By continuing to use this site, you agree to our use of cookies. Find out more
Forum sponsored by:
Forum sponsored by allandale

Sine Tables, Sine bars and calculations

Measure or define angles.

All Topics | Latest Posts

Search for:  in Thread Title in  
John McNamara08/05/2011 02:58:30
1139 forum posts
101 photos

Hi All


An interesting sine table


Made by Matrix Tool and Gauge Coventry England


The hypotenuse is 5 inches

With the top of the table level in both planes the gage block height for each axis is 3.75 inches. To set the angle or angles you place a stack of gauge blocks under the two spherical pins.


For a minute I wondered how the large radius could relate; the answer being an imaginary ball in the centre. The axis of the two small spherical locating points, located at 90 degrees to each other, pass through the centre point of the large ball segment. So as the large ball rotates the imaginary ball in the center and the two locating balls rotate also. Maintaining the strict 5 inch relationship to the two visible balls,


All that remains is to constrain the vertical axis. This is done by the 90 degree plane formed in an arc around 90 degrees of the large ball.


What I like about this design is the immense strength. Once set the large ball is locked into a cast iron pocket buy a single bolt that pulls the ball into the socket. There is a spherical coupling at the geometric centre of the large ball.


It is nice to see a design based on first principles.


I have no idea what the two small pins seen in the photo showing the vertical axis constraint do? The must have a use. Does anyone know?


I have no documentation for this find and would appreciate any feedback.
John McNamara

Edited By John McNamara on 08/05/2011 03:06:31

Edited By John McNamara on 08/05/2011 03:33:21

Nobby21/06/2011 22:59:36
587 forum posts
113 photos
May b to set a compound angle
John McNamara22/06/2011 02:31:54
1139 forum posts
101 photos
Hi Nobby
The two smaller balls on the large ball allow yo to set a compound angle.
The mystery is the two straight sided pins hidden in the slot below the ball in the middle photograph?
They must hold something.
Richard Parsons22/06/2011 09:43:07
645 forum posts
33 photos

John - I can foresee a sort of problem. The small pins that you point out may be there to stop the big ball from over rotating so you will not get the small balls up on the table. Hum Ho

Nobby22/06/2011 12:11:33
587 forum posts
113 photos
I can see them now red in background . As Richard says they may be a safety stop ?
I have used a magnetic one.
John McNamara22/06/2011 12:16:54
1139 forum posts
101 photos
Hi All
You could be right; maybe they are there to stop a balls up.

All Topics | Latest Posts

Please login to post a reply.

Magazine Locator

Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!

Find Model Engineer & Model Engineers' Workshop

Email News - Join our newsletter

Love Model Engineering? Sign up to our emails for the latest news and special offers!

Latest Forum Posts
Support Our Partners
Eccentric Engineering
Expo Tools July 14
SPG Tools October Seventeen
Allendale Electronics
TRANSWAVE Converters
Subscription Offer

Latest "Wanted" Ads
Get In Touch!

Do you want to contact the Model Engineer and Model Engineers' Workshop team?

You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.

Click THIS LINK for full contact details.

For subscription issues please see THIS LINK.

Digital Back Issues

Social Media online

'Like' us on Facebook
Follow us on Facebook

Follow us on Twitter
 Twitter Logo

Pin us on Pinterest

Visit the Model Engineer
Exhibition website

Model Engineer Exhibition