Hi,
I am having trouble recreating this pitch on a feed screw.
It starts with two 6mm pitch revolutions, than goes to 12mm revolutions (3 total). I can get the helix to work from 6mm to 12mm but from 12mm to 12mm always messes up the rest of it.
Below is how i am trying to set it up, not sure what I am doing wrong.
I would recommend the use of 2 separate helix features if you're looking for a sharp transition between the two pitches. The variable option will try to smoothly transition from one pitch to the next between the two steps where the pitch changes.
Thanks i think that was my issue, thinking it would make the sharp transition by default. The drawing I was trying to model for practice showed the pitch going from 6mm to 12mm in one rev.
Pretty sure you will end up wanting to have 4 rows in there
You need to allow some room for the transition between 6mm and 12mm pitch.
Currently with the 3 rows you have it will hold constant pitch through the 6mm region, then blends out to 12mm pitch the rest of the way
Then you can control also how long you want the transition to be between the two pitches.In my picture it is blending from 6mm to 12mm pitch over the course of one revolution (between Rev 2 and Rev 3) then holds constant pitch to Rev 5
For this, I use a design table, to calculate the desired transition between the different pitches. Can't attach sample, because design tables causes my SolidWorks to get stuck.
Does controlling the Height and Pitch work for you ?
The revolutions are broken numbers but if this doesn't work for you, I guess the best is to do with 2 helixes.
I would recommend the use of 2 separate helix features if you're looking for a sharp transition between the two pitches. The variable option will try to smoothly transition from one pitch to the next between the two steps where the pitch changes.