Hi, James.  I don't if this recent Area thread would be of any help... Area thread: modeling bevel gears.  Here's a quick demo I put together on modeling a gear from a star shape... star shape for gear.  I'm not aware of any plugins that would figure this stuff out for you. 

I suspect this may be one of those cases where Max can't duplicate real-world physics, i.e. actually having one gear actuating a second one.  There are a number of places on the 'net that have gear ration converters, so you'd manually animate each gear, for instance gear A rotates 3 times for every 1 rotation of gear B.

That was pretty cool for the modeling part But I understand your question I had placed a similar thread some time ago I was still not able to figure it out for max but you need to visit the CAD thread it can be done in CAD or Inventor using constraints as for the modeling it is a bit more precise but it works. And then there is some script I found one day  for Maya "Gear Generator" Never tried it though I might try it this wekend and if it does work I will try to export it as an Obj and see if it could be imported but from previous experience you know there may be a chance that the formulary for Maya will not work or be either importable or exportable. I will let you know either way though.

Thanks for the link,

That is good, I think the maths involved is good for the brain rather than a more lazy point and click solution.

shame I cant seem to download it and back it up for later offline reference.

If it's of any help, here's the text from the tute describing the math...

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SPACING THE TEETH

In order for gears to mesh properly, the spacing of the teeth on all of the gears has to be the same amount.  Here's how to compute that spacing.

The spacing, or width, of each tooth is equal to the inner circumference of the gear divided by the number of teeth.
          
                   spacing = inner circumference / tooth count

The equation to find a circumference is circumference = 2(PI x radius), where PI = 3.1416.  The inner radius of the star spline is 100, so...

                  circumference = 2(3.1416 x 100) = 628.32 

That makes the tooth spacing...

                  spacing = 628.32 / 20 = 31.4 units

The second gear has 12 teeth, each 31.4 units wide.  So multiply 31.4 by 12 to find what the inner circumference needs to be.

       inner circumference = 31.4 x 12 = 376.99 = 377 units

But we need to know the radius.  The equation for that is...
  
               radius = (circumference / PI) / 2

So the inner radius is (377 / 3.1416) / 2 = 60 units.     Recall that the outer radius of the first gear is 40 units more than the inner radius, so the outer radius of this gear will be 60 + 40 = 100 units.

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GEAR RATIOS

The gear ratio describes how much one meshed gear turns in relation to how much the gear it's meshed with turns.  The gear ratio is calculated by dividing one gear's circumference by the other gear's circumference.  If gear "A" is 10 units around and gear "B" is 5 units around, the gear ratio of A to B is 1:2, and the ration of B to A is 1:0.5.  Either way, gear "B" will make two turns for every one turn that gear "A" makes.

If you know the number of teeth on each gear, finding the gear ratio is just as simple; divide the number of teeth on one gear by the number of teeth on the other gear.

gear ratio = tooth count "A" / tooth count "B"

In this demonstration, gear1 has 20 teeth and gear2 has 12 teeth.  The ratio of gear1 to gear2 is 20 divided by 12, or 1:1.6666666... on forever.  We could round this off to 1:1.67, but every time the gears rotated there would be a slight error that would start to add up over time.

Let's try it in the other direction.  The ratio of gear2 to gear1 is 12 divided by 20, or 1:0.6.  This is much better.  It means that for every full revolution that gear2 (the smaller gear) makes, gear1 (the larger gear) will make 0.6 of a revolution. 

 

Happy to oblige.  It's nice to run into another ideator.  If you're in need of any other conversion equations, like where the only known value is the gear ratio, give a holler.

Hey B, Let me start off by wishing every one a very good Thanksgiving if I do not speak to you before the Holiday.

I tried to save your email address in my address book for future ref but it will not let me save it because of its format. So if you would could you send me the formulary docs you were going to send James. Thanks particleone@hotmail.com just put what its about in the subject

Hi Bruce. yes, I have the same user name. Only one old post though...

Sorry. Double post...

Cool idea, Andy.

once again bhnh, you amaze me with your knowledge of Max.  Your mesh modeling for the gears in your tutorial was inspiring.

Hey B try image12@verizon.net