# TJET Chassis letters and numbers



## mr_aurora (Oct 18, 2005)

I sell a lot of N.O.S. Tjet chassis. It always amazes me how people spin the back wheels and examine the numbers and letters on the chassis bottom and top plates. Some tell me the numbers are better, lower rather than higher. Some tell me the opposite. Some tell me letters are the best. I know why the letters and numbers are there, to identify the many mold cavities used in their manufacture. I know about solid rivet vs hollow rivet, I feel solid rivet were made in the USA by machinists and moldmakers where tight tolerances were a must. The hollow rivet chassis were mass produced in the Orient and tolerances are less stringent. *My question is this, what number/letter chassis do you like, and WHY???*


----------



## Paul R (Nov 3, 2009)

I prefer the closed rivet chassis over the open rivet chassis and the top plates with the square idler gear post over the ones with the rounded post. I don't sort based on the mold number/letter.


----------



## Hotrodzz3 (Apr 5, 2011)

Paul R said:


> I prefer the closed rivet chassis over the open rivet chassis and the top plates with the square idler gear post over the ones with the rounded post. I don't sort based on the mold number/letter.


I've never seen a top plate with a square idler post, how about a picture of one.


----------



## Rich Dumas (Sep 3, 2008)

The post itself is not square, but some of the idler posts are chamfered and those are referred to as rounded posts. The ones that are not chamfered are referred to as squared posts, maybe we should refer to them as non-chamfered posts to avoid confusion.


----------



## Dragula (Jun 27, 2003)

10 or 1 chassis.h or g plate for me.


----------



## Hotrodzz3 (Apr 5, 2011)

OK, I get it now thanks for the explanation....


----------



## honda27 (Apr 17, 2008)

*tjet letters*

I prefer H CHASSIE OR PLATE OR G CHASSIE AND G PLATE. and number chassis 1,2,3,5,6,7,8,9,10. no number 4,s.


----------



## Bubba 123 (Sep 10, 2010)

honda27 said:


> I prefer H CHASSIE OR PLATE OR G CHASSIE AND G PLATE. and number chassis 1,2,3,5,6,7,8,9,10. no number 4,s.


:freak:
I just add a drop of lubricant here, there & test w/ 9V battery....
"IF" it runs w/ out "SCREECHING" w/ in the 1st few seconds....Fine-By-Me :thumbsup:

have come across NOS's that turned over by hand, but Did-Not run...
usually just the simple brushes/commutator issues, ..but "Some" had "Dead" Arms......

my "Theory" ; IF it works "OK" NOW, it should work even better with a cleaning/lube job ... these are around 50 yrs. old now... :drunk:

I'm just glad 2 have some ... lol :thumbsup:

Bubba 123 (happily - senile, in slot car world ) :wave:


----------



## Rich Dumas (Sep 3, 2008)

Newer T-Jet chassis tend to have oversized axle, armature shaft and cluster gear shaft holes, that is because the tooling was shot by the time Aurora switched over to the A/FX chassis. Those chassis work a lot better if you close up the holes.
Another issue is gear plate to base chassis alignment, if they are out of alignment the car will not run properly for several reasons. For one thing the armature will be slightly tilted, another problem is that the gear mesh will not be perfect. If the gear plate is too far back the mesh between the armature pinion and the idler gear will be too tight. If the gear plate is either too far forward or too far back the drive pinion will not be aligned with the crown gear, the cluster gear shaft will be tilted and the driven gear may not mesh as well with the idler gear.
If you have a car that stops on a dime, even though you run without brakes, this type of misalignment is likely to be part of the problem.


----------



## hojoe (Dec 1, 2004)

I pay no attention to the letters and numbers. If it runs good, great. If it doesn't I work one it till it does. Tuning is half the fun.
hojoe


----------



## mr_aurora (Oct 18, 2005)

Good comments from all. On the letters, I think I have seen up to I, anyone seen J or K or L? On the numbers, 1 thru 10, anyone seen 11 or 12? Just asking.. Could be the letters were steel molds made in the US and numbers were molds made in the Orient? Bob


----------



## slotking (May 27, 2008)

Good comments from all. On the letters, I think I have seen up to I, anyone seen J or K or L? On the numbers, 1 thru 10, anyone seen 11 or 12? Just asking.. Could be the letters were steel molds made in the US and numbers were molds made in the Orient? Bob

I know I have 13 & 14, can not remember if I saw 15.
I have seen L as well


----------



## rholmesr (Oct 8, 2010)

I have only seen up thru letter i as well. I have seen chassis number 14, but do not recall ever seeing 11 thru 13. I prefer solid rivet chassis and of those i like the blank ones the best (no letter or number). I have found that a lightly used solid rivet chassis requires little if any peening of holes for optimal fit. Top plates e f g and h are best for me. They seem to generally be square and fit into the chassis well without excess slop or binding and they have the square idler post for best fit up of the idler gear to post.


----------



## mr_aurora (Oct 18, 2005)

Top plates e f g and h are best for me. is what Rholmesr said. I know that tjet bodies were made in (4) cavities per mold. If I go on the theory that the chassis were also, I think A,B,C,D were in one mold and E,F,G,H were in another and they have the squared off idler post. Makes some sense. Top plates would be in the same mold with corresponding letters/numbers. Wow, cool......


----------



## Dragula (Jun 27, 2003)

if you can find them,the oddball h4 chassis and h3 which were usually tuff ones chassis but some had copper electrics,these are fantasticly square and true.
Christian


----------



## Grandcheapskate (Jan 5, 2006)

Rich Dumas said:


> Newer T-Jet chassis tend to have oversized axle, armature shaft and cluster gear shaft holes, that is because the tooling was shot by the time Aurora switched over to the A/FX chassis.


 By which production years would you say the tooling was "worn out"? As you (may) know, cases of T-Jets chassis had the date printed on the outside of the box. I think mine are 1969 and 1970. So if I ever had the time, it would be interesting to check the chassis based on date.


Thanks...Joe


----------



## Rich Dumas (Sep 3, 2008)

All of the NOS T-Jet rolling chassis that I have bought had loose holes. I have no idea of when those chassis were actually manufactured, but it seems logical that the older chassis were used to build complete cars. If I understand it correctly the chassis were made in Hong Kong and the bodies were made in the US. When Aurora folded up they were still stuck with several trailer loads of rolling chassis and people were abe to buy those for a song.


----------



## honda27 (Apr 17, 2008)

*chassies*

I have seen a few with the letter N on them some with j k l on them some with 11 12 13 14 on them.


----------



## LDThomas (Nov 30, 1999)

No.11 chassis are special. They have ribs molded in the magnet cavity to keep the magnets centered. A feature not seen in other chassis. This is why No.11 chassis are popular in strictly stock classes that do not allow shimming the magnets.


----------



## rholmesr (Oct 8, 2010)

Good info on the 11 chassis. I need to go thru the parts pile when i get the chance!


----------



## tjetracer (Mar 20, 2003)

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.


----------

