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Jon_Doe
10-05-2015, 08:08 AM
Hi everyone.

I am looking for advice on how to make bearing housing/supports/mounts.
By that i mean some basic "pipe" with the right ID for the bearing and with the shoulder/lip so the bearing sits where it should.
This piece will be welded to various members.

I can have a machinist do this to microns but that is not the issue.
My issue is with metal protection (from rust).
On the outside there will be paint.
But on the inside, especially on the bearing's seat ?
I did not manage to get paint in consistent thickness and even if i could, it would strip in no time.

I've seen it done with paint on the outside and nothing on the inside but that was on aluminum.
I can only get mild steel over here, everything else is unobtanium.

Please help me figure out a way to solve this since water always wins and gets in where you want it the least.

darnthedog
10-05-2015, 10:44 AM
This is a case where photos would make a world of difference to show us what you are referring to.

If your referring to the spacer within hubs that keep the inner bearing race from being crushed. That can be made of almost anything including plastic pipe as it is not load bearing.
However before all this became available a good liberal coating of grease applied on a regular basis would reduce the amount of rust and water that gets into those tight places.

But it is a lot of work as you have to pull the bearings out to coat it well. If your only worried about the inner surface just grease the axle the bearings ride on. Should keep the rust away.

Hope that helps.

Jon_Doe
10-07-2015, 07:46 AM
Let's see now.

In the following site (http://www.motorcycleclassics.com/mc-how-to/bmw-5-swingarm-bearing-service.aspx), starting with the following image (http://www.motorcycleclassics.com/~/media/Images/MCC/Editorial/Blogs/MC%20How-To/BMW%205%20Swingarm%20Bearing%20Service/08-01-12-howto-11.jpg?la=en).
There is a swingarm who uses bearings in it's pivot.
The bearings are pressed in the swingarm.
The swingarm hole to receive the bearing (in this case it's outer race) is machined for a precise fit.
This is needed so the bearing does not come loose with use.

But the swingarm is made of aluminum, therefore paint has only decorative purposes since aluminum does not rust.

Now imagine i build a mild steel swingarm/hub/whatever.
The bearing receiving "hole" must be protected from moisture, otherwise rust settles in.
Grease alone won't cut it since, in my experience, water does get in no matter what.
And i can't regrease every other month since that would mean taking out the bearing ...

Paint is no good if press fitting (except if it's superpaint in a very thin coat - is there such paint ?)
I could galvanize the steel but after welding the zinc layer will be gone in places.
Also, with any surface covering (paint, zinc coating) there is a layer thickness.
I need to be very precise about this but historically it has been proven very difficult.


So, how do i go about this ?

LongRider
10-07-2015, 08:29 AM
In my experience, since the bearings are press fit into the swing arm -- press fit tightly, that the only time you will have any problem with rusting in the area between the bearing and the swing arm is if you were to be operating under water for extended periods of time....

Seriously though, just paint the thing when assembled and it will be protected, the paint will cover the micron thick area where you fear water may enter.

Jon_Doe
10-07-2015, 08:45 AM
Ok, makes sense (mostly).

Just curious, are there any commercial brands using steel for this scenario ?
If yes, how do they do it ?

darnthedog
10-07-2015, 12:04 PM
The scrap bike I get have either lead bushings or plastic bushings and not bearings. They are split in two and are held together with Stainless hex screw. Swing arms typically do not have bearing here. However one member could not find a swing arm to use so he built his own. You can read about it here: http://forum.atomiczombie.com/showthread.php/7119-First-Bike-Build
The poster pasted away but his contribution lives on. So feel free to read it but he will not be able to respond to questions.

Hope that helps.

ken will
10-07-2015, 04:43 PM
I used a Huffy Head-tube for the swing-arm pivot on this sidecar.

https://pqzmfg-dm2305.files.1drv.com/y3p-EeBkVjyKB_TNXdXN58VmtaKLIcXVuWL-vYvPmIRjewxga3EgLQmV2bDSy7e1oI9BIsGwziLOVBXUTGKrIu-IN6dyRKd7JSAsgg5gYr0f1CbByP0Hw2T2ohZXsb_9V-ewbP-Gz13YrnewCD6vVC8GicP5yYzNiAfWqDk-zWUkQs/sidecarA.JPG?psid=1

https://pqzmfg-dm2305.files.1drv.com/y3p539T5DLhK1Mu-Qv51CmYmO7KV2CnvPlMKQbJsOh3470-FoT9YqYZ8YSVRcGkjaFvtXE6Y04ieuzBEOeIK8eD67NgNTHHEF xKHWUR6-nsFRHaLtYQJKmb-yUXbYCGNWEtT4Fa2DphUg_YbNbm1OC8LCjIRGznAjRkIe5zcfv dmgw/HuffyPivot.JPG?psid=1

https://pqzmfg-dm2305.files.1drv.com/y3p30eioHfu7lyV9V-Qh3rVoIs1AkYrwtfwQU8tcXI2CgCklHhkQ8itCdSwcGttBJMw-FURfJh6Kzbtr26iMkEi5j9Md-w8rgIiKqt6cJffGQHea7GIcXbmRIpoDtszuinLuKwd9sbusNmO 5Ay9F6Sy5dxYlOqDtMRxhN83Im85Wds/After.JPG?psid=1

Penola
10-07-2015, 10:55 PM
I would fit a grease nipple in the center.
then I could use a grease gun to regularly refill with fresh grease and i this way force out spend grease ensuring that impurities etc are forced out of the bearing.
just need to wipe old grease away at regular intervals.

most heavy duty earth moving machinery work like this in the most severe conditions without problems.

just an idea

Jon_Doe
10-08-2015, 03:38 AM
Thank you all for the info.

