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Help! New Engineer Need help identifying CV shaft spline standard
9

Help! New Engineer Need help identifying CV shaft spline standard

Help! New Engineer Need help identifying CV shaft spline standard

(OP)
Hi everyone,

My first post here. I am a young engineer and just got my first job out of college as a design/reverse engineer for a aerospace company. Currently I am doing my own automotive projects on the side and having trouble identifying this spline. Long story short, I am retrofitting tapered roller bearings into a hub and spindle for a old Isuzu. I have virtually everything complete besides matching this spline standard. I've been beating my head on this part for a bit now, and would appreciate any insight. Also I can't find a copy of any JIS spline standards that don't cost upwards of +$350!

Pics attached too.

I am pretty sure it is JIS-D-2001 or JIS 1603 B. Although it is probably a JIS-D-2001 because its a cv shaft, meaning major diameter fit. I could be wrong about it being a JIS standard because my research points out that GM had a lot to do with building this car.

Spec/Dimensions I've found below via optical comparator:

Internal Spline
24 Teeth
Small ID (tip to tip): 0.975"
Big ID (root to root): 1.06"
Tip width : 0.027"
Root Width : 0.017"
Angle of tooth (paint drawing attached for clarification): 40-50 degrees




RE: Help! New Engineer Need help identifying CV shaft spline standard

I think you may need to take some measurements between pins. Using several size pins could also help determine if it is an involute or not. Although if it's GM there's a decent chance it's not a standard spline. I would recommend reading up on involute splines so you know what you're looking for with major/minor diameters, circular space width, and pressure angle etc.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
Thanks lfw618. I am familiar with the 3 gauge pin method, but only for something external, I only have the internal spline here. I could track down the CV shaft and do it on that.

Why since GM it won't match a standard spline? Do they have their own spline standards or something?

RE: Help! New Engineer Need help identifying CV shaft spline standard

Measurement between or over pins is just two pins. Again I think you would benefit from reading up more on involute spline terminology. There is a lot of information readily available on the internet without needing to buy a standard.

Automotive is one of those industries where non-standard splines are often justified. GM often uses non-standard splines in their drivetrain parts in my experience.

RE: Help! New Engineer Need help identifying CV shaft spline standard

Yeppers that's a spline all right ,
3 wire check wont work , only two wires since truncated
obtain dentist two part mold, and cast a mold or if you can
measure circular pitch, and with the mold measure the base pitch.
look at charts for combination to get a Module or DP. that has the same CP & Base Pitch..
it looks like a 45 deg spline.

do you have access to a CNC gear checker?

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
Thanks mfgenggear! I am working on getting the mating CV/axle shaft which should be in my hands soon (a nearly brand new one.. super lucky!).

No access to CNC gear checker unfortunately. I do have access to optical comparator, vision system, and x2 CMMs.

I will come back with my results soon.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
I have attached more pics of the spline too for reference.



RE: Help! New Engineer Need help identifying CV shaft spline standard

There used to be a guy around here, known by the name of gearcutter /Ron Volmershausen, Australia/, very knowledgeable when it came to the JIS spline standards, but he seems to be no longer with us.
There is only one involute that meets all the conditions you have mentioned, so I have calculated it.
Check out this template 10:1 https://files.engineering.com/getfile.aspx?folder=...
You may want to print it out (or some section(s) of it) in a scale matching that of your optical comparator and see if it fits, and let us know.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
Hi everyone,

Sorry for the delay. Also thanks spigor! I'll give that a shot next week.

I got the CV shaft in (male mating spline) and did some over pine measurements. I will pop it on the vision system tomorrow to confirm #'s but I thought I'd share the raw data (+/- 0.00005"). Again any insight is greatly appreciated. I will crunch numbers asap and post findings here:

1) Pin one dia= .1199" , Pin two dia= .1199" --> 1.2246" across/ 1.22495" across
2) Pin one dia= .1080" , Pin two dia= .1079" --> 1.1973" across/ 1.19735" across
3) Pin one dia= .09200 , Pin two dia= .09200" --> 1.1605" across/ 1.1601" across
4) Pin one dia= .07190" , Pin two dia= .07195" --> 1.11320" across / same
5) Pin one dia= .06290" , Pin two dia= .06295" --> 1.09135" across/ same
6) Pin one dia= .05485", Pin two dia= .05485 --> 1.0726" across / 1.07300" across
7) Pin one dia= .04480" , Pin two dia= .04485" --> 1.04770" across/ same

Pictures:
1)
2)
3)
4)
5)
6)
7)


Thanks again everyone.

