Bearings, Linear Bearings, rails, lead screws etc

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Re: Bearings, Linear Bearings, rails, lead screws etc

Postby Tweakie » Mon May 24, 2010 12:16 pm

Nice one LS. :D
I think we would be disappointed with the accuracy if we made these V-Groove ourselves from skate bearings. Possibly the cost of the genuine items is related to the dual row of angular contact balls which significantly reduce the axial movement under load. Don't you just get what you pay for in life ?. :D

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Re: Bearings, Linear Bearings, rails, lead screws etc

Postby bdring » Mon May 24, 2010 12:52 pm

I am familiar with the construction of those bearings.

I was doubtful too of the dual bearing idea until I tried it. There is some axial play, but way less than I thought there would be. As long as the axial play does not increase the rolling resistance significantly and does not change over time, it may work. My initial concern is wear on the track, not in the bearing. The track is available with hardened rolling surfaces, but that might not be needed. The track may only require a break in period. Who knows. I may make test section an run a couple hundred hours on it.

I would never use this on a heavy CNC router, but on something where the load is a couple of pounds at most

An old boss would say when this when someone tried to shoot down a new idea.

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Re: Bearings, Linear Bearings, rails, lead screws etc

Postby Tweakie » Mon May 24, 2010 1:20 pm

I agree 100% Bart. It would be good to try a prototype and see the results of your dual bearing idea. (it is my impression that LS was referring to a single skate bearing).
If we did not think outside the box there would be no innovation at all.

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Re: Bearings, Linear Bearings, rails, lead screws etc

Postby bdring » Mon May 24, 2010 1:37 pm

If the LS1 idea uses dual bearings it is probably even better than my idea, but a lot more initial work. I'll bet his USL wheels have two bearings inside that rubber wheel.

With my idea the side load is not the real problem, but axial play (the inner race twisting with respect to the out race). Once you put two bearings into a molded or machined carrier this is almost eliminated. You still have the side load issue, the the twist is not a problem anymore.
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Re: Bearings, Linear Bearings, rails, lead screws etc

Postby Ben » Wed May 26, 2010 12:51 am

lasersafe1s idea could also be printed on a 3D printer such as a Makerbot, RepRap Darwin, or RepRap Mendel. If printed on an open source 3D printer they would be extremely cheap (at least to produce :D ) and could be made out of ABS, PLA, HDPE, or similar thermoplastics.

I would volunteer to print a few on my RepRap Mendel, but at this time its print quality is not up to par with bearing standards :( . There are people who have 3D printers that would be capable of making such prints Example: http://hydraraptor.blogspot.com/2010/04/abs-on-pet-tape.html
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Big VXB Price Drop

Postby bdring » Wed Jun 09, 2010 12:25 pm

The bearings at VBX just dropped by over 20% to $7.77 each!
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