<![CDATA[SoliForum - 3D Printing Community — Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/topic/3691/metal-version-of-thingiverse-threadless-ballscrew/ Tue, 10 Jun 2014 04:56:13 +0000 PunBB <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/58306/#p58306 Are these being made still. I would be interested in one

]]> Tue, 10 Jun 2014 04:56:13 +0000 https://www.soliforum.com/post/58306/#p58306 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/55418/#p55418 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

]]> Wed, 30 Apr 2014 23:28:03 +0000 https://www.soliforum.com/post/55418/#p55418 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/48361/#p48361

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.

]]> Sat, 01 Feb 2014 04:09:36 +0000 https://www.soliforum.com/post/48361/#p48361 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/44316/#p44316 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.

]]> Sat, 14 Dec 2013 08:37:22 +0000 https://www.soliforum.com/post/44316/#p44316 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/44315/#p44315 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?

]]> Sat, 14 Dec 2013 07:34:40 +0000 https://www.soliforum.com/post/44315/#p44315 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/44301/#p44301 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.

]]> Sat, 14 Dec 2013 03:36:00 +0000 https://www.soliforum.com/post/44301/#p44301 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/44300/#p44300 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.

]]> Sat, 14 Dec 2013 03:30:57 +0000 https://www.soliforum.com/post/44300/#p44300 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/44297/#p44297 Oh, I didn't realize it micro-slipped.  Is it consistent?  Seems like it would cause accuracy problems..

]]> Sat, 14 Dec 2013 03:17:56 +0000 https://www.soliforum.com/post/44297/#p44297 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/44294/#p44294 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...

]]> Sat, 14 Dec 2013 02:55:31 +0000 https://www.soliforum.com/post/44294/#p44294 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/44293/#p44293 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

]]> Sat, 14 Dec 2013 02:48:31 +0000 https://www.soliforum.com/post/44293/#p44293 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/44275/#p44275 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' .

]]> Sat, 14 Dec 2013 01:10:29 +0000 https://www.soliforum.com/post/44275/#p44275 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/44270/#p44270 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..

]]> Sat, 14 Dec 2013 00:49:56 +0000 https://www.soliforum.com/post/44270/#p44270 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/44253/#p44253 This weekend I'll have a big teaser pic up

]]> Fri, 13 Dec 2013 20:58:29 +0000 https://www.soliforum.com/post/44253/#p44253 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/44241/#p44241 Going to run the printed version next week when my coupler arrives.

Any more pics to tease us?

]]> Fri, 13 Dec 2013 19:43:22 +0000 https://www.soliforum.com/post/44241/#p44241 <![CDATA[Re: Metal version of Thingiverse "Threadless Ballscrew"]]> https://www.soliforum.com/post/42690/#p42690 Sounds good. I'll keep an eye out.

]]> Wed, 27 Nov 2013 15:40:03 +0000 https://www.soliforum.com/post/42690/#p42690