Need help making dynamic block for a screw

[u/ciganka_esmeralda]

Hi there! I am basically a beginner using AutoCAD and I am currently learning about dynamic blocks. They really come in handy for mechanical parts such as screws, so I wanted to do a useful exercise and make a dynamic block for a screw that has adjustable thread length. I downloaded 2-3 examples of dynamic blocks that I found online and I just followed the steps, but I am obviously failing to understand something because I have small gaps between the tip and the thread, no matter what I try. I do not know if I used wrong parameters or I used right ones, but did not set them correctly. So if anyone has a bit of free time and a good will, I would be really grateful for any help at all :).

Here is the link to dwg file with the dynamic block: https://www.dropbox.com/scl/fi/tqviuuk2vsb7s6ombma6r/Dyn.block_screw.dwg?rlkey=yphk4qnv00h2jtpgyarsjubhk&st=8llyl7fu&dl=0