34 spline axles - what's the full specification?

[MonsterMaxx]

I've been tasked with designing a shaft that fits the 2015+ mustang S550 differential.

I understand that this is a 34 spline axle, but that only limits the selection so far.

A scan of one that I'm using doesn't seem to be right to me, looks like a serration spline which is good for centering, but not for carrying torque.

Does anyone know the actual specification for which type of spline it is?

Thanks so much to anyone who can answer this for me.

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[308 Cal. Bullitt]

For a very long time now, all typical OEM splines were a 30° pressure angle. Involuted.

Summers Brothers, in the 1970s, built the 1st 40 spline spool, & axle sets. These were no the typical 30° angle, but instead, they were 45° pressure angle, with a 1.750" outside diameter axle shaft.

This 40 spline design was done to replace/upgrade, the previously largest avail diam., which were the 35 spline axle shaft size, modeled after the Dana 60 oem rearend axle. It too (Dana 60) was a 30° pressure angle, & was a 1.500" outside diameter.

I was not aware that the newer Ford Super 8.8" as being a 34 spline. What is the outside diameter of this spline count? The previous 8.8" was a 31 spline, 30°, if I recall correctly. It used a 3.062 carrier bearing diameter, which limits a person safely to 33 splines, & makes fir a really really thin journal at 35 splines. Yet still, sone manufacturers made 35 spline spools for 12 bolt GMs, & Ford 8.8" rears. I was never a fan of it but on a limited use drag car, it was better than a 40 spline axle in a spool that used the 3.250" diameter carrier bearing. Most of us preferred the 3.812" carrier bearing journal sized cases, to plug the 40 spline into.

You can put a 30° pressure angle axle from someone like Strange Engineering, ibto a Mark Williams 40° angle spool. You can't go the other way. It holds up well enough that even the manufacturers don't care enough to force you to buy the correct mating part.

Good luck... no idea if this helped.

 

[Cory S]

If you come with something as stout as the current aftermarket axle offerings for 30-50% of the cost, count me in.

 

[308 Cal. Bullitt]

Btw,
Are you planning to cut splines I assume?
Or hobb your axle splines?

& whats your plan for heat treatment?

Factory splines for decades were rolled, & induction hardened vs the more current stuff in aftermarket are cut, & then the entire axle is heat treated.

Vs induction hardened, that just does the splined area. All aftermarket quality stuff is fully heat treated.

 

[308 Cal. Bullitt]

If you come with something as stout as the current aftermarket axle offerings for 30-50% of the cost, count me in.

I have had hundreds of custom axkes built, & the only way to get where you want to be us cheaper material like 1541H, or going to South East Asia for mass manufacturing. Nobody can build small runs for a 1/3 to half less than Mike Long (G force) or others.

If you can get axles built that cheap, they aren't gonna be in business long enough to stand behind it.

Just throwing facts out. No disrespect. Hope you can pull that pricing off.
We couldn't. Unless it was offshore. & they eventually sell your proprietary product to anyone that wants it by the 3rd yr of SEMA, but up the road at the general rebuilders show the same week as SEMA.

Not possible, without going to China, & having to put an engineer or a oversight person in the forging area, full time, to watch the metallurgy. They will cut corners on the raw materials you specify, as soon as you stop watching.

 

[Cory S]

I have had hundreds of custom axkes built, & the only way to get where you want to be us cheaper material like 1541H, or going to South East Asia for mass manufacturing. Nobody can build small runs for a 1/3 to half less than Mike Long (G force) or others.

If you can get axles built that cheap, they aren't gonna be in business long enough to stand behind it.

Just throwing facts out. No disrespect. Hope you can pull that pricing off.
We couldn't. Unless it was offshore. & they eventually sell your proprietary product to anyone that wants it by the 3rd yr of SEMA, but up the road at the general rebuilders show the same week as SEMA.

Not possible, without going to China, & having to put an engineer or a oversight person in the forging area, full time, to watch the metallurgy. They will cut corners on the raw materials you specify, as soon as you stop watching.

I was pretty much reaching for the stars on that. I have axles I’ll never break already. .

 

[MonsterMaxx]

Can't really say what it's for, but can say this is a custom racing application where a ford rear end from a s550+ 2015 mustang is being transplanted into something else.

I'm just here to do the engineering.

The stub shaft I have to reverse engineer has no markings so my theory is that it's aftermarket to begin with. And maybe the splines aren't the right ones.

I would think an involute spline would be a much better choice than a serration spline. And in fact is what appears to be used on the Outer Axle/CV.

Freely admit I'm no expert on splines, not my FIRST rodeo, but...

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