RE: Help! New Engineer Need help identifying CV shaft spline standard

Ok I take it back, that's probably a standard spline. Those measurements seem consistent with a 24DP 45 degree PA. Have you been able to calculate circular tooth thickness from those measurements? I'd look at getting ANSI B92.1 to confirm. With calculated tooth thickness and the standard you can guess the tolerance class (maybe class 6?).

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
Sorry all,

Got the flu and been sleeping feels like for 3-4 days straight. Anyways Thursday I remeasured the female spline on the vision system and comparator to match numbers; my initial measurements were off.

Diameter Root = 1.0627"
Diameter Tip = .9761"
Tip width = .0274" (across treated as straight line just for calculation sanity checks)
Root Width = .0168" (same; across treated as straight line)

Angles of teeth I obtained below in the figure:


--------------------------------------------------------------------------------------------------------------------------------
As far as calculations go, I am going to go ahead and bite the bullet here, and look stupid on the internet. The only calcs I am confident with are with module and pressure angle. I didn't to mention that I am up to speed with gear terminology because I was also working on a custom gear project for my Mazda prior, however little reverse engineering was involved, yet.

PA = 45 degrees (calculated via male shaft physical measurement and CAD model female spline measurement to confirm via method here: https://www.geartechnology.com/issues/0819x/spline...)

Circular pitch = 1.0194"... is it fair here to take the circle directly between Diameter Root = 1.0627" Diameter Tip = .9761" if PA is 45 degrees?

Module = .042475

As far as measurement over two pins; I am very lost here. I can't confidently follow the math in write ups online because most call of a known pitch, which I don't have. ANSI B92.1 is close to $100, and I am hesitant to buy another standard I'll maybe not need or use much (last time I spent $300+ on standards I barely needed for my gear project).

I am not asking to be spoon fed (unless you want to haha) but maybe a sample calc from the data I provided?

Also I was thinking since this spline most likely be EDM'ed, I can provide a drawing (similar to spigor provided above)and run a test cut on a 1/4" plate. Then I an test fit on the CV shaft and see if it has similar backlash and fit.

Sorry for the long post everyone. I am getting a little desperate as my business partner for this project seems to be loosing faith.

RE: Help! New Engineer Need help identifying CV shaft spline standard

Check the calculations/reverse calculations on this site:
http://zakgear.com/

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
Thank you! I've gone through this website as well. I was confused by this term: "Helix angle on pitch diameter". Can you shed some light on this?

I was looking at this calculator/calcs: http://www.zakgear.com/Over_Pins.html

RE: Help! New Engineer Need help identifying CV shaft spline standard

For reverse calculation (tooth thickness from the size over pins) check this:
http://www.zakgear.com/Over_Pins_Reverse.html
Splines and spur gears have helical angle zero; for the helical gears it will be non-zero value. Because the helical angle changes by the diameter, both the angle and dia where it is measured is important for the calculations.
But this helix stuff was just my "spoon" of generic info for you. For the helix angle entry you need to enter there 0 (zero).
Another "spoon": The pressure angle of a spline/gear is defined at the PD too, because it too differs by the dia... Confused enough?
Please be aware that all of the discussion and calculations mentioned here are valid for involute splines.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
gearguru,

makes plenty of sense. I'll report back soon.

RE: Help! New Engineer Need help identifying CV shaft spline standard

can you measure the major dia of the male spline and let me know if it measures between 1.042 / 1037 also could you take a measurement across seven teeth and let me know how close it is to .7583 / .7574. Your initial measurements are pointing towards a ANSI B92-1-1970 (revised 1993) Table 57 Class 5.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
Yes my OD measurement is what you got there. thanks!

RE: Help! New Engineer Need help identifying CV shaft spline standard

Google search a web site that will create a free dxf file of the internal spline geometry.
Open with a cad compatible. And blow it up
Print out on clear glassine (clear transparent plastic for printing)
Throw it up on the optical comparator.
Inspect the internal spline.
Use the same power as the template printed.
Verify if the pressure angle is close.
The printer driver must be set to scale.
See if the involute is close. It may also be SAE J spline. Automotive.
I have a page copied from my SAE handbook.
Tomorrow I will show it up here.
If the involute is close you now know the Diametral Pitch, and pressure angle.

