The Beall Clock Forum
General => Wheels and pinions => Topic started by: jrbeall on September 10, 2005, 08:59:01 AM

The Module system provides formulas for figuring the geometry of wheels and matching pinions. My experience indicates that a .055 Module is about as small as is practical for wood gears. With the information on this chart, any diameter may be figured. The bow clock in the gallery used .090 module. The chart may be found at http://www.bealltool.com/jrbeall/module_chart0001.pdf I think you will find it useful for designing cycloidal gears.
This chart was supplied by Damon Miller who got it from Bill Smith.

An Excell spreadsheet of Module Math based on the post above.
http://www.jtmultimedia.com/jay/ModuleMathRev1.xls
Any suggestions or ideas to make it better fould be apreciated.
Please point out any mistakes i might of made.
Also, does anybody know what to do with the Addendum Radius. Doesn't make sense to me unless it will replace the cycliodic curve. The math on the chart doesn't add up either. any suggestions.

Does anybody have formula for a cycliodic curve? I could do it the hard way with a couple of circles, but my CAD program will plot a line based on a formula if i have one.

JayRay I want to thank you for taking the time to develop and post the Excell programs. I am sure that your efforts will benefit many.

These things I already do for myself. I share with the community that has so generously shared with me. Without them I would haft to take a much longer and difficult journey. It is my hope that I don’t take from this community but rather participate.
My ignorance is great and this forum has already kick started my education rapidly. I am sure in time(even recently) we will look back at some of my post and see what a great distance I have traveled. I hope in time that I will have the opportunity to guide many along the same path.
I do, and encourage everyone to:
Concentrate on the small stuff, that’s what the big stuff is made off.
Thanx Damon

The British Horological Standards spell out the use of a regular arc which closely resembles (matches) the curve of a given cycloid. So yes. The addendum radius of curviture is used in place of a tue cycloid. I draw a circle in CAD and then move it around until it neatly joins the tooth flank a the pitch circle and the center of the tooth at addendums top.

maybe this might help
http://www.martindalecenter.com/Calculators2.html
Cleve

http://www.martindalecenter.com/Calculators1_1_CatoClocks.html#CLOCK
Cleve
[email protected]

Hi List, most people who are new to clockmaking are eventually faced with the maths that has to be mastered in order to complete a project. Don't give up, just remember that a librarian can not know every subject in her care but she can direct you to the right isle so you can find the information for your self. Same in clockmaking, there are loads of little calculations that at first seem daunting. Take each one at a time and an hour with the calculator will see some light at the end of the tunnel. Dave

JR  this chart answers many questions I was trying to figure out for myself  this saved me hours  thanks !
I did notice some peculiarities that I will post in a separate thread.
In your first post in this thread, you indicate that a module of 0.055 is the smallest practical for a wooden clock  is this in inches?

Yes, inches. My most important criteria is that the teeth can be cut with a 1/16" end mill and that the center hole can be large enough to accommodate a reasonable axle, (3/16). I have never used a pinion smaller than 10 teeth until recently I made an 8 for a motion works which seems to work fine. I suppose I could make smaller pinions with a smaller end mill.

I have an article about making your own clock wheel and pinion cutters. It has charts for cutters from .4 module up to 1.0 module and info on pinions from 6 leaves up to 16, it is in PDF format and is just over 2kb, anyone wants it call in at creedclocks(at)hotmail.com or i can send over to Mr Beal and he might post it on the site, Dave