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Saito2

Thundershot thrust bearing query

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When the Terra Scorcher re-re arrived, it was missing the thrust bearings from the original, instead, opting to use the E1+thrust washer found on the lesser Thundershot series vehicles. Several folks form the forum here replaced the thrust washer assembly with an 1150 non-thrust (radial) bearing. Since an 1150 bearing is not a thrust bearing, what advantage does it provide over the proper thrust washer assembly Tamiya specs? Is it simply to reduce friction upon the spinning shaft it rides on? 

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Curious as well. I’ve bought flanged 1150s, thrust 1150s, and normal 1150s to test, but haven’t gotten there yet…

Terry

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I probably have several hundred RC bearings.  But, I would prefer using washers than a bearing if the mechanism calls for thrust bearings.   

I'm assuming @Saito2 is asking, not because he doesn't know, but because he wants to start a conversation without criticizing?  

679FzDH.jpg

Two bevel gears always want to spread apart.  That's why CC-01 needs thrust washers. (In my case two 850s and 5 shims. This is not ideal as the 1150 bearing is taking force from the side. A 1150 plastic bearing would work better. Not by itself, but with a washer.  The previous owner didn't do this, so you can see the resulting damage on the teeth.)

ZqKloVs.jpg

The force that spreads bevel gears is well demonstrated on Juggernaut 1 gears. Thankfully, Tamiya shipped Juggernaut 2 gears to Jugg 1 owners for free. (And the gear ratio was bad; each tooth was taking too much force, also the bevel gears weren't supported well laterally.)

w4sOCjS.jpg

To prevent this, the shaft has to be supported on top and bottom of the gear. The thrust bearing part has to support it strongly so it wouldn't spread.  That's why a thrust bearing is necessary (below is Bigwig which comes with a thrust bearing.  I bought and installed one on Boomerang too, I think. The previous owner must have lost it, there was a regular 1150 bearing in there). 

RpZc8YS.jpg

Regular bearing isn't designed to be slippery along the shaft.  It could bind.  (It may support the weight, just that it would create more friction.) 

You can hold a 1150 bearing between your index fingers.  You can twist it 90 degrees, using the bearing as the pivoting point.  You can feel that nothing much is turning.  If you had 2 washers, they'll be smoother. Actually, 2 pennies would be smoother than one bearing... It's a figure of speech. Don't put pennies in your gearbox! 

kcjq403.jpg

(sorry, my drawing goes back 30 years if it goes outside of faces

I guess the logic is, "a bearing is better than a washer."  But not where a thrust bearing is needed.  

So, if there isn't a proper thrust bearing, a bunch of loose shims or washers would be better than a single 1150 bearing.  

 

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Having read the above and knowing it makes sense, in 2014 when I rebuilt an original thundershot project, it's still my main runner to this day with 200+ hours using 1150 ball bearings in place of the washers with no issues whatsoever, so I'm the thundershot case and similar models it's not an issue.

my 2005 re-re thundershot i built with the suggested plastic bushing and washer, retired it to the shelf in 2014 (100+ hours), also with no issues........

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7 hours ago, Juggular said:

But, I would prefer using washers than a bearing if the mechanism calls for thrust bearings.   

I'm assuming @Saito2 is asking, not because he doesn't know, but because he wants to start a conversation without criticizing?

At first examination, I too, would prefer using the specified washers over the (non-thrust) bearing, especially considering the prop joint is supported on both ends with bearings. However, in the Terra Scorcher re-re thread, several members, such as @taffer (who are far more knowledgeable about the Thundershot chassis than I) spoke of using the 1150 non-thrust bearing as a substitute. I did not wish to offend or criticize (as @Juggular noted) but rather was genuinely curious about possible advantages of its use by those with long-term experience.

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In the boomerang for example it maybe more critical to use the proper thrust bearings (re-re included them) but for the thundershot chassis you'll be fine (never gone faster than 14t motor though, majority of my hours are (and will continue to be) using Tamiya Super stock 23t

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11 hours ago, Saito2 said:

I did not wish to offend or criticize (as @Juggular noted) but rather was genuinely curious about possible advantages

Sometimes I wonder if you might be neurotypical because it takes good understanding of social circumstances and nuances of words to be tactful and diplomatic. Being tactful is a good quality. 

