Originating an angle

[steamer]

Found this method in a toolmaking book of 1915 vintage.

I wrote a spreadsheet program to determine the diameter of a disk B relative to a smaller disk A that if sized correctly ( in the lathe) can easily create an angle to 2 minutes of arc accuracy or better. Kinda useful I thought.

Have fun.

Dave

View attachment Originating an angle with disks.xlsx

 

[steamer]

By the way....The equation is

Dia B = [(2 x (Dia A) x Sine (Theta/2)) / (1 - Sine (Theta /2))] + Dia A


Dave

 

[BigBore]

Thanks Dave! That's purdy neat. I'll stow that one away for future reference. Thm:

Ed

 

[steamer]

Enjoy...I can think of a lot of uses with small parts and small disks.

Hadn't heard of this one before...though It is obviously old hand to the old hands......

Dave

 

[steamer]

Oh and one other thing.


These disks MUST touch each other, AND rest against a flat surface....

Dave

 

[mklotz]

Hadn't heard of this one before...though It is obviously old hand to the old hands......

I guess that makes me an "old hand" then.

Download the SINE.ZIP archive from my page and you'll find two programs, SINE and SINENL.

SINE will help you to design an angle jig consisting of two cylinders separated by a link.

SINENL (SINE-NO-LINK) does the same with two cylinders butted against each other, eliminating the need for a link - a simpler construction.