[Ed Law]

Hi, we tried quite a few things and we are out of ideas. We have a very big sprocket to rotate the turret on a turntable. It is McMaster Carr part # 18635A52. The sprocket came out to be 250 teeth. The CAD model was generated in Inventor. The sprocket was made using waterjet and is 0.090 inch thick. The problem is the #25 chain cannot wrap around it. It seems the pitch of the sprocket is slightly under 0.25 inches. After about 50 teeth, the chain does not want to seat in the sprocket anymore. For most normal size sprockets this would not be a problem because it will only engage 40 teeth or so at the most. Our chain will need to engage about 150 teeth.

Does anybody have experience in making such large sprockets? Did you experience these type of problems? Please help. I have attached the CAD model.