GearHeads Corner

Hi Art,
This is probably backwards to what most people want from Gearotic, but here goes!

I make lots of gear combinations that if fit of 4" by 5" blocks I call them "Fidgets"  (I was making them years before the spinner fidgets came out)  For most of these Fidgets I can use my deputing gage to get a good "loose" mesh on the gears and they sell well to young and old at a Farmers Market.

One of the Fidgets I have trouble with is a block of gears.  I can make a block of nIne gears without too much trouble, however I'm trying to make a block of 15 and I can't get the meshing predictably loose enough that guarantees that a child can work them.  Currently I'm using the boxing function to give me the arbor spacings and it works, but with cumulative errors and wood being what it is the finished product will not turn freely.

Is there a way to increase "backlash" to make them set looser?

Hi John:

  Gearotic 1 used to move the shafts slightly, but Ive found the math
works better if you simply widen the tooth spacing, that allows a bit of slop in
all directions.. Just change form 50% to 49% and see the effect in simulation.

(Nice looking block.. :)

Art

Hi Art,
I did as you suggested and changed the tooth width to 49% - I could not detect any difference in the simulation (maybe my screen?)  Anyway I changed it to 45% and then I could see a difference.  I cut a set of 15 gears and they work really nice and freely.

I took the old binding set and made the centre hole 1/32 bigger and now that one works as well - certainly not as elegant as your solution but it does work.

Here is a photo of the 45% set - kind of wildly coloured but will be a hit at the market.

Thanks for your help

Hi John:

>>Anyway I changed it to 45% and then I could see a difference.  I cut a set of 15 gears and they work really nice and freely.

  Good to hear. It is not a very sensitive adjustment as the additional backlash
is a cosine function of the tooth width so its slow to take off as you adjust
downwards in width, but I too find 45% to be about right for such projects
and when I do wooden gears I lower it to at least 47% just for wood swelling
and such over time. Glad to hear it worked out.

Art

We need a like button for the forum :)  Looks nice, John!  Is that only a 4x5" block?

Would the same type of project work with eccentric gears?

Kirk

Yes the block is 4? by 5.25?.

I haven?t tried the eccentric as a block, so that is a challenge!!

I can simulate a 2x2 array with 4 sided gears, 3 sided was a bust.  I need to go back and review the doc videos to relearn how to get shafts exactly where I want them then give it a try with some 1/8" plywood that's sitting here going "Cut me, Cut me"

Kirk

If it will simulate then boxing will give you the shafts