Hi BEANZVISION, this file contains only triangulated model data.

It would be easier to work on the original CAD data instead of on triangulated polygon output.

Do you have the original CAD file for this part?

If not it would probably be best to reconstruct the threads, there are some posts discussing how to model threads here:

http://moi3d.com/forum/index.php?webtag=MOI&msg=767.2
http://moi3d.com/forum/index.php?webtag=MOI&msg=490.36

Also another one here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4623.1

- Michael