Because I've started experimenting with BuildTak I've noticed that the quality of adhesion to this surface is very dependent on the position of the nozzle relative to the bed. So fine tuning bed height is a must to get this to work right. Because my previous Z-stop (http://www.thingiverse.com/thing:254002) wasn't that adjustable or of the right height for the E3Dv6 hotend, I needed to redesign this part. . I've posted 3 versions of different length. I use the shortest of them. . If you are using BuildTak or a similar surface, I think its really important to be able to make fine adjustments. I noticed that a 1/8 turn on the knob can make a difference between not sticking or sticking too hard. Its that sensitive. But if you get it to work, its the best surface I've used so far.This part should print fine without need for modification or support. . To assemble this, you need to reverse the orientation of the M2's Z-stop screw. You then fix the screw in place with the two nuts, giving room for the Z-stop. . As shown in the photos screw the Z-stop on the bolt and you can now finely tune your Z-stop length without having to loosen the two nuts and reposition the bolt.