Spline standard issue 1

[hexhamallstar]

Hi all,

I'm currently reverse engineering a spline with intent use it as a benchmark for strength. I've measured it as tip diameter = 30.5mm, root diameter = 28.5mm and z=28 (these measurements are pretty rough).

I've looked in DIN5480 and ISO 4156 aswell as ANSI B92.2M and can't seem to match it. This makes me think this is a JIS standard spline? I have a page from JIS D 2001 which states that for 28 teeth module 1 has a nominal diameter of 30mm, which is closer than the other 3 standards get!

Any help is much appreciated.

Phil

 

[mfgenggear]

hex

please post an end view picture of the spline.

Mfgenggear

 

[gearcutter]

"these measurements are pretty rough"
It would be most helpful to those that intend on helping you to, at the very least, be supplied with measurements that would not be classified as being "pretty rough".
I mean; please specify what you mean by "pretty rough"...............+/- 0.5mm or +/- 1.0mm or +/- 2.0mm?

Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

http://www.aussieweb.com.au/email.aspx?id=1194181

 

[hexhamallstar]

Thanks for the replies, i'll get a picture tomorrow and post it up.

Sorry for the ambiguity, I was using verniers so the tip diameter is going to be pretty much bang on, my problem was that the splines are crowned slightly at the ends but the vernier blades only go into the spline root up to a certain point and I'm not sure whether i'm measuring the slightly lower diameter of the crowning or if the blades are actually reaching the proper root diameter. I would say the measurements are within +/- 0.2mm, as long as my verniers were reaching the correct part.

Thanks again.

 

[gearcutter]

Go to the link below and download the PDF.
It will show you how to measure the Base Pitch.
Charts are supplied where you can attempt to match the data with your measured results.
This will help you to determine the pitch and pressure angle.
Once you've done that; then we can start to try and work out what standard you need to be working to.

http://www.artec-machine.com/_images/documents/Base_Pitch_Tables.pdf

Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

http://www.aussieweb.com.au/email.aspx?id=1194181

 

[hexhamallstar]

Measured over 3 teeth as 8.33mm, 4 teeth as 11.35 mm. So this gives base pitch of 3.02mm or 0.1189 inches.
Looking at the tables this gives a circular pitch of 0.125, but my measurement is between 17.5 and 20 degrees pressure angle (0.11921 & 0.11746).
It's much closer to the 17.5 degree value so I'm going to go with that.

How do I proceed from here?

 

[gearcutter]

If your spline is crowned; where did you take the 'M' dimension (tangential span) measurements from?
The measurements would have to be taken from the axial position that represents the peak of the crown.
Also, the span dimensions that you have shown...........are they "pretty rough"?

Ron Volmershausen
Brunkerville Engineering
Newcastle Australia

http://www.aussieweb.com.au/email.aspx?id=1194181

 

[hexhamallstar]

Those measurements were taken near the center of the spline shaft (i.e where I thought the spline was at it's 'nominal' condition), do I need to retake them at the edge of the crown?
The verniers I'm using measure down to 1/100th of a millimeter, so these measurements I would say are easily within 0.1mm.

 

[mfgenggear]

Hex

What gear cutter has provided is a viable method, but very accurate measurements must be taken.
then measurements with an Involute machine will verify if the diametral pitch & pressure angle are correct.
a mating part would also be Important to very it assembles correctly, a master spline gage would be even better.
if this is a bastard spline then it will not match any standard. which is done to discourage reverse engineering.

Here is the problem, if you are ill equipped to measure the spline for reverse engineering. wrong data can be used.
Is there a gear shop where you can take part & have them measure it with an Involute machine.
Is this for an Important part to re-fabricate or is it for a home made project.

for $300 or what ever it will cost you it would be worth it if it is a production run.

Where's my picture?

HTH
Mfgenggear

 

[hexhamallstar]

Hi Mfg,

I've attached the picture below, it's not the best quality as i'm not really supposed to be taking photos in our workshop.

The part is purely for benchmarking purposes, we are using a similar spline and would like to have accurate geometry to apply calculations to so we can figure out what factors of safety etc were used when designing the spline. It's possible we could get the spline inspected properly, if we were to do this then what information would we require exactly from the inspection?

I wouldn't like to suggest an expensive process to my boss only to tell him a week later that we needed an extra measurement that wasn't taken.

Thanks for your help,

Phil

 

[mfgenggear]

hex

picture is not very clear, but appears to be a 45 deg pressure angle.
and this spline appears to be very worn.

I would recommend the following.

# teeth, Diametral Pitch, Pressure Angle, Major & Minor Diameter, crown drop on Major, crown or straight lead, Involute,
Pitch diameter runout, Index Total Error, fillet radius at root, contour break on edges, length of spline, spline engagement.

Then spectro analysis of material, metlab samples of spline, through harden, induction harden , case hase harden.
if case harden, depth of case,Rc 50 cut off, hardness at surface. Hardness of core. This is of very importance.

HTH
Mfgenggear

 

[mfgenggear]

add Circular tooth thickness for the external,wire dia, & Measurement over Wires, & Circular tooth space ,wire dia & measurement between wires.

Mfgenggear