GearHeads Corner

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.

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

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.

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


 

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

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

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

Steve:

  Yup, just the math of the legs..
Art