Gluing bearings into diff housing

[Mopsik_Klopsik]

Is it a good idea to glue the bearings into the diff housing? Would it be problematic to dissasemble them? I want to use loctite 270. I have tried a couple of different bearings but only the original ones have tight enough fit. For now the original bearings are fine but I would like not to be dependent on them and be able to use different ones ( available locally ) when these breake.

 

[King blitz]

Is it a good idea to glue the bearings into the diff housing? Would it be problematic to dissasemble them? I want to use loctite 270. I have tried a couple of different bearings but only the original ones have tight enough fit. For now the original bearings are fine but I would like not to be dependent on them and be able to use different ones ( available locally ) when these breake.

View attachment 346212

I don't believe it's a good idea to glue your bearings into the diff housing

 

[Garcbomber]

Outside bearing race always green loctite bearing retainer into alloy, the last thing you want is a bearing to seize and destroy the capture diameter of bulkheads/hubs/etc.

Inner race is surrounded by carbon steel outputs/stubs, if you dig long enough through that you have bigger issues in hearing and attention.

Carbon 45 steel is much harder than even tempered 7075 alloy.

 

[gotnitro]

Bearings should have a tight press into their housing. Sometimes they snap right in but if you have any type of play, that's not the bearing if you've tried different ones, most likely that's the diff housings improper machining tolerances. Never glue in bearings..

 

[Jluther@becoinc]

Is it a good idea to glue the bearings into the diff housing? Would it be problematic to dissasemble them? I want to use loctite 270. I have tried a couple of different bearings but only the original ones have tight enough fit. For now the original bearings are fine but I would like not to be dependent on them and be able to use different ones ( available locally ) when these breake.

View attachment 346212

What brand of diff housing is that? Looks like M2C hinge pin blocks. They are the toughest set up I’ve found.
Looks like you’re putting one together the right way for sure.

 

[Mopsik_Klopsik]

Outside bearing race always green loctite bearing retainer into alloy, the last thing you want is a bearing to seize and destroy the capture diameter of bulkheads/hubs/etc.

Inner race is surrounded by carbon steel outputs/stubs, if you dig long enough through that you have bigger issues in hearing and attention.

Carbon 45 steel is much harder than even tempered 7075 alloy.

What kind of loctite do you use and how much of it? They told me in the shop that 638 and 270 is often used interchangeably. Loctite 270 looks green-ish.

What brand of diff housing is that? Looks like M2C hinge pin blocks. They are the toughest set up I’ve found.
Looks like you’re putting one together the right way for sure.

scorched parts

 

[Hector_Fisher]

What potential benefit do you expect to get by gluing your bearing in place?

Bearings are a disposable, consumable item. Designed with a lifespan in mind and to be replaced at some given frequency, and you can tell because of how "easy" they are to replace on RC cars. Don't defeat that built-in, convenient, cost-saving design by gluing the bearings in place.

 

[Jluther@becoinc]

What kind of loctite do you use and how much of it? They told me in the shop that 638 and 270 is often used interchangeably. Loctite 270 looks green-ish.

scorched parts

All of that scorched?

 

[Mopsik_Klopsik]

What potential benefit do you expect to get by gluing your bearing in place?

Bearings are a disposable, consumable item. Designed with a lifespan in mind and to be replaced at some given frequency, and you can tell because of how "easy" they are to replace on RC cars. Don't defeat that built-in, convenient, cost-saving design by gluing the bearings in place.

Bearings other than stock ( included with diff housing ) don't fit tight inside housing. On high rpms the outside race of bearing will start to spin and gonna destroy the housing. Gluing bearings in will prevent that from happening.

All of that scorched?

diff housing only

 

[jkflow]

That is a bad tolerance on the machining and as much as I'd hate to say it you would have to secure them somehow. I'd go with blue loctite and see how it works.
You will have to replace bearings once/twice per season if you are doing it right.
You could use stronger versions but you would need heat to get them out.

Raz had a video on this as to why he isn't able to get one made yet.

Hence I don't like metal bulkheads, the tolerance on everything is not as tight as needed for a metal part, but that is just me. Plastic is crap as well but more forgiving.

 

[Garcbomber]

What kind of loctite do you use and how much of it? They told me in the shop that 638 and 270 is often used interchangeably. Loctite 270 looks green-ish.

scorched parts

Don't use a lot, just a finger rub around the race mate. Otherwise you'll have to heat them up to remove. 620 will also suffice up to 450F

 

[Mopsik_Klopsik]

That is a bad tolerance on the machining and as much as I'd hate to say it you would have to secure them somehow. I'd go with blue loctite and see how it works.
You will have to replace bearings once/twice per season if you are doing it right.
You could use stronger versions but you would need heat to get them out.

Raz had a video on this as to why he isn't able to get one made yet.

Hence I don't like metal bulkheads, the tolerance on everything is not as tight as needed for a metal part, but that is just me. Plastic is crap as well but more forgiving.

Yes, it look like the original Scorched Parts bearings have different tolerance than many others I have tried, hence they have good fit. I have two options:
Use only the original Scorched Parts bearings or.... Be able to use other bearings but have to glue them in.