The base pitch can be calculated to Diametral Pitch (DP).
If you have the correct #t, DP, & PA
You will get the correct involute.
You must have the above correct data
For Correct Measurement to Circular tooth space for internals, and tooth thickness
External. Splines are normally have an effective tooth thickness for externals
And standard tooth space for internal.
Is usaully (pi/DP)= circular pitch then divided by 2 = standard tooth thickness.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
THANK YOU!!!!!!!!!!!

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
mfgenggear that pdf you shared only has it for 36 or 48 teeth, or "serrations" as they call it. Am I missing something here?

RE: Help! New Engineer Need help identifying CV shaft spline standard

nope sorry about that but the formula applies just the # of teeth, stick with the asme b92.1

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
Hi everyone,

So I think I'll go with a Mylar sheet drawing and pay for that service. However I can't seem to find a trustworthy/ legit website to convert my involute spline geometry to dxf file. I've started to model it in Solidworks but not sure it'll come out right. Would love to check my work.

RE: Help! New Engineer Need help identifying CV shaft spline standard

How are you modeling it? Do you have the points on the involute flanks calculated?
Years ago I created an OpenOffice spreadsheet for a friend to do just that. He then used the calculated coordinates to create a "script" (in DraftSight) to draw the curves and completed the tooth geometry (root, tip arc) "manually" and used it in wirecutting the gear.
I don't have access to any CAD anymore, but I think that Solidworks has some scripting or user's programming tool too.

RE: Help! New Engineer Need help identifying CV shaft spline standard

If you're using Solidworks, you can model the involute curve with a parametric equation driven curve. x=BR*(cos(t)+t(sin(t)) y=BR*(sin(t)-tcos(t)), then mirror that around a line to .5 of your circular space width to get your spline tooth.

RE: Help! New Engineer Need help identifying CV shaft spline standard

Do you want a dxf file with that spline from us? You suggested you had access to an optical comparator at work even though it is your personal project- why didn't you tell us if my sketch matches the actual part? Assuming it does, do you want a dxf file of:
a) an involute spline calculated from your second measurements, i.e. of my sketch,
b) an involute spline corrected to standard B92.1 with loose fit as indicated by your measurements, possibly resulting from wear, or
c) an involute spline as per B92.1 Class 5, tighter, but you can always run another WEDM cut if it's too tight?

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
spigor: If you could do a, b, and c that would be awesome! I'd owe you a steak dinner haha. I haven't sent your original file out for printing yet because I want all three. Also keep in mind I have limited access with work machines for personal projects; don't want to stretch these freedoms and get fired.

lfw618: cool thank you! I will give this a shot this weekend.

gearguru: I have two angles posted above, and root diameter and tip diameter. Isn't this enough to full define it? I know my #'s are accurate about .0045" differences max when comparing them to comparator and vision system. Again I took three measurements per machine and took average.

If I can model them like I described above, convert it to dxf on solidworks, and then and pop in spigor's dxf file, that would be another way to compare, yea?

Again thanks for all the help everyone! Learned so much through this process.

RE: Help! New Engineer Need help identifying CV shaft spline standard

I used the following data to model the tooth geometry:

module or diametral pitch
# of teeth
pressure angle at pitch dia
tooth thickness at pitch dia (which is measured as arc length)
major dia
minor dia

Then you will also need to model the root geometry so that it does not interfere with the internal spline.
(Be aware that those tooth thicknesses in posts above are measured/calculated as the arc lengths - portion of the pitch circle which runs between the two flanks!)

I trust spigor, he knows what he is doing.



RE: Help! New Engineer Need help identifying CV shaft spline standard

also if you believe the data is correct I can also create the DXF file
perfect for EDM

RE: Help! New Engineer Need help identifying CV shaft spline standard

@gearguru
Thank you

Speedracerfast, Speedracerfast
Here is a dxf file with an involute spline profile calculated from your initial measurements, and it also contains a spline profile based on your second measurements corrected to standard B92.1 Class 5 (pink):
https://files.engineering.com/getfile.aspx?folder=...
The fillet should WEDM ok, but if not you need to decrease the major diameter and therefore to increase the fillet radius.
Here is also a pdf version for reference:
https://files.engineering.com/getfile.aspx?folder=...