 

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2 hours ago, Juggular said:

Sometimes I wonder if you might be neurotypical because it takes good understanding of social circumstances and nuances of words to be tactful and diplomatic. Being tactful is a good quality. 

Thank you for the complement. Years of studying others is the secret. To be honest, most of my language is very very calculated. Decades ago, I was blunt and terse with my questions which offended people. It wasn't my intention but it came across that way. I respect others and value knowledgeable input so I practiced being more diplomatic. I figure its one of the instances where Data (for Star Trek lovers) or the Vision (for comic book lovers) have more humanity than the real thing at times, because they study and attempt to emulate it through understanding it. If studying others hadn't been a "special interest" of mine I might stick out like a sore thumb (and blending quietly into the background has always been key to my survival).

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3 hours ago, Saito2 said:

Years of studying others is the secret... blending quietly into the background has always been key to my survival

Sounds like Jedi training!  

 

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I did my experiment with the flange, thrust, and standard bearing last night…

The kit E5 and thrust washer total 3.92mm in thickness.

The flange bearing I bought was too thick (5mm) so that was out.

The thrust bearing is 3.92mm thick, but the bevel gear rides on the center metal part of the thrust bearing rendering this type of bearing useless.

Indeed, the std bearing (4mm thick) works best. The bevel gear is designed to ride the inner metal part, and the Ax parts are designed to support this type of bearing by supporting the outer metal part.

Terry

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On 7/8/2021 at 2:18 AM, Juggular said:

I probably have several hundred RC bearings.  But, I would prefer using washers than a bearing if the mechanism calls for thrust bearings.   

I'm assuming @Saito2 is asking, not because he doesn't know, but because he wants to start a conversation without criticizing?  

679FzDH.jpg

Two bevel gears always want to spread apart.  That's why CC-01 needs thrust washers. (In my case two 850s and 5 shims. This is not ideal as the 1150 bearing is taking force from the side. A 1150 plastic bearing would work better. Not by itself, but with a washer.  The previous owner didn't do this, so you can see the resulting damage on the teeth.)

ZqKloVs.jpg

The force that spreads bevel gears is well demonstrated on Juggernaut 1 gears. Thankfully, Tamiya shipped Juggernaut 2 gears to Jugg 1 owners for free. (And the gear ratio was bad; each tooth was taking too much force, also the bevel gears weren't supported well laterally.)

w4sOCjS.jpg

To prevent this, the shaft has to be supported on top and bottom of the gear. The thrust bearing part has to support it strongly so it wouldn't spread.  That's why a thrust bearing is necessary (below is Bigwig which comes with a thrust bearing.  I bought and installed one on Boomerang too, I think. The previous owner must have lost it, there was a regular 1150 bearing in there). 

RpZc8YS.jpg

Regular bearing isn't designed to be slippery along the shaft.  It could bind.  (It may support the weight, just that it would create more friction.) 

You can hold a 1150 bearing between your index fingers.  You can twist it 90 degrees, using the bearing as the pivoting point.  You can feel that nothing much is turning.  If you had 2 washers, they'll be smoother. Actually, 2 pennies would be smoother than one bearing... It's a figure of speech. Don't put pennies in your gearbox! 

kcjq403.jpg

(sorry, my drawing goes back 30 years if it goes outside of faces

I guess the logic is, "a bearing is better than a washer."  But not where a thrust bearing is needed.  

So, if there isn't a proper thrust bearing, a bunch of loose shims or washers would be better than a single 1150 bearing.  

 

I see what you mean but isn't your illustration assuming that both the inner and outer race of the bearing are being pressed on simultaneously? On models like the Thundershot, it seems like this isn't the case.

Saying that, though, even if the inner and outer race of the bearing are able to turn independently, the bearing isn't designed for a lateral load and even if it could handle it, I would expect there to be significant lateral flex between the inner and outer race whilst something as simple as a plastic bearing, as you say, will simply not be capable of that level of deformation.

Sometimes simple plastic or metal bearings do just fine. Especially if they are well lubed and buried deep within transmissions away from grit and sand etc. I've taken stuff apart that's been unopened for 30 years and the plastic bearings are still fine if foreign debris haven't found their way in. 

