legoman666

Ball bearings!

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For those of you who use brass tubing to create brick built trucks for your rolling stock, I have something better that will blow your mind.

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Standard Lego train axle.

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It's a video, click the image to take yourself to flickr to view.

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Another video, courtesy Cale.

The bearings are size 2mm x 5mm x 2.5mm. The seller many of us bought from is here: http://www.ebay.com/itm/401163945360 although simply searching 'MR52ZZ' will yield many results. From the 2 batches I've bought from 2 different sellers, I did notice a difference in performance with the crown going to the seller linked above. The other batch still performed better than both Lego's standard train axles and brass tubes.

Technic axle holes are 4.8mm, so shoving a 5mm bearing into it requires a fair bit of effort, but it'll go. I use a hot air gun to soften the plastic slightly for an easier fit.

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That's a really good price on those bearings. I experimented with it some years ago, but at $5/ bearing, I didn't do anything more than 2x axles, though my results were similar. If you drill out the Technic brick with a #9 drill it should press in nicely. Also, the trade no. could also be a 52-2Z instead of ZZ (both are used and acceptable), so that will give you some additional search results. If you have a lot of heavy rolling stock, this might be a worthwhile project for you.

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I had a quick look on McMaster-Carr, and found some ball bearings with a 4.8mm (3/16 in) OD: http://www.mcmaster....arings/=148m2ci

They'll probably be more expensive than the ones you can get off ebay, but my guess is the quality will be a lot more consistent between each bearing as well as between each order. And, you can get them in all sorts of types: shielded, not shielded, greased, plastic, hex-shaft ID, and so on...

According to the blurb at the top of the page, I would suggest going for double-shielded bearings if possible, since they are more resistant to various contaminants - and I imagine right around the tracks, especially at shows, is going to be particularly bad in terms of dust and grit. Apparently, ZZ stands for a double-shielded bearing, with a ZS indicating a removable shield (so a ZZS would be a double-shielded bearing with one of the shields removable).

Edited by Phoxtane

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Except the 3/16" OD ones don't come in a Ø5/64" shaft size; your options are .055 (1.4mm) or 3/32" (2.4mm). The double-shielded ones are also about $10 apiece.

I think you'll be fine with the ones you have. These aren't what I'd consider dirty environments, so I don't think you'll need shielded ones. And the ones you have are cheap enough that if one does get gritty beyond repair, you can pop it out and just replace it.

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Ah, if I had known the inner diameter I wouldn't have bothered - looks like the ones McMaster-Carr carries in the 5/64" ID are limited to 1/4" OD. The nice thing about the ebay bearings is that they are ZZ (double shielded) bearings, so in theory they'll be plenty resistant to any ABS dust or grit that will accumulate.

Actually, another issue that may present itself is whether or not these bearings are lubricated. They may have more rolling resistance if they're lubricated, but they will last much longer because there isn't nearly as much metal-on-metal grinding action. If I had to guess, maybe the reason why some bearings roll more freely than others is because they weren't properly lubricated (or weren't at all to begin with). I'd be curious to see someone tear apart one to see whether or not these are lubed.

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If they're like the McMaster ones, they are lubricated with oil. However, if they use a thin enough one, it shouldn't have much effect on rolling resistance, especially compared to the steel-on-ABS or ABS-on-ABS we have as standard.

For reference, here's the McMaster equivalent:

http://www.mcmaster.com/#7804k119/

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That's a really good price on those bearings. I experimented with it some years ago, but at $5/ bearing, I didn't do anything more than 2x axles, though my results were similar. If you drill out the Technic brick with a #9 drill it should press in nicely. Also, the trade no. could also be a 52-2Z instead of ZZ (both are used and acceptable), so that will give you some additional search results. If you have a lot of heavy rolling stock, this might be a worthwhile project for you.

These are $10 per 50. So it costs $1.60 to kit out 4 axles worth. No brass tubes to cut.

They work awesome. And they are not oiled, I had to oil them myself. I used 3-1, but honestly something lighter would be better.

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I know my classmates use sewing machine oil for the bearings on their longboards. Don't know if it's any lighter or not.

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These are $10 per 50. So it costs $1.60 to kit out 4 axles worth. No brass tubes to cut.

They work awesome. And they are not oiled, I had to oil them myself. I used 3-1, but honestly something lighter would be better.

Yeah, that was what I meant. When I did it before, I paid $5 apiece, so 50 for $10 is awesome. I'll probably pick up a set. Or 10.

