Involute Spline - ASA Standards? 1

[Superslinky]

I have an old document that is incredibly hard to read but it appears there's a reference to ASA-BS:15. I think it should be ASA B5.15-1960 or 1950 but either way, I can't seem to find it. Does anyone recognize this and can help me get in the right direction? It might even be obsolete and cross to an ANSI standard which would be better for me since I already have access to that one.

Just to elaborate further, I have an involute spline and need to redraw it. There's a table that lists the following:

No. of teeth 29
Pitch 12/24
Pitch Dia. 2.4167
Base Dia. 2.0929
Actual space width .134 max
Effective space width .131 min
Major Dia. 2.580 max - 2.566 min
Form Dia 2.505 min

I still don't know the pressure angle though or how to tell what it is.

Any help would be appriciated.

Thanks!

 

[TheTick]

If you have base diameter, you don't need pressure angle. The involute "unwinds" from the base diameter, and whatever the angle is when it crosses the pitch diameter, that is the pressure angle.

 

[Superslinky]

Thanks TheTick. You wouldn't happen to have addition images to elaborate further on this would you? The image helps a bunch but I'm not sure I fully understand it.

By the way, the spec I was looking at (that I couldn't make out) turned out to be ASA B5.15-1950.

 

[TheTick]

http://en.wikipedia.org/wiki/Involute

http://en.wikipedia.org/wiki/Involute_gear

 

[gearguru]

Superslinky,
check the document

http://www.micro-machine-shop.com/gear_theory.pdf

 

[Superslinky]

Thanks to both of you. Very helpful...

 

[TheTick]

Are you using SolidWorks? I have a SolidWorks model of a gear that uses a graphical technique based on the above posts to generate the involute.

http://esoxrepublic.com/models/

Gear-A-out.zip

 

[Superslinky]

I am using Autodesk Inventor. I did have an evaluation of Camnetic's GearTeq but it has since expired. I would recommend that program to anyone that finds themselves drawing planetary gear sets....