Standard Spline 3

[nacho911]

I am reverse engineering an internal Spline. It has a major Dia. of: 2.75" (69.88mm), a Minor Dia of 2.574" (32.696mm), and it has a 30° Pressure Angle. I have been unable to find it in the ANSI Standards. Can anyone confirm weather or not this is a custom Spline, any advice or direction would be appreciated

Cheers,
Aaron

"The Liver is Evil it must be Punished"

 

[mfgenggear]

nacho911

what is the #teeth, fillet or flat root

 

[nacho911]

30 Teeth, Flat root

 

[mfgenggear]

Nacho

are you sure this is a spline?

can you take a base pitch measurement.
cord accross 2 & 3 teeth and subtract the diff.

do yo have a optical comparator?
measure the approx. circular pitch?

 

[nacho911]

Approx base pitch is .334". I do not have an optical comparator.

 

[mfgenggear]

Nacho

according to base pitch charts

.338 base pitch = 9DP 14.5 Deg PA
.329 base pitch = 2.75 Mod 14.5 Deg PA

to be absolutly sure, is there a gear shop in your area?
have them run an Involute chart.
The involute will be straight if the pitch & pressure angle are correct.

That is the best way to verify the spline or gear geometry.
I have made custom gear geometry that are used for a splines.

 

[nacho911]

I am trying another approach. hass anyone heard of GB3478.1-83 Class, Module 2.25

 

[mfgenggear]

Nacho

Nacho i google it, standard 2.25 Mod 30 Deg PA
Need more Info on your question?

Take care

 

[ChrisDuncan]

Google

"70mm spline" gets 7 hits

"2.75 spline" gets 1 hit

are you sure it's not ISO?

2.574" = 65.379mm

32.696mm is the radius?

 

[nacho911]

I have obtained an Involute Spline standard GB3478.1-83. It's in chinese. It consists of various Class/Modules:
.5, (0.75), 1, (1.25), 1.5, (1.75), 2, 2.5, Etc . .

One of my previous colleagues. Described the External Mate to this Gear/Spline, as Class 2.25. Which is not in my copy of GB3478.1-83, however my dimensions do put my gear in between 2, and 2.5

 

[mfgenggear]

Nacho

it appears the base pitch submitted is off.

this appears to be a profile, reduced gear.

25.4/2.25= 11.2888889 DP

30+1/11.28889DP= 2.74606299 OD

however the only way to verify it is to check it in an Involute Machine.

Duncan

not sure about your statement.
I googled the GB3478.1-83 because I do not have this spec.
it the reply obtained was 2.25M 30 PA

 

[ChrisDuncan]

Just thought maybe it was metric.

 

[nacho911]

I took my spline to a gear manufacturer, and his jaw dropped. He said it was a type of Stub Spline. and assured me it was not close to any standard. thanks to everyone who contributed to this thread!