RE: Help! New Engineer Need help identifying CV shaft spline standard

2
Well, mfgenggear is a very reliable source and "old" and knowledgeable member of this site too.
Actually everybody in this thread brought interesting and valuable input.

@mfgenggear : Thanks for the interesting links. The geargenerator web is nicely done, but does not allow to enter the tooth thicknesses and does not create the internal gears. Therefore before the dxf file created there is used, has to be properly edited. If the involutes created there are properly calculated is a question too, we do not know the calculation methods used there. It is also interesting, that the inch based system (DP, not the metric, module) is used there - that site was obviously created in the Europe.

RE: Help! New Engineer Need help identifying CV shaft spline standard

I played with the geargenerator again. There is the option to create the internal gears as well. (in gear properties click on the box "internal". I was wrong in my previous entry.
Very clever program. Now I'll check if I can enter my own major and minor diameters...

RE: Help! New Engineer Need help identifying CV shaft spline standard

Hi @gearguru
Yes the site needed vetting.
For accuracy.i can not take credit for
Online gear generator. It belongs to some one else.

I can create dxf files that are very accurate. I had parts were wire Cut gears and splines and we're verify with CNC gear checker to be with in .0004 involute tolerance.

Also let me reciprocate the thanks.
I have learned so much from other posters as well
I try to verify any calculations or programs with each other. Correct calculations should agree with the same results. I like using old dos programs that have worked well over the years plus I have written my own and vetted them as accurate.
By testing and verifing my results.

Just as my days working in the shop.
Measure 3 times, then cut.

RE: Help! New Engineer Need help identifying CV shaft spline standard

@mfgeggear: I sent an email to the owner of the geargenerator, I believe he is in Hungary. Obviously he is a very skilled programmer.
My calculations are mostly done in a spreadsheet, but in the past I also tried to create some simple programs in VB. They still work. Now I am retired and only occasionally look here. I like to help young people as long as they are anxious to learn how to solve, not just browse and look for ready solution of their problem. This is the case in this thread.
And I agree - if I can not verify/duplicate what some people calculated, I do not use their calculations.
This is a good thread, it demonstrates how are people able to help each other.
@Speedracerfast : You have two excellent sources for your dxf's; compare it and decide what to do next!

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
Wow thanks everyone for the help! Once again I appreciate the knowledge.

As for my last post, what I meant to say was "fully define" the spline the way I measured it described above, then use that model to measure other features that are spline specific. I know I need more info to put on the drawing, hence why I came here for help ;). Turns out it won't work well doing it this way anyways.

Now it's time to compile all these up, check calculations (as you all recommended). Because I'd like to know how to do this myself in the future; very useful skill to have.

If it doesn't break my NDA, I'll post some prototype 3D prints that come in soon. I also changed my bearings for the 100th time, and sourced a similar bearing (automotive specific.. same bearing used on many other cars today). Now I can copy pre-load specifications and have confidence for 70k-100k mile life.

Super close to done!

RE: Help! New Engineer Need help identifying CV shaft spline standard

Learning the difference between involute spline and serration might be a good start.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
Spigor,

When I pop in your dxf file into solidworks or eDrawings (to compare to mine), the dimensions are way off. I'm getting a diameter of around 24 inches. Am I missing something here?

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
Nevermind sorry. It was a solidworks problem I believe. I imported it via mm instead inches and it came back to scale. Matches well with mine too. Thanks lfw618 for that modeling tip and Spigor for dxf ;)

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
spigor! It worked well. May I asked what program you use for involute modeling?

RE: Help! New Engineer Need help identifying CV shaft spline standard

2
I thought that if I used an off-the-shelf program I would not know how the things are done, so I wrote my own programs. Therefore, I'm able to adapt to unusual measurement data sets by writing some custom calculation procedures on the spot. This particular involute modeling piece is written in C++ add-on to MegaCAD.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
Cool! I'll look into that but utilize SolidWorks and Matlab/VBA. I've found some pre-written programs in VBA that works with SolidWorks but no luck with them yet. I'll keep digging. Thanks again

RE: Help! New Engineer Need help identifying CV shaft spline standard

I use excel , wrote my own for my particular needs, but I had to expand and use of other programs. as check and balance , all programs should agree,
surprisingly some don't. I wrote special settings and requirements for the gear cutting & grinding machines for my old companies, I since had to expand.
as automation(CNC) is now the norm. To understand the underlay computations are a valuable understanding how to manipulate the numbers.
look for simple errors in the gears, to catch it before it's in production. surprisingly there a lot of errors or over tighten requirements on engineering drawings.
or sometimes not tighten enough. to meet final requirements.

