If you search treatise on milling on the internet archive 2 ebooks will be found. One by Cincinati and the other by Brown and Sharp.

Old but gears are gears.

John

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Page 155 onwards in the B&S:-

**LINK**

I have a spreadsheet  for designing parallel depth gears with the sin / cos error fixed.  I built this a few years back to make some gears for my Stuart Victoria.

The calculations are primarily from the Ivan Laws book,  but then I have another book by Franklin Jones,  which I used to tweak a couple of parameters.

This should work for you:

https://www.dropbox.com/s/gkb3w2lfmlig8oa/Gears_Final_180410.xls?dl=0

You do not need to register for dropbox or need a login to access.   The worksheet is previewed,  but there is a "download" button in the top right hand corner of the screen.

Steve

Edited By Steve Withnell on 04/11/2015 20:09:38

Edited By Steve Withnell on 04/11/2015 20:12:30

All – thank you for the email – especially Steve for his spreadsheet. I do have two sets of bevel gears to cut (for a Heisler locomotive) if/when I get to it in my workshop todo list… I do have Ivans book plus a bunch of others, but I like the simplicity of Ivan's parallel depth gear example.

John.

In my 1988 edition of Ivan Law's book, both formulae on page 106 use sin, neither using cos. Should both change from sin to cos or just the one for the small end?

Doug

Gentlemen,

If the gear angle remains at 45 degrees for the bevel gear in question, as the example shown on page 106, then cos 45 and sin 45 have identical values of 0.707 [ square root of 2 divided by 2] and the actual term used doesn't matter

I will look and see what my other reference books suggest and report back on bevels having other angles.where the trig function chosen has more influence. It is not difficult to change though since sin x= 1/cos x and vice versa and the values can only vary between 0 and 1.

Brian

.

Thanks, Steve

That looks like just what we need !!

… This may save you some effort

… Not sure if it gives access to all the relevant pages.

MichaelG.

Ok, as far as I know SIN has to be changed to COS in the two upper formulas, not the lower one. This is a scan of the page from my copy with my scribbles on it.

As Rod pointed out, I have produced 2:1 gears using them and the results are shown below.

Neil

Thanks Michael for saving me scanning the book!

These are the gears I cut for the Victoria using the parallel depth method.

**LINK**

Regards

Steve