<![CDATA[SoliForum - 3D Printing Community — Metal version of Thingiverse "Threadless Ballscrew"]]> 2014-06-10T04:56:13Z PunBB https://www.soliforum.com/topic/3691/metal-version-of-thingiverse-threadless-ballscrew/ <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> Are these being made still. I would be interested in one

]]> https://www.soliforum.com/user/5652/ 2014-06-10T04:56:13Z https://www.soliforum.com/post/58306/#p58306 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> How accurate and repeatable is this leadscrew rider?

Got a thread in RepRap Forum

http://forums.reprap.org/read.php?14,328230

with all kinds of tests?

I am looking for an accurate / repeatable  design / items.

Tnx

]]> https://www.soliforum.com/user/264/ 2014-04-30T23:28:03Z https://www.soliforum.com/post/55418/#p55418 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]>

Is it gravity in respect to the angle of the bearings?  Supposedly putting two bearing assemblies back to back gives you the same steps/mm in both directions.  Or is the extra support of the second assembly preventing the slippage?

This I have tried. Although you effectively double the surface area on the shaft, you increase torsional resistance on the rod. The stepper needs to be much more powerful/driven slow to account for this and the distance traveled is still asymmetrical, although to a lesser extent.

]]> https://www.soliforum.com/user/3270/ 2014-02-01T04:09:36Z https://www.soliforum.com/post/48361/#p48361 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> The angle of the bearing dictates how much surface area is on the harden shaft so gravity plays it's part on the resistance from the bearings to the harden shaft.

I would imagine that it would increase resistance so it would help somewhat as to how much I have no clue since I've never
tried it.

]]> https://www.soliforum.com/user/2779/ 2013-12-14T08:37:22Z https://www.soliforum.com/post/44316/#p44316 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> Is it gravity in respect to the angle of the bearings?  Supposedly putting two bearing assemblies back to back gives you the same steps/mm in both directions.  Or is the extra support of the second assembly preventing the slippage?

]]> https://www.soliforum.com/user/14/ 2013-12-14T07:34:40Z https://www.soliforum.com/post/44315/#p44315 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> adrian wrote:
ITman496 wrote:

Oh, I didn't realize it micro-slipped.  Is it consistent?  Seems like it would cause accuracy problems..

its a constant in the respective directions, so is fine in that regard as it is factored in. But the constants are just different due to the different forces at play.

Adrian is 100% correct as usual smile
Threads allow the weight to be rested on where gravity is minute.

A threadless screw doesn't have that semi benefit however it does have the benefit of not having a small amount of backlash due to the fact that there are no threads and no gaps between threads.

]]> https://www.soliforum.com/user/2779/ 2013-12-14T03:36:00Z https://www.soliforum.com/post/44301/#p44301 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> ITman496 wrote:

Oh, I didn't realize it micro-slipped.  Is it consistent?  Seems like it would cause accuracy problems..

its a constant in the respective directions, so is fine in that regard as it is factored in. But the constants are just different due to the different forces at play.

]]> https://www.soliforum.com/user/663/ 2013-12-14T03:30:57Z https://www.soliforum.com/post/44300/#p44300 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> Oh, I didn't realize it micro-slipped.  Is it consistent?  Seems like it would cause accuracy problems..

]]> https://www.soliforum.com/user/2694/ 2013-12-14T03:17:56Z https://www.soliforum.com/post/44297/#p44297 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> they don't exhibit the same behavior in a horizontal plane, where they are more traditionally used within linear motion.... hence me dumbing it down to "gravity". pushing up, as the bearings roll against the face of the rod, they actually will microslip, causing less upward motion. Downwards they also microslip, but its in an advantageous direction.

I probably could have said 'friction coefficients' but that wasn't dumbing it down enough I thought (and I wasn't doing it for your benefit, more for making a simple explanation for greater and wider readership - so sorry if it seemed apparently condescending...)

But I am by no means an expert and could be full of it smile This is simply my understanding and extrapolated belief on the basis of their non-exhibition of the problem in a "parallel to earth" orientation...

]]> https://www.soliforum.com/user/663/ 2013-12-14T02:55:31Z https://www.soliforum.com/post/44294/#p44294 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> I mean, Adrian, I understand why it might slip more easily going up than down, but gravity doesn't really make sense as an explanation to me, though I could understand your giving that answer and that it could be true.

I thought these things climbed by being at slight angles, and riding up a "groove" [not really a groove] made by friction and the angle the bearings are at.

Does the angle the bearings make with the horizon change on the way down because it's not tilted the same way by the weight or something?

Does anyone have the trade journal paper that  describes these guys?  I guess I don't really understand how they work

]]> https://www.soliforum.com/user/192/ 2013-12-14T02:48:31Z https://www.soliforum.com/post/44293/#p44293 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> ITman496 wrote:

So does this one have that problem with uneven up/down movements?  I still don't understand why you need to rotate a different amount to go upwards..

In a simple one word answer - "Gravity".

Upwards you have to overcome the additional weight of pushing the platform 'up' which requires more energy than it does to push down where the weight of the platform assists movement which causes additional friction to overcome against the rod.

Consequently, an upward motion actually causes the bearings to 'climb' less than a downward motion enables them to 'descend' .

]]> https://www.soliforum.com/user/663/ 2013-12-14T01:10:29Z https://www.soliforum.com/post/44275/#p44275 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> So does this one have that problem with uneven up/down movements?  I still don't understand why you need to rotate a different amount to go upwards..

]]> https://www.soliforum.com/user/2694/ 2013-12-14T00:49:56Z https://www.soliforum.com/post/44270/#p44270 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> This weekend I'll have a big teaser pic up

]]> https://www.soliforum.com/user/2779/ 2013-12-13T20:58:29Z https://www.soliforum.com/post/44253/#p44253 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> Going to run the printed version next week when my coupler arrives.

Any more pics to tease us?

]]> https://www.soliforum.com/user/1682/ 2013-12-13T19:43:22Z https://www.soliforum.com/post/44241/#p44241 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> Sounds good. I'll keep an eye out.

]]> https://www.soliforum.com/user/1682/ 2013-11-27T15:40:03Z https://www.soliforum.com/post/42690/#p42690