mechanic of matrial

1. a screw that is 9mm to 1cm (thread diameter), but hollow/cannulated with a channel inside in center that is 3,3 mm in diameter. The length is from 150mm to 210 mm with 5 mm increments. 

2. Threading should be only in the end of the screw (about 2-2,5cm)- so the shaft is smooth and smaller than the 9mm/1cm in diameter. The screwthread should be sharp in the end of the screw.. So it can advance when screwed. 

3. 
The head of the screw should be a bit conical for a washer – which You also should design. Headhight should not be higher than approximate 5mm but it depends on the torque strength. I would also need best tension strength, the angulation of the thread and height as best as possible to get advancement in the bone and maximizing pulloutstrengt 

4. So calculations (tension strength, bending strength, pullout ) should be for 150mm 180mm and the 210 mm screws Material is Titanium high grade 5 and or surgical steel. 

5. Also the same with full threading and same specs. as above. Screwdriver is hexagonal 4mm 

6. It is fine to calculate for all lengths. Solidworks and /or autocad. Jpg files or similar also appreciated to evaluate.”