RE: Help! New Engineer Need help identifying CV shaft spline standard

mfgenggear
When you left your old companies, was there somebody to take over?

RE: Help! New Engineer Need help identifying CV shaft spline standard

@Spigor of course no one is irreplaceable. pass on the experience and knowledge..
but it takes many years,,

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
mfgenggear, totally agree. That is what my professors always said too bigsmile. I want to write my own because I'll need to anyways and it's a good thing to have on my tool belt. I'm going to soon start back up on my original project that got me started on this in the beginning; custom 4th gear for my car/ car's community. Would definitely appreciate everyone's insight on that as well. I've tried reaching out to gear engineers on linkedin/calling shops with no luck. It seems a lot of gear engineers are very hush hush with their knowledge, which is totally understandable.

I think i'll post my design sheet for helical and spur on a new thread. Currently with AGMA safety factors in place, none of my designs will work. When I tried calculating a optimized geometry factor, that never worked out as I got overwhelmed with all the math. I am sure the width constraint is the problem. So far I've decided against spur because the gear is in the middle of the shaft. I think I may just reverse engineer stock profile and slap carburized 9310 on the drawing. See where that gets me. Background on it: constant mesh 6 speed transmission, teeth shear on 4th gear at about 850 wheel rated hp, or 650 wheel rated ft/lbs. Will be making both drive gear and 4th gear. None of the other gears break at this power level. 1:1 ratio.. all load from engine on these two gears. 5th and 6th gear is not necessary to beef up, as in drag racing you stop at 4th.

But who knows what will happen to my gear project with this economy... I am in aerospace and it's being hit hard at the moment.. may have to push my gear project back.

RE: Help! New Engineer Need help identifying CV shaft spline standard

@speedracerfast thank you for the comment.
If may kindly suggest a commercial program lease for a year, MIT Calc is very reasonable.
a free program is Fairfield , search the post here in gearpulley forum.
I got involved with helicopter transmission 10K HP .
what is nice about these programs is one can change the geometry at an instance.
but it will allow you to verify the program you wrote that the results are close.
In-put the torque, or horse power, RPM, gear ratio required.
it will give the safety ratios that you require.
input the values of Material , and SN curves.
9310 steel has to be carburized and is a very expensive cost.
and generally requires post grinding the gear teeth.
maybe an alternative would be 4340M core about 40 HRc
then induction harden the gear teeth.
how precision do the gear teeth have to be?
AGMA Q 10-12?

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
@mfgenggear I will get back to you on that! I'm going to make a new post here soon. I have another 4 projects I've picked up (one part has two splines this time ohhh boy!) on since someone else has now starting offering a full dog box 4 speed transmission kit. Obviously it's expensive and I no one is sure about results. So my idea my come in handy. Obviously, the indiviual won't be able to shift as fast with syncro engagement but it will be much cheaper if I can get them CNC'ed.

@spigor I was looking at your plots again, may I ask what was your tooth thickness at pitch diameter and pitch diameter itself for that model? I am getting .0780" and 1.000" respectively. My own model is leaning more towards ANSI 92.1 class 6 standard with .778 and 1.000" respectively.

I am trying to confirm some things on my own because it's being sent off to manufacturing. I know your green model fit like a glove with EDM sample I got.

RE: Help! New Engineer Need help identifying CV shaft spline standard

I confirm circular space width (not tooth thickness), green plot .0780" at 1.000".
As far as I know, ANSI B92.1 24/48DP 45PA Class 6 has Max. circular space width .0775, so outside the tolerance and would indicate Class 7 with Max. circular space width .0791.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
@spigor right circular space width not thickness. Would it safe to say the green plot isn't following the standard at all then? Or could it really be class 7 and just worn out a bit, thus skewing the results? I am not sure what to do here and wish I noticed this earlier. I was hoping to put a standard on the drawing then manufacturing has something to go off of.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
I should also say the drawing has a table of:

Module
Number of Teeth
Pressure Angle
Circular Space Width
Major Dia
Minor Dia

Then under that it says: "Spline Standard in accordance to ANSI 92.1-1996 Table 57 Class 7.

