sprocket boss doesn't chane

[Stephen Fornelius]

Working on my clock sprockets again.  While making the 1st sprocket, I tried to change the boss size to something smaller, however it doesn't change at all.  Regenerating doesn't work on it either.  The leg and rim functions work fine.

[ArtF]

Hi Stephen:

  I didnt think Boss was on separte code. Is this Sprockets or gears and what type? Do you mean when you respoke
on the project screen?

Art

[Stephen Fornelius]

This is when I'm doing an 84 tooth #25 sprocket.  I want the center to be smaller that what's shown.  I have the legs at 15% and the rim at 15%, and they change immediately.  When I put in a different shaft hole, it takes a refresh to bring that hole to size, but when I do anything to the boss%, nothing happens at all.

[ArtF]

Steve:

  Hmm, hen I try that the boss changes things quite a bit, and when I enter a new shaft diamter.. say 8mm, it changes when I press enter.. The Boss ratio can be specific to the spoke type though..what kind of spoke is it.?

Art


 

[Stephen Fornelius]

I'm doing an 8-spoke tapered leg sprocket.  I'm going to have to put a hub on it to stabilize it, so that's why i want to be able to reduce the size of the boss so I can mate it to the hub (which I attach with 2 socket head cap screws).  The first one i did was pretty wobbly on a 3/8" shaft, and the hub helped a bit, but it was still not tracking straight.  When you have a roller chain moving and the sprocket is wobbling, the chain gets hung up on the teeth.  I also have a toothing issue - the chain doesn't want to lay down properly, but this could be due to any number of things I was experimenting with, like taking the .dfx over to BobCAD to cut away half so my TAIG mill could handle a 7" sprocket.

Steve

[ArtF]

Hi Steve:

  Ahh, I see now. The reason is that the boss is limited to 25%, but in a 8 leg taper the boss max is less than the
intersection point of the tapers. SO the boss cannot be made large enough to affect the drawing. Set to 4 legs and youll see
what I mean as you adjust the boss. Id try using standard as without the taper the math does seem to allow for a larger boss...

Art

[Stephen Fornelius]

Art,

OK, I understand now -the bases of the legs is bigger than the boss I wanted to make, so it can't do it.

Steve

[ArtF]

Steve:

  Yup, just the math of the legs..
Art