Where to get tiny inexpensive bearings?

[Robo_Pi]

I wasn't sure where to post this. I was going to post in "Can you help me find something?" but that seemed to be more about parts for machines. I was also thinking about posting this in "Stirling Engines" because that's one application I'll be using these bearings for. But I'll be using them in other projects as well.

What I'm looking for is a place to buy really cheap tiny bearings. They don't need to be good bearings. Sloppy bearings will do. Low cost is key.

I'm looking for bearings anywhere from about 3/8" to 3/4" O.D. And with a shaft hole diameter anywhere from 1/8" to 1/4". No measurments are critical and metric is just fine too. I'm just giving ball-park figures here to give an idea of about the size I'm looking for.

Thus far I found, and purchased, the following. These bearings are 10 cents each. Actually sold 10 for $1.00. I bought 100 of them for $10. But these are impossibly small. They have a shaft hole of 1mm and an O.D. of only 3mm.



I do have projects that I'll be using these on, so these are ok for those projects. But I would really like to find something a bit larger for similar cost. I mean, don't necessarily expect to pay 10 cents for a larger bearing. But I would like to get them for under a buck a piece if possible. The cheaper the better obviously.

They won't be carrying any load to speak off. Precision is not required. Just basically want some bearings to reduce friction. Sloppy bearings would actually be good.

So I just thought I'd toss this out here in case someone knows where to buy cheap bearings in bulk. I can easily find bearings I want for a few bucks a piece. But at the price things add up quite quickly. Also, as strange as it may seem, bearings of really high quality and precision can sometimes be sluggish to turn for something as weak as a Stirling engine, for example. A really good snug-fitting bearing can sometime require quite a bit of force just to get its oil moving. For a powerful motor that's not a problem. But for a Stirling engine that can be the difference between life and death.

So anyone know where I can buy super cheap bearings from about 3/8" to 3/4" in diameter?

~~~~

By the way, I can buy 1000 1/8" chrome precision bearing balls on eBay for $7.95 and free shipping. I'm currently thinking of going this route. Of course this would then require that I make the races to use them. But I'm thinking this might be the most cost effective way to go in the long haul.

Another option are these bicycle ring bearing cages. In bulk they come out to be about $0.50 a piece which is still a lot, but not too bad. The problem with these is that they are huge in diameter. Something I could work around, but not truly attractive. Plus I would still need to make the races for these too. May as well just go for the naked balls above at that point.

Anyway, I'm just toying with different ideas. I'm thinking about making a lot of Stirling Engines to sell and I'm trying to keep the cost as minimal as possible. I'm making other things that could use bearings too.

As a last resort I could do away with bearings entirely and just used the old-fashioned pointed end shafts as the bearings. That's on the table too.

I want to be able to sell these finished products at reasonable prices. So I don't want to end up putting $10 or $15 into the bearings alone. I'd have to tack that onto the finished price.

So I'm open to ideas for cheap bearings, or cheap bearing "work-a-rounds".

 

[Robo_Pi]

Just after I posted the OP I came up with an idea I never thought of before.

I mentioned the pointed-end shaft type of bearing surface. I was holding off on that as a last resort because the points on the bearing shafts will eventually wear down and become loose. But I just thought of an idea. I could buy the 1/8" Balls, and used those as bearing at each end of a pointed shaft. Just three balls in a pocket with the pointed shaft centered in between the three balls. This way the pointed shaft wouldn't be so quick to wear down.

I might go with that solution. The best of both worlds.

Unless someone comes up with a cheap supplier of small actual bearings.

It's often funny how you solve your own problems just by typing in a post.

I don't think I would have thought of that solution had I not written the OP.

 

[mcdanlj]

MR85 is what comes to my mind three. 5mm ID, 8mm OD, 2.5mm thick. Lots of examples on ebay of cheap ones about $0.10 /each in quantity.

 

[Robo_Pi]

MR85 is what comes to my mind three. 5mm ID, 8mm OD, 2.5mm thick. Lots of examples on ebay of cheap ones about $0.10 /each in quantity.

Thanks. I don't know how I missed those. Those tiny ones I got I also got from eBay. But I didn't see those MR85's. I'll pick some of those up too.

 

[hman]

Don't know if it's worth your time, but hard disk drives have some nice small-to-tiny ball bearings in them - both for the platters and for the read/write heads. Laptop size hard drives have even smaller bearings. I just took an old laptop drive apart (for the magnets), but didn't bother with the bearings. If the timing had worked out, I'd have been glad to stick 'em in an envelope and mail them to you. By the way, how many BBs are you looking for?

 

[Robo_Pi]

I was thinking of BBs too.

I do have a lot of junk computer drives laying around. I never thought of looking in them for bearings. Thanks for the tip.

I do a lot of different things and so I need bearings for different types of projects. Odd-ball bearings like I might find in old hard-drives will come in handy for my robot projects because I only build robots for myself. So there's no need to be consistent on any production level.

I was looking for some nice cheap bearings that I can buy large quantities of and design around so I can kind of "mass produce" some things without having to redesign each one for an odd-ball bearing.

I'm actually really happy with the idea I came up with in post #2. The idea of just tossing 3 ball bearings into a hole and using them as a bearing against a pointed shaft. I'm actually drawing this up in Sketchup. It's a really simple design and will be under 3 cents per bearing. Just drill or mill a 1/4" hole about 1/8" deep, toss three ball bearings in it so they just fit. Then lock them in with a thin plate, and a nice stainless steel rod with something like a 60 degree point on it will just fit in between the balls. That should work pretty well. Cheap, cheap, cheap. Yet not a bad design.

It's so cost effective it wins!

It still nice to have an assortment of other small bearings on hand too for special applications. But the three-ball bearing against a pointed shaft end is just too simple to pass up. No need for any serious races, just three balls in a hole and a pointed shaft. What could be simpler?

 

[extropic]

I recently bought one lot of 100 pieces of 608-2RS bearings from the link below. $20 delivered for 100 608s is what I call cheap. The problem is that they are very poor bearings (regardless of the sellers description). Most of the rubber seals were conical (seated in the outer race but protruding axially beyond the width of the inner races) and not in contact with the inner race at all. I could see light through the bearings, around the inner race. They seemed to turn smoothly enough, but without effective seals, that wouldn't last in my intended application. Because of the problem with the seals, I didn't do ant further evaluation so I have no dimensional data. I returned them and got a refund.

Cheap (and poor quality) 608-2RS Bearings

Good luck with your projects.

 

[cathead]

Take a look at Banggood. I just checked there and you can buy bearings in lots quite inexpensively.
They look to be in your size range and price.

 

[Robo_Pi]

@ extropic

Yeah, 100 pieces for $20 is cheap enough. I actually bought some of those. They work well for applications where there's no real load or high speed action for extended period of time. I imagine they are pretty much junk bearings as skateboard bearings. They'd probably wear out pretty quick in that application. I use them for drawer rollers. They aren't likely to ever wear out as drawer rollers. Especially for me since I'll most likely wear out first.

 

[Robo_Pi]

Take a look at Banggood. I just checked there and you can buy bearings in lots quite inexpensively.
They look to be in your size range and price.

Ooooo! Yeah, they have a really nice selection of specialized bearings. I'll definiitely be looking into what they have. They have thrust bearings, and pillow-block bearings and all sorts of special purpose bearings. And those prices do indeed look very reasonable. Thanks for the source.