I will obviously send them the DXF file for their reference, along with it in the 3D file on the actual part (igs or step).

I think that will be a enough? They agreed to cut this spline, but I originally told them class 5.

RE: Help! New Engineer Need help identifying CV shaft spline standard

What circular space width did you specify on the drawing, .0780? What about the tolerances?
Did you specify any tolerances for the major and minor diameters?
If you got this standard, you could see what data should be placed on the drawing and that a lot is missing (like tolerances and pin dimensions).
However, you could just specify what spline do you want and that should force the manufacturing to obtain all the data needed from the standard on their own.

You could just specify:
Internal involute spline
ANSI B92.1-1996 (the "B" is important)
Fillet root side fit
24T 24/48DP 45PA Class 7

If your part looks to be worn a bit and could be tighter, go for Class 6
If it could be a lot tighter, go for Class 5, which is the standard and the most probable.

The green plot sits inside the Class 7 tolerance field, as measured on the part. Again, check the part for tightness with the mating part.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
@spigor I never got to EDM the pink one you made or the class 5 according to B92.1-1996 I made. All I got to confirm was the green one you made fit well, how tight not sure because my business partner in a different state felt it out. I know I do not have all info in that table and sorry I should've been more clear on my issue.

.0780 class 6 (reference below). I thought class 6 was a good in between based on the .0780. However, I'm just worried because, again I am not even sure this green spline follows the standard anymore? The green spline had no fillets from what it looks like? Is it a Flat-root, major diameter fit? I'm probably complicating/overthinking this entire scenario because obviously there is a radius on the male root and it fit well, very little play/backlash.

Here is what I have:





I should note, our manufacturer will be doing design verification for us, but I'd like to hit it right first try and not waste money, hence why I'll just provide them the dxf file.

Again, thanks for the help and insight spigor.

RE: Help! New Engineer Need help identifying CV shaft spline standard

Hi Speedracerfast
I recommend to let the gear shop reverse eng this spline for you.
The cost required is very reasonable
For a peace of mind.
Except if you can go there with the part and enjoy the tour.

A bit about splines
Splines are verified with spline gages.
For external , max effective tooth thickness is verified spline ring gages.

The internal min effective size is verified
With spline plug go gage.
Max and min effective can not be verified with pins.

So the spline verification will be with
Mbw or mow for actual min and max tooth thickness for external spline.
Min and max tooth space for internal spline.
All classes have the same min and max effective size so it will all assemble.
The tighter classes have less back lash.
For tighter requirements.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
@mfgenggear right. But out of curiosity is my though process right? class 6 seemed good in between from what I know with backlash per business partner's provided insight/info... but what you're saying makes sense: there isn't a concrete way to know with the way I have gone about this.

We have some internal spline gauges at work (we need them for first article inspections).. doubt we have what I need. I hope there is someone local to me with the setup. Most likely in CA. hmm.

Can you elaborate on the acronyms mbw or mow? I can't decipher .. probably due to lack of sleep YIKES.

RE: Help! New Engineer Need help identifying CV shaft spline standard

Measurement between wires
Measurement over wires.
What general area are you in ca
Gear mfg is a small nitch
I can maybe recommend a shop.

RE: Help! New Engineer Need help identifying CV shaft spline standard

Also an example
An external spline can be shaped or Hobbed
And be over sized on the max actual tooth thickness mow, as long as it does not exceed the max effective size.
Yet it will accept the go gage.
That means that spline is almost perfect.
The gage will verify total index error,
Involute error, lead error, and size.
When making one or two parts, and no gages
Then it can be inspected to mow, and analytical inspection of the individuals spline tolerances. Mow, lead, involute
Total pitch error, an so on.
But with out gages there is an over tighten of tooth thickness size.
A gage gives more tolerances.

RE: Help! New Engineer Need help identifying CV shaft spline standard

Hands down the best way to reverse engineer a gear or spline is with an involute gear checker. If the correct diametral pitch and pressure angle is obtain it will have a straight involute.
And that spline or gear data is correct.
No guessing.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
@mfgenggear makes sense but I need to sleep on that info. I'm just confused on your last two sentences there:

"But with out gages there is an over tighten of tooth thickness size.
A gage gives more tolerances."

