simple wooden gear design

[Mike Gregory]

Hi all,
I need to help my little one design & build a simple machine for school. I want to make something with some wooden conical gears (90 degrees to each other) each consisting of a solid wooden wheel with dowel rods sticking out as the teeth. I don't have a lot of time so I was wondering if anyone has ever designed and built something like this? I'm looking for something around 6-8" dia.

Thanks for any help you can provide,
Mike

[John Terefenko]

Mike

You can do a couple things. Go to a toy store such as toys-R-Us and you will see many gear operated toys and get some ideas from that. Or you can Google geared toys. Google is our friend.:)

[Eric DeSilva]

I ran across this a while ago... Might help:

http://woodgears.ca/gear_cutting/template.html

[Mike Golka]

Is this what you are looking for? If so PM me for Sketchup file( too large for here)

[Kyle Kraft]

Do you need to use an involute band saw blade to cut those (:D)?

[Mike McCann]

check out tinker toys.

[Cliff Rohrabacher]

Gear teeth should be shaped to transfer the drive forces uniformly and to take advantage of the strongest part of the gear tooth below the first two thirds of the gear tooth (roughly). And of course the gear tooth tip has to clear the gear it meshed with as it engages and did engages.

Which is why you see spur gears drawn with that little second taper. The idea is to let the next gear in sequence take up the strain at the stronger part of the gear tooth.

I am guessing you really won't care all that much about these factors with wood gears so just make 'em with a little taper like 5 degrees (included) or so.

[Wayne Cannon]

Legos and TinkerToys have projects that use a spoked "bull gear" like that, enagaging a "lantern pinion" or "lantern wheel" (a spoked cage), as did many of the early American water-powered mills and machinery.
http://en.wikipedia.org/wiki/Image:Water_wheel%2C_Aldersgate.JPG
http://beaversmill.ieasysite.com/new_home_page_018.htm
http://hassettmillwrights.com/StratfordHall/images/SH-Gears3.jpg
http://hassettmillwrights.com/FlowerdewHundred/images7-misc/misc-026.jpg

Although the latter shows a bull gear with more rectangular teeth, many bull gears (or cog wheels) were made with dowel, i.e., cylindrical, teeth.

[Mike Gregory]

Mike Golka, you sketched up exactly what I had in mind. In addition, I found Eric's link to gear patters really cool. In the end, I ran out of time and we made something rather simple ... but still totally cool. Thanks for your advice!

Mike