Torque Tube Shims

[FNFAL]

Stripping the front umbrella gears. Seen some folks have shimmed the umbrella gears in the TTs. Where to buy the shims?

[UFOking]

Here for example: http://www.miracle-mart.com/store/in...oducts_id=4800

[FNFAL]

Thanks, just what I was looking for. Wish I could find a domestic seller. When I search for "Tarot" I get a lot of junk fortune telling sites - strange to name a product line after such a cabalistic practice.

I also have some 10mm OD shims from a previous build I might try and use between the bearings in-lieu of those 6mm ID under the gear.

[Bendero]

I got mine from amain hobbies, they were for rc car diff shimming, same idea. Think I just typed the dimensions and shim in search box and they came up. Or maybe I search for a few hours, I forget

[UFOking]

Before I bought these shims, I used an old bearing that goes onto the umbrella gear, cut it apart, took out the inner part, cut it in half, sand it a bit till I got the right thickness and done.

[FNFAL]

Thanks both. You guys did some work

Originally Posted by UFOking

Before I bought these shims, I used an old bearing that goes onto the umbrella gear, cut it apart, took out the inner part, cut it in half, sand it a bit till I got the right thickness and done.

[lcc014]

Originally Posted by FNFAL

Stripping the front umbrella gears. Seen some folks have shimmed the umbrella gears in the TTs. Where to buy the shims?

Why putting shim to front umbrella gears in the TT ?

[FNFAL]

Due to manufacturing tolerances, there may be more backlash (i.e. poorer gear meshing) between bevel gears than preferred. This can be of issue especially if higher power applications or more abusive tail movements are used, therefore causing teeth to jump and then in time even strip.

Shimming either/both gears can get the gear faces in better alignment. But if I were to do it all over again, me thinks I would go for a belt drive for at least the tail, as those bevels are the most prone to overloading.

But I'm hoping a move to the newer black gears and a tighter mesh will solve my problem.

Originally Posted by lcc014

Why putting shim to front umbrella gears in the TT ?

[lcc014]

Originally Posted by FNFAL

Due to manufacturing tolerances, there may be more backlash (i.e. poorer gear meshing) between bevel gears than preferred. This can be of issue especially if higher power applications or more abusive tail movements are used, therefore causing teeth to jump and then in time even strip.

Shimming either/both gears can get the gear faces in better alignment. But if I were to do it all over again, me thinks I would go for a belt drive for at least the tail, as those bevels are the most prone to overloading.

But I'm hoping a move to the newer black gears and a tighter mesh will solve my problem.

Thanks for the explanation. Do you use black gears in both front and rear ? I tried to use black gears in front of TT and kept white gears in rear of TT. The end result was no good. Tail hit grass when landing and stripped from black gears immediately. Rear white gears had no problem at all.
Then I replaced stripped front black gears with original white gears and had another grass touching during landing. Front white gears were fine with just a very tiny damage to the gear. I flew my heli on Sunday with the very tiny damage front white gear, no problem at all.

[FNFAL]

I agree with your observation about black gear vs white gear. I too had black fail b/4 white in an assembly containing both on my 550 when the tail bearings seized. I so much want to believe the hype, so I will give black one more try. Being the black is more brittle, it may be more fragile in the colder temps. But with summer here, I hope it will be a non-issue.

[lcc014]

Originally Posted by FNFAL

I agree with your observation about black gear vs white gear. I too had black fail b/4 white in an assembly containing both on my 550 when the tail bearings seized. I so much want to believe the hype, so I will give black one more try.

I see....

[ERRATIC]

Originally Posted by FNFAL

Wish I could find a domestic seller.

http://www.valuehobby.com/helicopter...er-tl2365.html



Steve

[FNFAL]

Will order today.

Ended up adding 3x (0.1mm) shims to the umbrella gear. Could have added more, but the out-of-round bevel gear on the vertical shaft caused binding in one spot. Also upgraded the bearings.

Originally Posted by ERRATIC BIRD

http://www.valuehobby.com/helicopter...er-tl2365.html



Steve

[UFOking]

Originally Posted by FNFAL

Will order today.

Ended up adding 3x (0.1mm) shims to the umbrella gear. Could have added more, but the out-of-round bevel gear on the vertical shaft caused binding in one spot. Also upgraded the bearings.

Hi,

where did you buy these bearings?

Thanks!

[FNFAL]

Unfortunately, there's only one major player in the hobby bearing market (hint, hint! - anyone want to give'em a little competition?) and that's Boca Bearing.

http://www.bocabearings.com/

Good service , good selection, but some items can be a little pricey.

I like to use the ABEC 7 ceramic hybird non-contact orange seal with AF2 oil for most non-motor full rotation applications. But really any ABEC 5 or even 3 are better than stock (which usually are ABEC 1 unless you have a Goblin or something). ABEC rating doesn't tell the whole story, but it does let you know the level of matched components. Sure we're only talking about fractions of in-oz of drag torque but just the drive train alone in the 450 uses 16 bearings.

Bearings ABEC 3 VS ABEC 7 (1 min 18 sec)

Originally Posted by UFOking

Hi,

where did you buy these bearings?

Thanks!

[RedOctobyr]

Also consider AvidRC.com. $1 each for their bearings, I've been buying stuff from them for several years, I've been happy.

Sent using Tapatalk.

[Steve Joblin]

Originally Posted by FNFAL

Thanks, just what I was looking for. Wish I could find a domestic seller. When I search for "Tarot" I get a lot of junk fortune telling sites - strange to name a product line after such a cabalistic practice.

The two big Tarot players in the US are Tarot-RC-Heli.com and ClubHeli.com... both are very reputable!

[Bladecpnitro]

Originally Posted by FNFAL

Thanks, just what I was looking for. Wish I could find a domestic seller. When I search for "Tarot" I get a lot of junk fortune telling sites - strange to name a product line after such a cabalistic practice.

I also have some 10mm OD shims from a previous build I might try and use between the bearings in-lieu of those 6mm ID under the gear.

Hey FNFAL, what is the exact size of the shim that fits the TT?
Im gonna need some. I've been a 450 Pro belt guy for 3550 flights and I'm sick and tired of it slipping. A belt survives 99.999% of crashes but I simply can't make it hold. Unless my tail servo is slowly dying and acting up now and then.

I've got my TT conversion done, still working out some bugs and vibes but its obvious that I'm going to need to shim the unbrella gears.

Wouldn't it be nice if folks would send you about 10 of those with your umbrella gears even if you had to pay a buck more? They know your gonna need them.
That's like feathering shaft shims you can hardly find them anywhere.

[FNFAL]

I don't recall exact dimensions - as I don't have any examples here any more. But they work nicely under the umbrella. Looks like Value does not sell these shims any more. Shucks. Linky no worky. In fact I don't see them offered now anywhere.

Something about 0.1mm thick is good (can used multiples). And if you choose under the umbrella, then a 6mm ID with perhaps say a 8mm OD.

Or if you shim in-between bearing stack, then say a 8x10x0.1mm

I think Amain might have something close.

[alyon187]

Tmkrc.com has tt shims for the pro