Support for the top of the Z lead screw on an Ender 3 3D printer. This is to prevent accidentally bending the lead screw by rotating it by hand unsupported.
This is a new version of my earlier Z leadscrew support design https://www.thingiverse.com/thing:3358978 which was designed to be used in combination with the filament guide by Filboyt https://www.thingiverse.com/thing:2917932 and its derivatives.
After using these in combination for a while I found that the mount for the filament guide did not hold firmly as others have also found. I also found that my leadscrew support could move a bit more than I liked when using my leadscrew speed knob https://www.thingiverse.com/thing:3373265 which is great for moving the gantry quickly over a large distance.
I have therefore redesigned my z leadscrew support with a full length support to provide a more sung fit, and combined a filament guide mounting point. This stabilises the two greatly as each supports the other.
When attaching this to the printer lower the gantry to the bottom, and then remove the upper rail of the printer to enable the support bracket to slide into the T slots. Replace the top rail . Check that there is no pressure or friction on the lead screw, and that it can rotate freely. Then fit the knob (https://www.thingiverse.com/thing:3373265), and again check that the lead screw and knob rotate freely. Fit the filament guide into its mount: note this feature is deliberately a tight fit, and may need to be trimmed or lightly sanded depending on the quality/finish of your print.
UPDATE: Jan 20th 2020 added V2 which has a screw hole added for an M5 countersunk screw if desired. Will need an M5 thread tapped into the end of the extrusion. Note the major diameter of an M5 screw is larger than the filament holder dovetail, so may need some manipulation to get the screw in there (I have made the hole oversize at 5.2mm to provide some "wiggle room"). I have not printed or tried to use this as the original design works great for me, but included this version for those that may like it.
UPDATE: May 2020. A couple of users requested a version that can accept a 608 bearing. I have added a design using this bearing, however I have not tested the design. Note this will be a press fit for the bearing. A number of users have asked why the bearing is on the bottom: see the comments section for an explanation. It should be noted that that the Z lead screw applies almost zero force to this support in use when printing. It really only sees a light load when the z lead screw is turned manually using the knob https://www.thingiverse.com/thing:3373265. I therefore don't think the bearing is necessary (hence, my original design does not have a bearing), particularly as it will reduce the maximum Z range a little as the version with the bearing is bulkier than the original version as it needs to accommodate the bearing. With that said, if you prefer to have a bearing, I have provided the option!
If you make this, please post your make. If you appreciate my designs, I would appreciate a tip. It provides some encouragement that my designs are appreciated, and inspires me to post new ideas.