helix driven feature in an assy

I've been trying to build a spiral staircase in an assy, based on a steel column, with hole fixtures drilled along a helix curve (up to there OK) If I build the stairs into the part, no problems.
Now when I make the steps separately, and try to drive them up my column with a feature driven pattern (using my drill curve on the column) I do get a spiral stair, but not at the right diameter, and not centered on the column.
I was figuring on doing a multiple config, and I use combinations of wood and steel, so an assy seemed much better, but no way to work it. It feels like a mate conflict, but it may be inherent to the helix.
Any ideas will be worked to death on reception, thanks

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5 Answers

Hey Cliff, check out the solution here
http://www.youtube.com/watch?v=5Ee8GkWDkus
it involves properly orienting the column

SolidWize.com

 
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Thanks Rohit Mitra for your quick answer, I haven't had time to reconstruct, but it still will need a workaround.
You correctly drove your fixing hole using a coincident plane, getting what seems to be a real perpendicular to the column (rod), I used the helix, extruding from the front plane so as to be able to control the height of the first stair (not being able to constrain the helix base).
Your solution does work though, which is reassuring, I'll dig my nose in today to figure out an elegant way to contol and adjust step height/distance.
Angular positioning is possible, but tedious, since the first step is not at the bottom of the column, and follows the helix (generaly 1, or 3/4 of a revolution on entire height)
a good day to you

 
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Need some help here, Rohit Mitra's assy works, and mine won't. I'm still getting an offset from the central column, even after sacrificing my starting point (preferring a original sketch plane perpendicular to "right plane" for test purposes)
I've played around with several mate types for the first step, the included file is missing the flat coincident on the guide rod, but the result seems identical.
If I insert the following steps manually, I get an error on the step to column concentric mate, either not paralell or not concentric, usually with 0° or 0mm difference. This seems to indicate that my holes are not correctly tangent to the column. It can be built using a concentric mate between center of curve edge of step to column, without visual evidence of offset.
I have tried to correct this several ways without success.
Changing step shape at mate point changes the offset (I haven't figured out the relation), as does changing mating rod to flat or double.
Using the hole wizard gives same sort of offset.
I'm stumped, I'm missing something somewhere and can't find it, it's not messing up my sleep, but any help would be very welcome.
best wishes from France

 
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Thanks, Rohit, you are a blinding flash. You kindly pushed my nose into something that was probably causing anomalies in the past. Guess I should put the bible back on my nightable and go fishing for those details.
I certainly owe you one, no way I would have found it without your help.

 
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