Sewing machine oil or air tool oil would probably work great.

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that is great! I should try these on the Horizon Express (it is so heavy it eats AAA batteries for breakfast!). 

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I've just received some. As well trying them in standard technic holes, I'm gonna see if I can't get the standard wheelset to run smoother with the inclusion of bearings between the axle and the housing (because at 7 wide, there's not much space for brick built wheelside details.

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1 hour ago, Redimus said:

I've just received some. As well trying them in standard technic holes, I'm gonna see if I can't get the standard wheelset to run smoother with the inclusion of bearings between the axle and the housing (because at 7 wide, there's not much space for brick built wheelside details.

I'm interested in how this works out, since I don't do too many brick built wheelsets myself.

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Wow, This is awesome. I'm taking note of this. By the looks of it those Trains run very smooth with the addition of the  tiny ball bearings. Tho I wonder if the tiny ball bearing could potentially survive the high RPM from a fast RC motor.

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3 hours ago, Boxerlego said:

Wow, This is awesome. I'm taking note of this. By the looks of it those Trains run very smooth with the addition of the  tiny ball bearings. Tho I wonder if the tiny ball bearing could potentially survive the high RPM from a fast RC motor.

Looking at ball bearings of similar OD at McMaster Carr, even the ones with the lowest maximum RPM top out at 80k RPM - even if you derate the Ebay bearings by 50%, you could still push them to 40k RPM... That's with lubrication, of course!

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1 minute ago, Phoxtane said:

Looking at ball bearings of similar OD at McMaster Carr, even the ones with the lowest maximum RPM top out at 80k RPM - even if you derate the Ebay bearings by 50%, you could still push them to 40k RPM... That's with lubrication, of course!

Interesting, That sound great. Says alot for the tiny bearing. I checked out the those bearings on McMaster Carr, thoes are some good bearings they are like 7-15$ a piece. You are right about the Ebay bearings chances are they are probably just a lower grade but its still equally as strong bearings and probably capable of the 10lb max load weight like the others. Its certainly much easier connecting this up to a motor then trying to directly connect the Lego shaft directly to the RC motor. But going back on topic Here it would be powering a train, Now that would awesome to see a motor powering one of the trains with the ball bearing modification.

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If we could find bevel gears that are press fit on to 2mm shafts, then we could use these bearings in a transmission. I gave it a half hearted look the other day. Maybe one of you guys can find them :)

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5 hours ago, legoman666 said:

If we could find bevel gears that are press fit on to 2mm shafts, then we could use these bearings in a transmission. I gave it a half hearted look the other day. Maybe one of you guys can find them :)

2mm is pretty small.  I'm sure they could be made, but off the shelf, best I could find was 3mm:

http://sdp-si.com/products/miniature-gears-metric.htm#miter-gears-and-bevel-gears

You could try contacting them, see if they can run those with just a 2mm bore, but I think it unlikely, given how bevel teeth are cut.  You'd probably have to open it up to 4 or 5mm and press a bushing into it. 

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I purchased two sets of these ball bearings to mess around with. Will help quite a bit for some of the trains I am working on.

 

Thanks, Jeffinslaw

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On 9/19/2016 at 3:44 PM, legoman666 said:

They work awesome. And they are not oiled, I had to oil them myself. I used 3-1, but honestly something lighter would be better.

How did you oil the bearings if they're sealed? I'm considering some for my builds, but I'm waiting patiently for Redimus's results before I try and kit out my trains with them.

On 9/26/2016 at 3:58 PM, Redimus said:

 ...As well trying them in standard technic holes, I'm gonna see if I can't get the standard wheelset to run smoother with the inclusion of bearings between the axle and the housing (because at 7 wide, there's not much space for brick built wheelside details.

If this works without any modifications to the wheelsets, I'll definitely get my hands on these. If anything, it would mean I can pull longer trains for a longer amount of time on the same batteries (or, my batteries would last twice as long!).

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11 hours ago, Phoxtane said:

How did you oil the bearings if they're sealed? I'm considering some for my builds, but I'm waiting patiently for Redimus's results before I try and kit out my trains with them.

Oil wicks in through the gaps. 

 

Adding bearings to standard wheel sets is not going to decrease friction if youre still using the OG axle holder. If the standard holder has friction A, and a bearing friction B, in no universe will friction A + friction B be less than friction A.

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