Designer Needed soon

Hi
I am looking for a designer to make me custom screw tips arrowheads. I am new to 3D design and do not have the skill to make the screw section of the arrow. If anyone is able to help with the design please let me know if you can help so i can give you the details about the sizing.
Thanks

Be aware that Shapeways has a fairly strict policy about producing weapons and weapon parts. I think you'll find the information in the terms of use.

by the way, here is a really good link for seeing how to properly model the sweep profiles for screw threads..
there is some trig math there, but just look at the charts, they show you the correct proportions for each angle and surface.

http://en.wikipedia.org/wiki/ISO_metric_screw_thread

e.g.