ANSI B92.1 involute spline form diameter tolerance 2

[Engineering Saiyan]

I have a general question about how the form diameter is tolerance on an involute spline per ANSI B92.1-1996.

I am trying to determine if a minor diameter non-conformance on an external spline could affect the interface between the mating part by eating up the form clearance.
Form diameter only seems to be mentioned as a basic dim but can't find out how it is tolerance.

If specifics are needed we can assume a 30 deg fillet root side fit, 10/20 with 60 teeth.

Any help would be appreciated, thanks.

 

[mfgenggear]

The form diameter also know as True Involute Form, (TIF) is basic, however here are some tips.

I consider the TIF as a max on externals
and a min on internals. (Gear or Splines)
a) the root diameter fillet radii is often specified as a minimum.
however the fillet radii can not violate the the tif because it will cause interference.
b) if the spline accept the go gage, there is no interference and will assemble.
base that to accept the non conformance.
if taking a manual involute verification with a gear involute checker the start of the involute check will be the basic TIF (form).
and must past the requirement to the spec. if no gages are available.

 

[spigor]

For an external spline ANSI B92.1-1996 gives you the Form Diameter D[sub]FE[/sub] and the mating part can reach to that Form Diameter (plus some margin). It means that the tolerance for D[sub]FE[/sub] is "max".

 

[tbuelna]

ANSI B92.1-1996 section 25 gives some guidance regarding minimum form diameter limits of external splines.

 

[Engineering Saiyan]

Thanks for the responses, I wish it was more explicitly defined but what you guys are saying makes sense.

Also paragraph 25 is only for modifications for low numbers of teeth, but not applicable in my case.