Adding Y axis support threaded rod under the Y belt

I added a threaded rod directly under the Y axis belt, because I was seeing flex in the front and back plates that the Y axis motor and pulley attach to when the machine was running. I have a Monoprice i3 V2 version, this should work on a Wanhao V2 as well. It seems to work ok, Wondering if anyone else has changed this design to have a brace directly under the belt? I see some units like the Tarantula have this better bracing of the Y axis forces built into the design, but it seems like something most could use and its simply 5 bucks worth of threaded rod at the hardware store, $7.50 if you don't already have nuts and washers to size.







How to do this (initial test, will improve process with a printed set of parts soon), for Wanhao and clones:

Bill of materials for the Y axis threaded rod:
1x 16" (or longer) 3/8 threaded rod
4x 3/8 nuts
2x 3/8 ID washers, need to be narrow outer diameter to fit between frame wire harness cutout and Y axis stepper motor L bracket. I got 22mm OD and they just barely fit, something around 16-18mm would be ideal covering the cutout but having more clearance to the motor bracket.

To install:

You will need to raise your machines frame by having Z Braces and/or some kind of feet under the frames normal standing points. It needs to be about 3-5mm higher depending on the washers you use. I use red rubber gasket material that is used for plumbing and other industries. Comes in squares, cut to shape needed, does not compress much and allows for machine leveling to a reasonable extent, it is consistent in its flatness and compression, being gasket material. I stack double layers of cutouts to get the height and vibration absorption/level stable balance I am happy with.

3/8" threaded rod fits nicely through the cutout for the wire harness on the back frame panel that mounts the motor and rails, move the wires and put the threaded rod through that cutout until it rests on the front plate under the belt pulley.

Might want to put a rubber foot on it to save your frame from slight scratching if you don't have a Z Brace part there to push on.

Install a washer and 2 nuts on ether side of the back frame panel (see pictures). Standard 3/8 nuts may slightly clip the stepper motor m3 cap screws, but can be tightened by sliding the assembly away from the stepper motor slightly. Tighten the inside nut, turn it so it moves outward (backward, however your looking at it) and pushes on the back frame panel, until you have braced your front and back plates. Do not over turn it and bend your panels outward, just turn it enough to brace the panels from moving inward. Tighten the remaining 3 nuts to hold it all in place.

This provides a direct compression resistance member very close to the motor and pulley, almost directly under the belt (offset about 2mm, but offset closer to the center of the frame due to the belt being slightly offset). I suspect it is helping my printer be a happier more stable printer, but I just installed this and have to test it out a bit.

I will be modifying my Z Braces to accommodate this new Y axis brace, allowing it to be directly at the center of the front and back panels for optimal support of the structure, as well as terminating in printed braces similar to the original Z Brace for that panel, but with vertical extensions and a mounting point for the rod. For now I have it installed raw just the threaded rod braced on the back with washers and nuts pushing on the front directly under the Y belt, but I like the results, I can't see the front and back panels moving while printing and feeling them with my eyes closed it feels like a lot less movement. Eyes closed to allow brain to focus on working senses actually is pretty OK at isolating vibrations with finger tips etc... maybe, seems like it. could be wrong.

Anyway, comments? Suggestions? Warnings?

Edited 7 time(s). Last edit at 07/12/2016 11:04PM by Milton.