Coil Ends

[Anonymous]

Hi All, 

I'm a bit of a newbie here - first post. 

I am trying to model a self reversing lead screw.Yesterday I created a cylinder with the appropriate coil cut, then projected the geometry of the face at either end of the coil, did a "revolve" cut of 180°, then created a counter rotating coil cut. This was all good except for the transition from the cut with no pitch, to the start of the coil and vice versa.

Today I discovered the coil ends feature to create a smooth transition from a helical to a zero pitch cut (Flat End).However Inventor doesn't seem to want to have two coil cuts with flat end (of opposite rotation) on the same part. I even tried generating the second coil with its own totally independent sketch, not using any geometry projected from the first. It will let me cut two flat end coils of the same rotation though. Any suggestions?

Otherwise Plan B will be to go back to a zero pitch cut, then increase the pitch of the coil over the first few pitches, and just fillet the corners.

Thanks in advance ,

Ryan

[salariua]

I have never designed a reversing lead screw so I might guide you wrong (I have just tryied to model one). Instead of doing a second coil would it help to mirror the first one ?

[Anonymous]

Hi,

Tried that - failed!

Thanks for the suggestion though.

Ryan