# t-jet crown gear questions



## joegri (Feb 13, 2008)

i,m kinda stuck on a few builds and crown gears are holdin me up. round here (my trak) tjets go best with a 12 tooth drive cluster gear.now i,m out of the crown that work/fit best. after searching for some new ones i see they are very expensive like 6.50 per then add 6.00 for shipping. it starts to add up quick plus i,m cheap . is it adviseable to grind down the shoulder off of a different crown and make it fit? or save pennies and move to another project.i really strive for the best gear mesh possible and it really does make a difference.


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## bearsox (Apr 22, 2006)

*Tjet Crown gear questions*

*Joe ,
i can understand where your coming from if you wanted to order a single gear and figured that it would cost you $13.50 for it when adding your total. So not knowing the product or not needing alot of the product would deter you from that purchase. Is there not a local guy who happens to have what you need or a local vendor that can help ? I am working on a NEW crown now but is still a few weeks away. Close but still not yet ready. New material with a new cut and new price ( yes less cost Joe LOL ) but assuming you want something now ....there are some good options. Ya just gotta find that local guy to save on shipping i'm guessing to satisfy your cost issue ? If you are in a pinch i can sell ya some private stock CNC stuff cheaper off list with some cheap ole $2.00 shipping ? Just send me an email and i will let ya know what i can come up with.

Bear :wave:*


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## Boosted-Z71 (Nov 26, 2007)

Bear I am in the same spot, we do not have a local hobby shop around here within 60-70 miles that has anything for an HO scale, Hobby Lobby occasionally has complete cars, everything I need I have to order. If you have a site or list of parts I would gladly send my business your way to support a fellow HT member. In the past I have bought everything either on-line or e-bay, most have not been great deals & I have had trouble finding some of the better quality t-jet fray style parts for a fair price.

Thanks

Boosted


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## TK Solver (Mar 18, 2004)

Not sure why the shipping would exceed the price of a stamp... A crown gear isn't that thick that it wouldn't fit in a standard envelope. Plus, with gas at current prices, getting one from a "local" dealer would exceed the price of that stamp a few times over.


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## bearsox (Apr 22, 2006)

*tjet crown gear questions*



TK Solver said:


> Not sure why the shipping would exceed the price of a stamp... A crown gear isn't that thick that it wouldn't fit in a standard envelope. Plus, with gas at current prices, getting one from a "local" dealer would exceed the price of that stamp a few times over.


If they were sent in a standard envelope the envelope would be sent through the sorter and either the crown would crush via machine or could force the envelope to tear . Too risky in the end . Perhaps a padded version would work if you request a hand sort . I just buy indestructo brand boxes or recycle other decent boxes to cut costs so most shipping is in the $2-2.50 range unless it's alot or heavier items. I do see why some go the other route don't get me wrong as it has less hassle dealing with boxes and time doing priority etc. On the local dealer ...... i suppose it would be smart to wait to head to the shop till you had a few items to purchase or grab your goodies on a race night ? 

Bear :wave:


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## bearsox (Apr 22, 2006)

*tjet crown gear questions*



Boosted-Z71 said:


> Bear I am in the same spot, we do not have a local hobby shop around here within 60-70 miles that has anything for an HO scale, Hobby Lobby occasionally has complete cars, everything I need I have to order. If you have a site or list of parts I would gladly send my business your way to support a fellow HT member. In the past I have bought everything either on-line or e-bay, most have not been great deals & I have had trouble finding some of the better quality t-jet fray style parts for a fair price.
> 
> Thanks
> 
> Boosted


*Contact me off list via email [email protected] and i will see what i can do to help ya out .

Bear :wave:*


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## Boosted-Z71 (Nov 26, 2007)

Thanks Bear, I will try to get a list together here in a day or so and get with you.

Boosted


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## RT-HO (May 27, 2009)

Hello,

There may be an injection molded version of the RT-HO crown gears down the road.
I've been cutting them with CNC for a few years now and the design is a proven performer.
If you order an RJ-Jet with 12 tooth drive pinion it will have an RT-HO crown.
I tried several versions of the design before I was happy with it.

I recently bought a pneumatic powered injection molding machine.
If I ever get ahead producing parts & tools I plan to machine some molds.
T-Jet Gear plate and crown gear molds are at the top of the list.

An injection molded crown gear will be MUCH MUCH cheaper to produce.
I don't know if I can pull it off. Wish me luck !

Rick


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## alpink (Aug 22, 2010)

wishing Rick luck. so far all of his products that I have obtained are well worth the costs.


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## alpink (Aug 22, 2010)

oh yeah, t-jet crowns can easily be cut on the shoulder with a nice sharp hobby knife and the gear mounted on an axle, spinning in a motor tool. of course you take off only a little at a time until you have the desired fit. measuring a crown that already suits your purpose will take a good deal of the guess work out too. I have successfully trimmed a number of t-jet gears for numerous purposes.


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## joegri (Feb 13, 2008)

wow what great feedback from all you guyz.for my pal bear i,ll get with ya for an order cuz i need axels too!! seems boosted and i are in the same island nobody around me plays with the lil cars so i count on you guys for tips and hints.and rick at rt-ho i have baught a gear pak and 3 crowns that work very nice!and will buy more when the carpenter world pics up. but best of all i just shaved down a crown that seems to work for now.thanx all for yer input. seems silly but i enjoy passing the evening by tinkering and listening to the xm satelite tunes and tryin to get these lil cars to get! thanx guys


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## clemedc (Feb 2, 2011)

I have the same problem here, no local or nearby hobby shop. But I have dealt with bearsox a couple times now and I can say he is a TOP NOTCH GUY to deal with.


