This is now on thingiverse as thing 214112.
This gadget moves the teflon block that glides on the back rail out on a short arm that can rotate around the original mounting point for the block. Attach a spring to the arm and anchor it to a fan screw, and now the print head can still rock, but it is held in place with more force than just gravity. Normal carriage movements that might compress the wiring harness, drag or push the filement, or just accelerate the head no longer cause any rocking, as a result, print quality improves. In my case, I think the wiring harness was the big problem because glitches were showing up on the sides of prints nearest the back of the print bed. For example, here is a comparison of the same top piece for a TARDIS printed without the spring load and with the spring load (click on the images to get the high resolution versions):
Yes, it is different filament, but I don't think that made the difference. All the irregular lines of filament wandering outside the proper print path are gone. This little gadget makes a world of difference.
The part looks like:
And goes on the solidoodle like:
The cylindrical bit goes where the teflon block was, and the teflon block moves out to the end of the arm where it is held in place with a 15mm M3 bolt and nut. The spring is looped through the hole next to the teflon block and goes up to (in my case) the top corner bolt holding on the fan. The spring does not apply a lot of force (you probably don't want a lot of force), but is is clearly enough as you can see in the print comparisons above. This spring came from a spring assortment I picked up a while ago at Home Depot.
Once I switch to the new carriage with linear bearing, this mod will no longer be needed.
Go back to my main Solidoodle page.