How to extend a screw thread?

 From:  BEANZVISION
11740.6 In reply to 11740.5 
Hi Michael,

Thanks for taking the time to have a look. I don't have any specs on this at all. The file was included in a 3d printing job. I had to modify a part to be larger which resulted in the screw being too short. Yours looks extremely close so I will try and do a test print to see if it fits. :)