Fine and coarse spline axles
#1 _pallbag_
Posted 01 August 2007 - 07:33 PM
And what/how do you differentiate(hehehehe get it, DIFFerentiate) between both? 31 spline for eg. is a .... spline axle
#2
Posted 01 August 2007 - 08:06 PM
A.The diff is the bit between the axles regardless of coarse or fine splines.
#3 _pallbag_
Posted 01 August 2007 - 08:10 PM
#4
Posted 01 August 2007 - 08:40 PM
Fine has more but I can't remember how many ... haen't broken any in awhile (28 maybe ?)
So thats the easy method..... course or fine
The more splines the stronger the axle
Talking Ford 9" they start at 28 and you can buy axles and centres in 31,33,35 and beyond
#5 _Rob 5000_
Posted 01 August 2007 - 09:41 PM
#6
Posted 01 August 2007 - 09:42 PM
Coarse spline: I've broken plenty of these, they snap like celery sticks.What are the advantages/disadvantages of either a coarse or fine spline axles in diffs?
Fine spline: I haven't broken any... yet.
#7
Posted 01 August 2007 - 10:20 PM
Anyway the fine spline axles distribute the torque more evenly around the axle to compensate for its tiny diameter. I've been led to believe that they make a significant difference in strength.
#8 _73LJWhiteSL_
Posted 01 August 2007 - 11:46 PM
But then i though course was 11.
Shows how much i know.
Steve
#9
Posted 02 August 2007 - 12:35 AM
Coarse are cut further into the axle thus making the machined diameter of the axle smaller therefore weaker.
Edited by rodomo, 02 August 2007 - 12:36 AM.
#10 _HatchmanSS76_
Posted 02 August 2007 - 03:33 AM
#11 _82911_
Posted 02 August 2007 - 08:24 AM
fine=23 splines
early BW=25splines
lateBW=28 splines
passenger9"=28splines
commercial/racing 9"=31 splines
aftermarket 9" axles avaliable in 33/35/40 splines.
Small Dana's=25 splines
Large Danas =33 splines
I think that should clear it up sufficiently!
Cheers Greg..
#12 _73LJWhiteSL_
Posted 02 August 2007 - 10:27 AM
With all that info can I ask a mod to Sticky this thread please?
Thanks
Steve
#13
Posted 02 August 2007 - 01:20 PM
#14 _HatchmanSS76_
Posted 02 August 2007 - 09:14 PM
#15 _82911_
Posted 03 August 2007 - 07:25 AM
#16
Posted 03 August 2007 - 07:45 AM
#17 _pallbag_
Posted 03 August 2007 - 07:46 PM
#18 _uglybob_
Posted 03 August 2007 - 08:40 PM
#19
Posted 05 August 2008 - 01:05 PM
Please note that the die/mould for torana axles changed with the UC, so UC axles should be a much solider unit compared to an identically splined LH/X unit.
Grant..
#20 _202LX_
Posted 13 August 2008 - 03:13 PM
#21
Posted 13 August 2008 - 05:23 PM
#22
Posted 22 August 2008 - 12:59 PM
Almost - the later model (e.g. HZ) six cylinders had the fine spline Banjo centre (utes had LSDs too), which will fit into any Banjo housing. Then add UC axles which have the fine spline and you are away. You can also just rob the fine spline side gears from the UC Salisbury and put them in the Banjo centre.I have heard that you can use a kingy fine spline diff centre (HQ for instance) and UC axles in an LX/LH diff housing and get a stronger diff. Any one done this or know if it will work?
#23 _HQ SS_
Posted 23 August 2008 - 10:09 AM
differences between course and fine spline banjo axles and spider gears in pictures.
Also the differences between banjo to salisbury to 10 bolt axles and a few other diff related pictures
I have a few pictures here
http://gallery.oldho..._SS/Tech/Diffs/
that show the differences and general layout of various components.
Cheers Paul.
#24 _studricho_
Posted 02 June 2010 - 11:08 PM
When they cut splines into axles they are actually taking away material making the axle weaker. This was what my boss explained to me after I started to snap fine spline axles 28 teeth after getting rear axles made to suit the commodore stud pattern After snapping 4 axles I was told I needed a 9 inch and that's when the head ache began.
Was I miss-informed as a young apprentice?
#25
Posted 02 June 2010 - 11:52 PM
Some standard ones may be cold formed (particularly the V-type splines found on fine spline Torana diffs as opposed to the squaretooth splines found on coarse spline Torana diffs), I've only ever seen them machined but I haven't worked in a factory that mass-produces them.
One of the problems with the typical production car splined arrangement is that the outer diameter of the splined area is the same as the shaft diameter. This means that you get effectively a smaller diameter axle under where the splines are situated. So you're using excessive material for the same torsional rigidity if that makes sense. Basically you end up with a spline diameter that is undersized and a shaft diameter that is nominally oversized (or both undersized in the case of a Torana LOL) and isn't giving you any strength anyway because that isn't the weakest point
The best way to do a splined shaft is to have a larger diameter at either end of the shaft, with a radius leading into that diameter so that there are no stress concentrations (another problem with the typical production car spline arrangement). If the smaller diameter matches the depth of the splines, then you just machine the splines into that larger diameter, back and forth with an indexing head of some description, until you reach the nominal shaft diameter. This also means that the axle is allowed to 'wind up' a little bit so that the peak destructive forces are spread out over a matter of a very small timeframe which seems to make a difference, and when you have a shaft of this design it ends up being lighter too, which in a diff is bloody important if you actually want to go around corners and get the car to handle as well as possible.
Edited by Heath, 02 June 2010 - 11:57 PM.
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