Should be a fairly simple question to answer: How do the half bearings placed in the screw-holder work? Do they rotate with the screw within the screw-holder? Or does the drive screw rotate within the bearings? That is, do the bearings themselves move? [I'm asking because I'm designing a bootstrap extruder and it might be better if I use rectangular prisms of brass/etc with holes drilled in them, and then cut in half, to use as the half bearings; the square part would contact the screw holder, and the half cylinder hole would be where the screw goes. If the bearing is supposed to move within the screw holder, however, this wouldn't work, as the squareness would stop it from rotating independent of the holder.] Thanks! https://reprap.org/forum/read.php?14,14643,14643#msg-14643 Sun, 14 Jun 2026 12:29:34 -0400 Phorum 5.2.23 https://reprap.org/forum/read.php?14,14643,16283#msg-16283 https://reprap.org/forum/read.php?14,14643,16283#msg-16283 -------------------------------------------------------
> Sorry, maybe this is going to be a dumb question,
> but maybe not ;)
>
> ptfe is known to have a very low friction,
>
> isn't it possible to machine the halfbearing from
> the same piece of rod we use for the extruder
> insulation?

Well I tried something like this. I drilled a hole and then cut the shape I needed with a sharp knive. Works very well we already printed a screw holder part with the new ptfe bearings :)

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greetings
wizard23
[reprap.soup.io]]]> wizard23 Mechanics Fri, 29 Aug 2008 04:45:54 -0400 https://reprap.org/forum/read.php?14,14643,14910#msg-14910 https://reprap.org/forum/read.php?14,14643,14910#msg-14910
Demented]]> Demented Chihuahua Mechanics Fri, 25 Jul 2008 18:33:45 -0400 https://reprap.org/forum/read.php?14,14643,14660#msg-14660 https://reprap.org/forum/read.php?14,14643,14660#msg-14660 Forrest Higgs Mechanics Sun, 20 Jul 2008 12:00:25 -0400 https://reprap.org/forum/read.php?14,14643,14658#msg-14658 https://reprap.org/forum/read.php?14,14643,14658#msg-14658
ptfe is known to have a very low friction,

isn't it possible to machine the halfbearing from the same piece of rod we use for the extruder insulation?

'sid]]> sid Mechanics Sun, 20 Jul 2008 10:58:04 -0400 https://reprap.org/forum/read.php?14,14643,14653#msg-14653 https://reprap.org/forum/read.php?14,14643,14653#msg-14653 greenarrow Mechanics Sun, 20 Jul 2008 06:13:06 -0400 https://reprap.org/forum/read.php?14,14643,14647#msg-14647 https://reprap.org/forum/read.php?14,14643,14647#msg-14647 -------------------------------------------------------
> Joshua Merchant Wrote:
> --------------------------------------------------
> -----
> > it might be better if I use rectangular prisms
> of brass/etc with holes drilled in > them, and
> then cut in half, to use as the half bearings
>
> That's what I did. It works fine for me.


Wonderful! I love it when my options are expanded. Makes things so much easier.
Thanks!

Kyle Corbitt Wrote:
-------------------------------------------------------
> Bearings don't move - I think they're just round
> because you can get brass bar like that.

Ah. Well, I'm hoping that the option for using a squared bearing will increase the number of materials that I can use, which decreases cost and complexity (theoretically).

Edit, in response to Kyle's edit:
Heh, I was replying to his post when you posted. :D]]> Joshua Merchant Mechanics Sun, 20 Jul 2008 01:55:43 -0400 https://reprap.org/forum/read.php?14,14643,14646#msg-14646 https://reprap.org/forum/read.php?14,14643,14646#msg-14646
EDIT: had this thread open a while before I responded, whoops. Forrest got there first.]]> Kyle Corbitt Mechanics Sun, 20 Jul 2008 01:55:40 -0400 https://reprap.org/forum/read.php?14,14643,14644#msg-14644 https://reprap.org/forum/read.php?14,14643,14644#msg-14644 -------------------------------------------------------
> it might be better if I use rectangular prisms of brass/etc with holes drilled in > them, and then cut in half, to use as the half bearings

That's what I did. It works fine for me.]]> Forrest Higgs Mechanics Sun, 20 Jul 2008 01:46:01 -0400 https://reprap.org/forum/read.php?14,14643,14643#msg-14643 https://reprap.org/forum/read.php?14,14643,14643#msg-14643 How do the half bearings placed in the screw-holder work? Do they rotate with the screw within the screw-holder? Or does the drive screw rotate within the bearings? That is, do the bearings themselves move?

[I'm asking because I'm designing a bootstrap extruder and it might be better if I use rectangular prisms of brass/etc with holes drilled in them, and then cut in half, to use as the half bearings; the square part would contact the screw holder, and the half cylinder hole would be where the screw goes. If the bearing is supposed to move within the screw holder, however, this wouldn't work, as the squareness would stop it from rotating independent of the holder.]

Thanks!]]> Joshua Merchant Mechanics Sun, 20 Jul 2008 01:17:28 -0400