 

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On 7/8/2021 at 8:19 AM, taffer said:

Having read the above and knowing it makes sense, in 2014 when I rebuilt an original thundershot project, it's still my main runner to this day with 200+ hours using 1150 ball bearings in place of the washers with no issues whatsoever, so I'm the thundershot case and similar models it's not an issue.

my 2005 re-re thundershot i built with the suggested plastic bushing and washer, retired it to the shelf in 2014 (100+ hours), also with no issues........

yes here I say both ball bearing and plastic bushing with washer (as per manual) have been fine after many,many hours....if you have one, stick a ball bearing in!

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15 hours ago, rwordenjr said:

The terra scorcher comes with bearings to replace said bushing right?

The original kit had a thrust ball bearing but the rere doesn't

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24 minutes ago, taffer said:

The original kit had a thrust ball bearing but the rere doesn't

It has a bushing or bearing? The rere

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It has a plastic bushing with the washer, just like the other rere's

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It should be noted that if you buy a Fast Eddy bearing kit, the kit does NOT include (3) 1150 bearings (thrust or otherwise) to replace the thrust washer and bushing...

If you read my Dragon thread above, you'll see I ended up using regular 1150 bearings instead of 1150 thrust bearings bc of the way the shaft rotates...

Terry

 

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I don't know of any bearing kits that Inc the 3 extra bearings???

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Very interesting topic, didn’t even know there were options to replace the E1/thrust washer combo.

Thus, I did a little experiment with 5 study groups and 3 outcomes. I took out the entire front gear and twistet the propeller joint to feel the resistance when turning the propeller joint.

Study groups were:

1. E1/thrust washer combo

2. steel ball bearing

3. original Tamiya one piece thrust bearing 53136 5mm x 11 mm x 4 mm

4. three piece thrust bearing 5 mm x 11 mm x 4,5 mm

5. three piece thrust bearing 5 mm x 11 mm x 4 mm (similar to the one that was used as an upgrade in the 80s terra scorcher)

Outcomes were: low resistance, medium resistance and high resistance.

Results:

1. E1/thrust washer combo => low resistance 

2. steel ball bearing => high resistance 

3. original Tamiya one piece thrust bearing 53136 5mm x 11 mm x 4 mm => high resistance (surprising and disappointing since it looks really sexy :-)

4. three piece thrust bearing 5 mm x 11 mm x 4,5 mm => high resistance (not surprising since 0,5 mm too thick)

5. three piece thrust bearing 5 mm x 11 mm x 4 mm => medium resistance (surprising since closest to 80s upgrade)

Conclusion: I will use E1/thrust washer combo only.

Cheers, have a nice weekend!

 

 

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On 9/25/2021 at 3:40 PM, Marc73 said:

Very interesting topic, didn’t even know there were options to replace the E1/thrust washer combo.

Thus, I did a little experiment with 5 study groups and 3 outcomes. I took out the entire front gear and twistet the propeller joint to feel the resistance when turning the propeller joint.

Study groups were:

1. E1/thrust washer combo

2. steel ball bearing

3. original Tamiya one piece thrust bearing 53136 5mm x 11 mm x 4 mm

4. three piece thrust bearing 5 mm x 11 mm x 4,5 mm

5. three piece thrust bearing 5 mm x 11 mm x 4 mm (similar to the one that was used as an upgrade in the 80s terra scorcher)

Outcomes were: low resistance, medium resistance and high resistance.

Results:

1. E1/thrust washer combo => low resistance 

2. steel ball bearing => high resistance 

3. original Tamiya one piece thrust bearing 53136 5mm x 11 mm x 4 mm => high resistance (surprising and disappointing since it looks really sexy :-)

4. three piece thrust bearing 5 mm x 11 mm x 4,5 mm => high resistance (not surprising since 0,5 mm too thick)

5. three piece thrust bearing 5 mm x 11 mm x 4 mm => medium resistance (surprising since closest to 80s upgrade)

Conclusion: I will use E1/thrust washer combo only.

Cheers, have a nice weekend!

 

 

Great testing but I feel like the resistance you mention could be down to the high amount of moulding flash on those bevel gears and using something such as a steel bearing is just making the problem more obvious due to tighter tolerances. 

I recently put a Thunder Dragon together and using a bearing in place of the E1/thrust combo was still pretty smooth apart from one or two tight spots in the rotation which I am very confident are down to the poor moulding. 

