# Transformation of 8mm straight motion to 210 degree motion

Everyone.

I want to make the transformation form Straight motion to Rotational motion ,like [this].1

But it did not work. Probably, this was mistake of Groove size　on spiral groove. But I thought I must know the formula between red arrow and blue arrow of this mechanism.

So Would you tell me the formula of this? And Any clue for this mechanism welcome.

Thank you & Sorry for poor English in advance .

• Can you provide some more details about your goals with this? Is this supposed to transmit considerable forces? Minimize any slack in end positions or between them? Use as few parts as possible? Is linearity a concern? How fast is this supposed to move and how frequently it cycles? Which part is the driven one? – TooTea Feb 1 at 8:20
• The problem with this implementation appears that the torque necessary needs to be generated by a sideways force, orthogonal to the (red) direction of movement. The groove is angled only very slightly, which is how this theoretically should work. But in engineering, we don't have the rigid, frictionless objects which we can assume in physics. – MSalters Feb 1 at 10:38
• Thank you,TooTea.This suppose to transmit around 80 kgf·m/s.Minimize any slack in end positions →Yes.Use as few parts as possible→Yes.Is linearity a concern→Yes.This supposed to move 3 seconds and onetime at every time you use.driven one is groove circle one. Sorry for poor explanation. – setuko mori Feb 1 at 14:04
• Thank you,MSalters.Is it true that orthogonal to the (red) direction of movement is needed?Then , 507movements.com/mm_094.html or 507movements.com/mm_099.html is fake? – setuko mori Feb 1 at 14:26
• In both of those animations the spiral is driving. The linear drive is being driven. The system is not reversible because the angle on the spiral is far too shallow. – Transistor Feb 1 at 16:08