2D/3D Gear Design

I’m looking for a freebie gear maker, most likely in a macro form. I found this but it’s only a 15 day trial then you have to pay. [Yes, the server is currently down, I know.]

Anywho, I’ve searched far and wide for another similar program but have come up with nothing. I understand how to make a standard spur type gear, but there are some that I can’t grasp. I’m looking at miter and bevel gears out of the Small Parts Inc catalog and pulling other bits of information out of my Machinery’s Handbook to try and make the gears on AutoCAD but it is a real pain.

Anyone know of an easier way to make gears?

I talked with some people about this question and what we decided is this:

Take the pitch diameter, and create a model of the gear (hub, bore, whatnot) but instead of teeth just make a cylinder with a diameter equal to the pitch diameter.

Inventor doesn’t care about the difference. It is surely loads easier on your system (especially when you are placing/moving them . . . this can take some time on a middling machine).

So my advice is to just model the gears minus the teeth (using, again, the pitch diameter).

The point is that I want the teeth to be shown.

Perhaps putting a bitmap on the cylinder would suffice?

Perhaps you could find what you are looking for at www.cadregister.com

Ok, this is possible.

First, you need to find dimensions for each individual tooth (i.e. how far below the pitch diameter is the trough, how far above is the peak, what shape is it, etc.) and draw one tooth, then use circular pattern to draw all the teeth (after you extrude the first makes it easier) and viola.

But, you were asking about angle gears, weren’t you.

In the FIRST CAD library thread there is a link to another collection of inventor files, and they have some angle gears there. Check them out.

As I said, I’m using AutoCAD not Inventor. I want to know how to create the gear, of any size from the info given. there are no iParts for AutoCAD that I know of.

I have the following information for each gear:
Diametrical Pitch
Number of Teeth
Pitch Diameter
Mounting Distances
“D” (Base of Hub to Plane)
Hub Diameter
Hub Projection

is this what you are looking for?
most of these can be changed to any size gear by just changing a few numbers.

I, too, have been unsuccessful in finding a macro or free plug-in to create any gear you need.

What I’ve found to work best barring that is to search SDP-SI (www.sdp-si.com) for the gear I need (if it’s standard) and use their models. The models they have available for download often include one or two modeled teeth which you can then revolve around the gear and make a complete model.

Also, remember that unless you’re doing this for rendering purposes, it’s a lot less taxing on your hardware to model gears without teeth and makes mating them much easier.

Something else you can do is with a little know how, find a drawing like what is mentioned above and then tweak it with Inventor. You can create a spread sheet that you can link with your drawing. Then all you have to do to change the size of the gear would be to change a few numbers in the spread sheet and hit update and you will have unlimited number of gears for that design.

Ed Sparks’ FIRST CAD Library site (www.firstcadlibrary.com) featured/s iParts for Inventor. The sprocket and gear never worked well for me, though. The geometry of gears is a little messy at times.

The best free program I’ve seen is called “geargen” it’s some free dos type program that let’s you create gears based on a few different options, then it plots them and you can export them as a few different file types including a .dxf which will open in AutoCAD (I think).


EDIT: Just extract it to a folder and run “GG110.EXE” Other than that you might want to read the readme file to see what to do.

I suggest CAD Register.com (Thomas Register)

People please… read the original post and replys by the original poster.

I Do Not Have Inventor.
I am looking for information on bevel gears.

I almost struck gold with what M said, but the drawings for bevel gears didn’t include teeth on SPD-SI. However, those may be able to work for 2D Drawings. Clark, I have GearGen, but that works for Spur gears, which doesn’t reeeeaaaaaly help me because while a bevel gear begins as a flared spur of sorts, i don’t know the point where the tooth stops and begins because I’m only being given the Pitch circle.

Would it be possible to take all of the information that you have, create a spur gear like 2D drawing, and extrude it using an appropriate taper angle?


Possibly, but I honestly don’t know, see the gears have an odd shape, they are not actually conical from top to bottom. More like:

 /              \
 ¹---..    ..---¹   (Cut-away profile)

 /____      ____\  (would work w/ Taper Angle)

Better yet:

In looking at the bevel gear, what if the gear is created as if it were a simple taper angle. Then, for the outer angle, drawing a hollow cylinder with the appropriate taper on the inside and use subtract. For the inner angle, it would be a solid cylinder with the proper external taper and subtract that.