I am located in Seattle, not CA. I only was mentioning CA because I know my real job sends almost all gear measurement work out to CA. Know of anyone in Seattle or WA area? Google is showing nothing. Worst case I can ask procurement folks at work and see if they can help me out.

Hopefully I can get a quickish lead time as we've already collected $$ for group buy. Our margins are terrible (really really bad.. as expected with something like this) and really only proceeding with this to help out the Isuzu community.

I should also note, the only big company that would take this project was 3D Hubs, and all the of their competitors didn't want to touch a internal spline this small. Granted, I locked in 3D Hub's quote during COVID outbreak when it hit China, which is probably why this project is still active as they gave us a good price and wanted the work badly. Otherwise, the margins were actually negative unless sale price went up significantly. I am still pretty skeptical of the 3D Hub's spline capabilities, because the sales rep didn't know if it would be broached or EDM'ed. If it doesn't turn out I'll send them back. Plus they are going to do design verification with us (i.e send us two sets for us to check prior to maing the rest of the batch). Any thoughts on 3D Hubs? I'd love to get these made by a reputable shop, but with quantity low, the quotes were high! Most shops turned me away.

RE: Help! New Engineer Need help identifying CV shaft spline standard

Verifying with the mow instead of gages pinches the tolerance. With gages the max mow becomes a ref .

RE: Help! New Engineer Need help identifying CV shaft spline standard

@speedracerfast
A small # of parts it more reasonable to edm or shape
A broach has a long lead time, and can be very expensive.
But with a large number of parts it can be
Amortized into the cost.

Contact Forest City gear in Illinois.
Or broach Masters Inc in ca.
Or look for gear shops that advertise
Reverse engineering there are a few.
But my mind is blank do to a darn headache 😣

RE: Help! New Engineer Need help identifying CV shaft spline standard

The reason I have written "fillet root" in the specs is because there appears to be no flat root version for that 45° spline in the ANSI B92.1-1996. Long story short- on an internal spline that "fillet root" has more to do with the major dia. than with the real shape of the root itself. The shape depends more on the technology it has been made with. A broach will in most cases make almost no rounding. A standard shaper cutter will make a small trochoid shaped rounding, when a bigger fillet is needed it must be calculated and modified (which by the way is not an easy task and I'm very proud of being able to control the fillet or chamfer making in gear and spline shaping). WEDM will inevitably make a rounding.
A flat root spline would also work with your mating part, which has been proven because the green plot from me fits.
If you want you can leave the "fillet root" out of the description, since no other 45° version seems to exist in the standard.

If that's good you have got everything ready and proven with numerous measurements and checking with the mating part made to the green plot, except for the class (assuming it is ANSI B92.1, but that looks like a pretty safe assumption to me). Maybe you could put both mating parts together, place a dial indicator tangentially on a given radius and check how much rotational backlash you have on that radius? Not going into too much detail with the effective and actual dimensions, you could see how much space width difference there is between Class 5, 6 and 7 on the pitch diameter of 1", scale your measuring diameter to 1" and see how many .001s would you like to take away, hence finding out what class do you need.

@mfgenggear: a headache again?

RE: Help! New Engineer Need help identifying CV shaft spline standard

@mfgenggear makes sense but I need to sleep on that info. I'm just confused on your last two sentences there:

"But with out gages there is an over tighten of tooth thickness size.
A gage gives more tolerances."

@speedracerfast

all the above are in the ANSI B92.1 obtain a copy and under stand it completely.
study the sections on spline gage design.
I have been designing spline gages for many years I had to under stand it very well.

@spigor
@mfgenggear: a headache again?

yes my eyes are getting tired, to much starring the computer LCD screens
even thou I have eye glasses, I have a problem with glare, always have for years.

RE: Help! New Engineer Need help identifying CV shaft spline standard

"If that's good you have got everything ready and proven with numerous measurements and checking with the mating part made to the green plot, except for the class (assuming it is ANSI B92.1, but that looks like a pretty safe assumption to me). Maybe you could put both mating parts together, place a dial indicator tangentially on a given radius and check how much rotational backlash you have on that radius? Not going into too much detail with the effective and actual dimensions, you could see how much space width difference there is between Class 5, 6 and 7 on the pitch diameter of 1", scale your measuring diameter to 1" and see how many .001s would you like to take away, hence finding out what class do you need."

actually that is a good plan, to make sure parts assemble use the existing parts to verify no interference when assembled.
and make sure they fit. measure twice cut once.
Just remember a class 5 spline can be cut to look like a class 4 or 7, because the max effective size on an external spline will accept the go gage.
I would say a class 5 spline would be safe. tighter class would be to give better back lash control.
but causes issues during heat treat, do to distortion.

