits flat and does not rock.

make sure the clip does not allow to much movement.

but even after all that, you can have a handful of identical chassis that will will handle differently, and have different speeds.

bottom line is to test, test, test


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## yellerstang (Feb 20, 2012)

I often wondered how many of a chassis may have the same number but actually be made in a different mold.

Testing is the best. I tend to look at the quality of the parts, then swap gear plate after gear plate until I get one that is really loose, then go from there.

I have done all of the other stuff, start from scratch, test, fit, wiggle, pinch, whatever... but test and runs seems to work out for me.

Im not racing at a Fray or Echorr type situation, so its ok for me. I have been getting more and more into stock Tjet drag racing, it all applies there. The thing with tjets, we all know, they can be blistering fast once-and then never again....


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## yellerstang (Feb 20, 2012)

The pics that were in the website years ago gave very specific close up shots of the key areas of friction, the whys and hows were shown. I sure would like to have that data again...

I did print it out, but lost it somewhere in the past...


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## slotking (May 27, 2008)

> I often wondered how many of a chassis may have the same number but actually be made in a different mold.


a couple of thing can affect the chassis.

the mold may really be a mold with that will create say 8 chassis.
the plastic on the 2 ends will cool down faster than the 2 in the middle.

That may affect how flat the chassis is.
(told to me by a guy who did back in the day for a living)


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## slotking (May 27, 2008)

> The pics that were in the website years ago gave very specific close up shots of the key areas of friction, the whys and hows were shown. I sure would like to have that data again...


there are some out there.

Beside the video library I setup, I am trying to collect articles as well.
I have a few, but would like more.


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## Rich Dumas (Sep 3, 2008)

The mould can produce a number of chassis in one cycle, the numbers or letters on the chassis indicate which location in the mould was used. To shorten the cycle time the mould is cooled with water, possibly the cooling would be uneven resulting in warped chassis or ones that have stresses that might result in the chassis warping later on. One reason for boiling a chassis and letting it cool slowly is to remove those stresses.


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## yellerstang (Feb 20, 2012)

My dad and I used to fly rc planes, been in the hobby about 55 years now (like tjets). He used to boil the nylon props so they would not break at high rpm. It took the stress out of the prop, according to him.


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## slotking (May 27, 2008)

> One reason for boiling a chassis and letting it cool slowly is to remove those stresses.


or talk to the chassis sweetly as you lightly rub it.
that will also reduce the stress
:wave:

:jest:


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## yellerstang (Feb 20, 2012)

*Talking sweetly*

My buddy used tp pat the dash on his baby, a 67 Chevelle. You made me laugh a bit at that one. Thanks


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## vickers83 (Mar 8, 2010)

slotking said:


> or talk to the chassis sweetly as you lightly rub it.
> that will also reduce the stress
> :wave:
> 
> LMFAO!!


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## LDThomas (Nov 30, 1999)

slotking said:


> or talk to the chassis sweetly as you lightly rub it.
> that will also reduce the stress
> :wave:
> 
> :jest:


Hmmm... Would have thought that would make it stiff.


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## ajd350 (Sep 18, 2005)

LDThomas said:


> Hmmm... Would have thought that would make it stiff.


Just as long as it doesn't stay that way over four hours.....


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## Bill Hall (Jan 6, 2007)

Contact your physician immediately!


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## alpink (Aug 22, 2010)

call additional partners


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## Rich Dumas (Sep 3, 2008)

The plastic will absorb a small amount of water when you boil it and become a little more flexible. If you bake a chassis it will lose water and become stiffer. Baking or boiling a chassis to modify its flexibility is a common practice with inline magnet car racers. A T-Jet car has relatively weak magnets and they are further from the rails, I am not convinced that the stiffness of a T-Jet chass has much impact on how it handles.


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## yellerstang (Feb 20, 2012)

*Flex*

I agree with the flex, likely less of a concern on lock and joiner tracks like mine.


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## yellerstang (Feb 20, 2012)

Im still hunting for the old info, the site is gone now, but I will keep hunting in the archives. Somewhere, its out there.


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