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## Dyno Dom (May 26, 2007)

Are the rear axle diameters the same for AW/JL & Aurora T-Jet? 
The axle size of Tomy are .063", the T-jet seem to be a bit thicker @ .070".


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## bearsox (Apr 22, 2006)

*Tjet Crown gear questions*



Dyno Dom said:


> Are the rear axle diameters the same for AW/JL & Aurora T-Jet?
> The axle size of Tomy are .063", the T-jet seem to be a bit thicker @ .070".


Hi Dom ,
yes AW/JL and TJET axles all work the same in the rear. For the most part size range is .0625-.0635 with ranges on occasion up to a robust .0650 ( to much for my liking ) . Axles can be from other cars as you point out like Tomy .063's and old Aurora truck axles . Or you can cut your own from Drill blanks , Drill rod , Music wire etc . Places like www.cencogrinding.com sells drill rod and blanks in sizes you can cut to length and use via dremel . www.Smallpartsinc.com sells music wire in sizes you can cut and use cheaply for most tjets and AW etc cars. Hope this info helps ya out.

Bear :wave:


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## alpink (Aug 22, 2010)

don't forget McMaster-Carr http://www.mcmaster.com/#drill-rods/=bli7aw


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## bearsox (Apr 22, 2006)

*tjet crown gear questions*



alpink said:


> don't forget McMaster-Carr http://www.mcmaster.com/#drill-rods/=bli7aw


Thanks Al Pink ( hope your digging the colorful post ) LOL ! I did forget for a moment and likely a couple more too that i have used along the line. McMaster has loads of cool stuff for the creative slotter .

Bear :wave:


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## alpink (Aug 22, 2010)

always like pink. heck aeroSmith even wrote a song in my honor! LOL


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## wheelszk (Jul 8, 2006)

not!!!!!!!!!!!!!!!!!!!!


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## Dyno Dom (May 26, 2007)

Thanks Al & Bear, good info. Are you using the smaller diameter drill blank
only with new crown gears? If an AW/JL rear axle is #50 gauge, about
.0690-.070, wouldn't a gear taken off the larger axle & installed on a smaller
diameter drill blank spin?


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## clemedc (Feb 2, 2011)

.0635 = #52 drill


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## Dyno Dom (May 26, 2007)

Clem,???  Tomy axles are .063, aren't the AW/JL larger??


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## clemedc (Feb 2, 2011)

Well Dyno the JL I have arent knurled at the ends the same as the old t-jets 
JL axles are .060 
Aurora T-jet are .062 the same as Tomy/AFX G+
Those are 2 I just compared Im sure if you checked a batch of either it would vary.
But I believe where the real concern lies is in the knurling on each axle but since we are working with plastic gears on steel axles and we have LOCTITE whats a few thousandths among friends


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## clemedc (Feb 2, 2011)

clemedc said:


> Well Dyno the JL I have arent knurled at the ends the same as the old t-jets
> JL axles are .060
> Aurora T-jet are .062 the same as Tomy/AFX G+
> Those are 2 I just compared Im sure if you checked a batch of either it would vary.
> But I believe where the real concern lies is in the knurling on each axle but since we are working with plastic gears on steel axles and we have LOCTITE whats a few thousandths among friends


Well I guess were actually talking a few HUNDRED THOUSANDTH


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## bearsox (Apr 22, 2006)

*tjet crown questions*



clemedc said:


> .0635 = #52 drill


*That's what you are looking for ! A #52 will do ya right for tjets just fine . Music wire at Small parts inc comes in .062 and .064 and will works as well but generally you may need to do some clean up . Cost is usually less so it's an offset time cleaning VS savings. 

Bear:wave:*


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## slotking (May 27, 2008)

> steel axles and we have LOCTITE whats a few thousandths among friends



whole lot when it come to gears and hubs staying on


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## clemedc (Feb 2, 2011)

the main problem usually lies in careless installation and or trying to reinstall the same gear/hub several times thus wearing out the gear and or hub. YOU AINT WEARING OUT THE AXLE WITH THOSE PLASTIC GEARS!


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## slotking (May 27, 2008)

right but once you have a good gear mesh, and axle setup, if an axle is bent or other issue, you want the same size or bigger if the axle hole gets bigger, or the gear hole.

just that axle size does matters a lot.


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## clemedc (Feb 2, 2011)

yes there are many things to check and keep an eye on. i have had new wheels that went on new axles crooked it seemed as if the hole wasnt straight. but again if your axle is knurled like stock t-jet axles the knurl is larger than the axle the axle measures .062 but the knurl which holds the gear is larger than the axle and eats at the gear when installed, always watch the knurl on the axle. but on the other hand if you use drill blanks there is no knurl and they will be straight, the chances of a bent drill blank are slim to none.


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## slotking (May 27, 2008)

> i have had new wheels that went on new axles crooked it seemed as if the hole wasnt straight.


taper the ends of the axle.
the flat edge of an axle can hit and dig into the side of the hub, this is a problem of course. the with flat edge removed, the axle will follow the hole


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## clemedc (Feb 2, 2011)

*taper*



slotking said:


> taper the ends of the axle.
> the flat edge of an axle can hit and dig into the side of the hub, this is a problem of course. the with flat edge removed, the axle will follow the hole


yes i`ll have to start doing that :thumbsup:


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