 

[Hector_Fisher]

Bearings other than stock ( included with diff housing ) don't fit tight inside housing. On high rpms the outside race of bearing will start to spin and gonna destroy the housing. Gluing bearings in will prevent that from happening.

diff housing only

I'll take a slightly different approach than most here: it depends.

First of all, if an RC bearing is functioning properly and in good health, the outside shouldn't be spinning. If there is even minimal resistance on the outside race, the inner race should spin freely. For short shafts like stub axles or diff pinions, these will experiencing bending motions on one end -- like the wheel touching the ground and pushing up on the stub axles, or the diff pinion being pushed away from the sun gear. These kinds of forces will cause the bearing to "seat" or bias into one place in the housing. Even if there is some slop, the bearing will be forced into one side of it's seating surface, thereby not really moving much if at all. So in most cases, even with slightly loose tolerances, the bearing would likely still function properly. I would only consider some slop to be an issue if it's really an extreme case. Take this an as example of what i considered unacceptable slop: https://www.arrmaforum.com/threads/slop-in-aluminum-3s-diff-yoke.59454/

Overall, if you have what you feel to be unacceptable slop, gluing in place isn't the right answer. Getting a properly machine part is the correct answer, as difficult of a response as that may be.

 

[Garcbomber]

I'll take a slightly different approach than most here: it depends.

First of all, if an RC bearing is functioning properly and in good health, the outside shouldn't be spinning. If there is even minimal resistance on the outside race, the inner race should spin freely. For short shafts like stub axles or diff pinions, these will experiencing bending motions on one end -- like the wheel touching the ground and pushing up on the stub axles, or the diff pinion being pushed away from the sun gear. These kinds of forces will cause the bearing to "seat" or bias into one place in the housing. Even if there is some slop, the bearing will be forced into one side of it's seating surface, thereby not really moving much if at all. So in most cases, even with slightly loose tolerances, the bearing would likely still function properly. I would only consider some slop to be an issue if it's really an extreme case. Take this an as example of what i considered unacceptable slop: https://www.arrmaforum.com/threads/slop-in-aluminum-3s-diff-yoke.59454/

Overall, if you have what you feel to be unacceptable slop, gluing in place isn't the right answer. Getting a properly machine part is the correct answer, as difficult of a response as that may be.

You have stack up tolerances in both bearings being concentric when they're milled between both components, my tri-bearing hubs absolutely need slip plus OD fitment otherwise bearing manufacturer tolerances aren't good enough to prevent binding with robust ball/race assemblies.

Different strokes for different folks , my rigs spin bearings 4-5k rpms with heavy off-road tires that aren't perfectly balanced due to snow/mud/elements. I'm sure it's fine for on road light wheel one-trick-pony applications, until the one time it isn't and you're out a bulkhead or hub...

 

[Jluther@becoinc]

What kind of loctite do you use and how much of it? They told me in the shop that 638 and 270 is often used interchangeably. Loctite 270 looks green-ish.

scorched parts

I haven’t used scorched diff housings . I do use Hot Racing and Vitavon and have never had any fitment issue at all.
They fit tight and cut stripped gears out of my maintenance. Bearings do go out but not nearly as often cause they don’t move. I’ve changed all my 6s vehicles to aluminum 8 or 9 of them. A few thousand dollars and now they come stock. LOL

 

[Hector_Fisher]

You have stack up tolerances in both bearings being concentric when they're milled between both components, my tri-bearing hubs absolutely need slip plus OD fitment otherwise bearing manufacturer tolerances aren't good enough to prevent binding with robust ball/race assemblies.

Different strokes for different folks , my rigs spin bearings 4-5k rpms with heavy off-road tires that aren't perfectly balanced due to snow/mud/elements. I'm sure it's fine for on road light wheel one-trick-pony applications, until the one time it isn't and you're out a bulkhead or hub...

Agreed, I just don't think the level of tolerances we're speaking about mean as much on an assembly that will see a small fraction of the use time as say something from the auto industry. I have to believe that bearings at this scale are made to be cheap and easily replaceable. If the tolerances in the RC industry were such that people were throwing bearing every other day -- a financial burden -- then I think we'd naturally see them tighten up. But because it's not really a matter of passenger safety and the liability of a failed part (bearing) is low, tolerances are not held to that same level as say the auto industry.

There's a gradient between maintaining 1/10,000th inch tolerances and having it working 100% pristinely, and having 0.1 inch tolerances and have it work. Arguably the tighter tolerances will last longer, but if they both work are the tighter tolerances worth it? I think the long term cost is the answer.

 

[SrC]

Is it a good idea to glue the bearings into the diff housing? Would it be problematic to dissasemble them? I want to use loctite 270. I have tried a couple of different bearings but only the original ones have tight enough fit. For now the original bearings are fine but I would like not to be dependent on them and be able to use different ones ( available locally ) when these breake.

View attachment 346212

Do you have any specific reason why you would want to do that is the question?? These are technically press fit.
I feel the opposite and I smear some light grease on the outer of the BB's before inserting them into Metal carriers. I don't need them to be permanently Fixed. These Input outer BB;s are know to fail often, and are replaced often for this reason.
>>>If using TL 270 is due to a poor BB fitment issue, and if so , you have a bigger problem there to deal with and resolve.
Green 270 is only used on the threads of fasteners and torqued to each other.

 

[Eno]

Getting a properly machine part is the correct answer

Yes!