Hi all...
the more I learn, the more I find out I don't know.
I've had 2 instances this week (and it's only Wednesday) where I've seen things I thought were a good idea, then had it explained to me, they aren't, it's made me realise that the people that designed repRap are certainly better engineers than me (I'm not an engineer), and sometimes they are better engineers than those designing upgrades. I'm very happy with my Huxley, but I'm a tinkerer, and I was going to print some upgrades, I've seen lots published.
1. Z Wobble, and how it affects your layers.
I noticed my threaded rods wobble around on Huxley, I'd noticed a printable part on thingiverse that you can print to constrain your rods.
Someone had designed it to stop them moving at the bottom.
Here is a short article, with engineering principles explained, on why they wobble, and why that's fine. Infact constraining them at the bottom will not help quality, and it may make things worse, as it will put a load on your Z smooth rods.
Z Wobble
2. Changing bushes to linear bearings.
I was searching for an adjustable Z stop. I came across a printable X end that had a z stop adjuster included. Nice it is.
Except, it's changed the bushes to bearings, which would make things worse on your X end. Because of the direction of travel (with gravity along the shaft), there is no preloading of the linear bearing, and linear bearings need preload. so this would be a downgrade not an upgrade.
I've not printed any upgrades yet, but I'm certainly going to be careful if I do.