Whatever water penetration issue happens with bearings will also happen with bushings.
My current build (http://forum.atomiczombie.com/showthread.php/9627-Kiddy-mover-in-progress) uses shoulder nylon bushings (a friend machined them for me) stuck at the ends of some 3/4" and 2&1/2" pipe (this pipe forms the housing).
The bushings are still press fit into the housing just as with bearings so the issue is the same.
The scrap bikes i had used steel on steel bushings which turned into one part after water came in turning it into a powerful weld.
I scrapped those parts.

Motorcycle parts are just too darn expensive around here for any practical benefit (there are exceptions though).

A benefit for bushings is larger contact area but disadvantage is pivot shaft wear.
If this shaft is galvanized, i won't care.
But if the superficial Zn coating (15 microns) wears (and it will wear out pretty quickly, i've seen it) and there is little moisture present, that's it.
On the other hand, the shaft will never wear with bearings.
I've seen some BMW motorbikes using tapered roller bearings in the swingarm and never had a bearing change in the whole life.
They need preload but it's not hard to achieve and it's a one time only operation.
On the other hand, they also use aluminum and shaft seals (https://www.google.ro/search?q=shaft+ring&safe=off&tbm=isch&tbo=u&source=univ&sa=X&ved=0CCcQsARqFQoTCN2gkaepssgCFYHMGgod00gM1g&biw=1228&bih=951#safe=off&tbm=isch&q=rotary+shaft+seal).

So, if one wants to be absolutely covered, shaft seals are a necessity (with bearings or bushings).
Adding a grease zerk might help but having a proper design in the first place will help even more.

Take a look at how it's done in this BMW bike (http://www.motorcycleclassics.com/mc-how-to/bmw-5-swingarm-bearing-service.aspx).
One option would be to have the seal area have a slightly larger diameter and painted.
It should have a final diameter (after painting) slightly larger than the bearing so that the bearing slides thru this part and doesn't remove the paint. The seal is elastic and won't care if it's press fit into a hole 0.1 mm larger.
You might think i'm overengineering things but i'm actually not.
I need a bike for all conditions.
My experience is water wins hands down if you're not doing things right.
And in wintertime, we have a lot of salt on our roads which leads to salty muddy gunk everywhere on the bike.
You don't want to know what this does to sensitive parts (Like exposed metal).

So i'm not actually paranoid, i just want something that lasts, not just for a season.

PS
A rear car tapered roller bearing can be had for about $5 which is maybe less than a plastic bushing (specially machined, not off the shelf).
That bearing will last forever in a trike pivot.

PS2
Shaft collars i have been unable to find and i imagine if i did would turn terribly expensive.
They would also be open to the elements as shown in the link posted by darnthedog (http://forum.atomiczombie.com/member.php/408-darnthedog).

DannyC
10-08-2015, 04:54 AM
Hi Jon_doe,

Is this for a Street-Fox rear suspended wheel (or similar)?
In most of the units I have seen disassembled it is true that the pivot bolts are generally rusted up and after a while the nylon inserts start to wear and their inner "holes" go oval.

But, this only happens after some little while and it is always the ingress of water & dirt that does the damage (as you say).
Most rear suspension tubes have sufficient gap for the installation of a screw-in grease-nipple and the packing (and topping-up) with a good high-melting-point grease ought to be good enough to protect it (for a good amount of time, at least).
Given that a complete bearing set (nylon press-fit bushes and replacement pivot pin) is only about 5 (<$8) surely this becomes a periodic maintenance job for replacement every few years?
It's a relatively quick operation to replace the entire set, and you are then good to go for another few years.
http://www.ebay.co.uk/itm/FULL-SUSPENSION-BIKE-PIVOT-BOLT-BUSH-SET-ALLOY-FS1-75mm-30-32mm-RALEIGH-AMEYA-/391285082293?hash=item5b1a6888b5
The suspension pivot "tube" seems to be fairly common in terms of ID/OD so perhaps this is an economic approach if not a perfect engineering solution?

Jon_Doe
10-08-2015, 05:54 AM
Hy Danny,

My trike, as seen here (http://forum.atomiczombie.com/showthread.php/9627-Kiddy-mover-in-progress) (i'll update to more recent photos when i get some time) uses a piece of 2&1/2" pipe with plastic bushings specially machined by a friend. I did this since everything else failed to materialize.
I've searched all shops (even auto and moto) without success (there were parts that could be made to fit the purpose but much too expensive).
The trike is finished. Even if i'm pretty unhappy about how it turned out for various reasons.
There won't probably be any "upgrades" since i lack time for them.
Probably only things done "for else it would break".
It is just a matter of time until it breakes to pieces because of rust and wear (i am exagerating but this is how i feel).

My questions were more on the line of how it should have been done.

regarding the ebay items, nice. Nice for you.
I don't have that luxury. Transport is not cheap.
And i've already had the unpleasant surprise to order off the shelf parts thinking they'll do the job only to find they had abysmal quality (manufacturing and concept).
So that is where i am right now.
Thinking how i could have done it great except mediocre.