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
"but causes issues during heat treat, do to distortion."

With that said, does anyone how what affects EDM will have on spline strength or distortion with 4340 alloy? I can't find concrete essays about the localized effects from cutting with this method. I am doing no post processing. This their general material page for 4340: https://www.3dhubs.com/cnc-machining/metal/alloy-s...

I misspoke earlier, 3-D hubs rep was persistent on power skiving to cut this spline. I told him that's not possible on an internal this small, that's when he back tracked to EDM. I understand broaching is for mass production, but I was thinking you can rent the tool if it's a standard spline or something. Not sure!



RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
@mfgenggear for your headaches, maybe wearing Blue-Light-Filtering Lenses would help you out? I personally run blue light filter (close to max dim) 24/7 on all my computers. On windows it is located on the bottom right windows center... right click to alter how much it dims. College killed my eyes since everything I did mostly was through computer screen.

RE: Help! New Engineer Need help identifying CV shaft spline standard

17 Jun 20 20:22
"but causes issues during heat treat, do to distortion."

With that said, does anyone how what affects EDM will have on spline strength or distortion with 4340 alloy? I can't find concrete essays about the localized effects from cutting with this method. I am doing no post processing. This their general material page for 4340: https://www.3dhubs.com/cnc-machining/metal/alloy-s...

I misspoke earlier, 3-D hubs rep was persistent on power skiving to cut this spline. I told him that's not possible on an internal this small, that's when he back tracked to EDM. I understand broaching is for mass production, but I was thinking you can rent the tool if it's a standard spline or something. Not sure!

The company's to verify with if they have a broach in stock would be ASH gear rent or buy and (Broach Masters Inc.)BMI rent but the would have to do the broaching.
send them a copy of the sketch.

3dhubs has no gear inspection equipment, I would not recommend them for that reason, they are not a gear shop.

If the parts are broached it would have to have a interim heat treat Normalize, Harden and temper to 30-36 HRc, then final heat treat after broach , unless a company has hard broaching capability.
same for shaping with a small shank type shaper cutter. again check with ash gear , google them.
with wire cut ask for .0005 max recast layer, on heat treated parts .001 max decarb is normally permitted, hydrogen embrittlement relief after wire cut.
if fully heat treated with a hole to pass the wire thru, It would have to be wire cut with .006 wire to produce .010 max fillet root, and it's very slow going also expensive.


RE: Help! New Engineer Need help identifying CV shaft spline standard

@mfgenggear for your headaches, maybe wearing Blue-Light-Filtering Lenses would help you out? I personally run blue light filter (close to max dim) 24/7 on all my computers. On windows it is located on the bottom right windows center... right click to alter how much it dims. College killed my eyes since everything I did mostly was through computer screen.

@speedracerfast
I changed the PDF & Excel sheets to a light blue screen
see if that helps

RE: Help! New Engineer Need help identifying CV shaft spline standard

(OP)
@mfgenggear nice that should help. Also sitting in a dark room looking at a screen doesn't help too haha.

Overall update is my BD partner wants to proceed with 3D Hubs despite my warnings about the spline cut. I'm waiting on responses from ASH and Broach Masters. Waiting to hear back. 3D Hubs reviewing my finalized drawings, so if quote goes up I'll be looking somewhere else.

Furthermore, when my BD partner and I were talking, he reminded me of the aftermarket cv shafts that people run. They're really sloppy and have tons of backlash. He told me about half the cars left are using these CV shafts with no issues. This car probably makes no more than 250 wheel torque, plus remember the fact these are the rear hub/spindle assemblies with a electromagnetic clutch sending power to back;' it's not seeing feeling much torque.

I guess I've done my job *shrug* and given the warnings. I'll continue to work on other options though in case stuff goes wrong. Thank you all for the help and advice. I've learned and ton and keep learning. I'll post up about the gear soon.

RE: Help! New Engineer Need help identifying CV shaft spline standard

@speedracerfast
Thank you from all of us
For the kind words and the update.
Best
Lee

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