I could be totally wrong of course, and you are experiencing a totally different thing but that was my observation. After I spent a while trimming flash off the gears and then set the car with it's wheel off the ground and let it run on low throttle for about 30 minutes, things moved nice and freely even with the bearing in place.

Normally, I would just stick with the thrust setup, even if it's not a proper bearing, as long as the shaft can be supported elsewhere by proper bearings. That's the case with the shaft with the propeller joint on. You can put an 1150 one side and an 850 the other side and then the thrust washer can do it's thing in the middle:

image.png.d939b51d2749c6ba3b7fb46465a68ded.png



But what I don't like is having one end of that output shaft from the gearbox riding solely on the E1 plastic bushing, that's the part I really objected to and what made me decide to use bearings, even though they aren't optimized for axial loads. 

image.png.6b467f78c6225b5f2d256a48f6d1aa23.png

Anyways, in my case, the resistance went away when I worked on the gears a little and then let it run in on low throttle for a while. Everyone has different experiences, though.

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Thank you for your detailed reply, Nowinaminute!

It is totally possible that the results I found in my experiment were due to molding flesh on bevel gears. However, I used my runner that had already a running time of several hours and not a new built gear. Since I don’t know how to remove molding flesh of bevel gears myself and since I have the shaft of the propeller joints on both sides supported by ball bearings, I will stick to the E1/thrust washer combo in both propeller joints front and rear.

image.png.54c71f13b24b494b4959e1e3723fc6a5.png

But, as you pointed out in your post, the third location where the E1/thrust washer combo is used is at the end of the output shaft of the rear gearbox. In this location, the shaft is not supported on both sides by ball bearings. Thus, I repeated my experiment with the rear gearbox by twisting the rear propeller joint and using the above mentioned 5 different setups at the end of the output shaft after tightening the 4 screws of the gearbox cover and thus applying axial pressure.

image.png.295ab0e899b63ca70080cc9d0eaa381e.png

 

This time, the outcome was totally different to the first experiment:

The highest resistance was found using the E1/thrust washer combo and the three piece thrust bearings.

The best options in this location with lowest resistance were the 5x11x4 steel ball bearing and the Tamiya 5x11x4 one piece thrust bearing (53136), with a slight advantage for the one piece thrust bearing.

Based on this, I will use in my Thunder Shot full ball bearings, stick with the E1/thrust washer combo in the front and rear propeller joint and thanks to Nowinaminute now use the sexy looking Tamiya 5x11x4 one piece thrust bearing at the end of the output shaft of the rear gearbox (53136) :-)

image.jpeg.c55c5f28dda546df9aeb7132e0926b30.jpeg

Cheers, Marc

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Not quite on topic - but close….. and it looks like the right people might be on this thread if you don’t mind the hijack….

I’ve just completed a rere thunder dragon, and have very loud clicking from both gear boxes. I’ve traced it to the nylon bevel gears (running the car without the bevel gear cover on and then without the nylon bevel gears….) and shaved and filed the gears in the rear box - which has reduced the noise by about 50% - but it is still noticeable. The front clacks like it’s catching the casing - but again it is the nylon bevel gears and how they mesh. I’ve stripped and rebuilt once already but will have a final go. I’ve built around 25 cars so far without any issue like this (including my original vintage terra scorcher) - so grateful for any other advice - I do recall noticing the bevel gears had lugs on the planes of the gear splines from the moulding process and think I should have shaved those before first assembly. I am also using Tamiya cera grease rather than the standard thicker Tamiya supplied yellow/general purpose stuff for what that’s worth…

Grateful for any advice folks!

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Interestingly, I found a publication from 1987, in which Tamiya recommends a normal ball bearing as an upgrade, so I might follow that recommendation in the future and replace the E1/thrust washer combo at the shafts of the propeller joints front and rear, but stick with the one piece thrust bearing (53136) at the end of the output shaft of the rear gearbox.F95E04D1-A6B3-49B0-A3BC-9410E9CC442F.thumb.jpeg.502c9848562e0d19403482e21120ea84.jpeg

CD1BD29E-3954-4536-8AB0-352CF6790D99.jpeg

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I have mentioned this before in the forum's but alas it gets lost in the sea of information... 

As I said previously for this particular part even the plastic e1 part is good enough after having inspected a buggy years ago after years of constant use.

If you have a bearing spare though, use it! 😁

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