as the title, does anybody have a CAD drawing they can email to me in DXF form of the end profile of the ford sierra diff stub shaft splines.

I need to create a toolpath for a CNC spark eroder.....I have a cunning plan for my driveshaft dilemmas!

anybody?

Or anybody know a potential source? I can think of several but I doubt they would part with them as they make transmissions!!!

[Edited on 9/11/06 by NS Dev]

the profile is standard so if youve got the major/minor diameters and the spline count it shouldnt be too hard to draw it up

Can get the dia's and count, but not sure what you mean by standard profile?

shouldn't be had to cad up, considered cobbling somthing up in the lathe to cut them before but wasn't sure about the heat treatment.

all you need is no. splines, major diam and the included angle of the spline peak, 2 min job to draw up

EDIT
you dont need the spline angle

[Edited on 9/11/06 by liam.mccaffrey]

I know its easy to draw up, but on such a small spline how do you measure the included angle?

Best I can think of is 10:1 shadowgraph and a protractor and hope Ford chose a round number!

[Edited on 9/11/06 by NS Dev]

quote:

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Originally posted by NS Dev
Can get the dia's and count, but not sure what you mean by standard profile?

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ahhhh!!!

wasn't aware of that, the splines look straight sided to my eye, but maybe not then!

will get it drawn like that and shadowgraph the drawing against the diff side-gear and see if they match!

Right, had a good look at the splines last night and I am sure they are straight sided!

if I get the major and minor diameters and spline count, can someone on here draw it for me and email me the DXF?

I can check it then on the shadowgraph cos I am not convinced!! I'm also less than sure of how to draw it, there seems to be a lot of discussion on eng-tips.com about this subject!

Didn't the man who used to do MK's one off bits use a milling machine to make them? I think Jon said he did them some for the GT1 but that may have been different. Are they heat treated or just made from high grade material?

[Edited on 10/11/06 by Peteff]

material wise, depends on what you want to do with them.

I can sort that anyway.

For this sort of thing a lump of EN16T, the engineers best friend, normally does the trick, although I "should" have a fairly abundant supply of EN24 (817M40) in the near future so a lot of tough bits may be made from that! Its over 800N/sqmm tensile as ssupplied, and a LOT more if heat treated.

I can also access heat treatment facilities for free too, but I am struggling on the drawing!

I am alomst sure that the splines are not involute there is no need to be, gear teeth however almost always are involute profile.

there is no need for the splines to be involute, involute teeth are to smooth and decrease parasitic loss of rolling meshed gears

But how do I draw the splines? They don't come to a point at top or bottom, so i need the included angle to be able to draw them, unless somebody has a clever idea!

I've been watching this one with much interest and now I'like to contribute this-

If you know the external dia and the base dia and IF you can/could also measure the top/and bottom width of a peak and a trough then in theory there would be a mathematical (or autocad process ) of creating the included angles.
I'm thinking about a polar array that is rotated as it's generated.
Also toying with the idea of placing bluetack or similar a pressing into the shaft to give a profile. Grease the shaft and press the blue tack on to it. Place the whole lot in the freezer and when done slide the blue tack off. Then shine a light through it to create ashadow on a bit of white paper (move to magnify perhaps) and measure the angle from this.
Now these are only wild thoughts but it maybe just the answer to what you need.

What do you think of my ideas.

I will be taking a sliver of a shaft using an abrasive cutoff, then putting it on a shadowgraph machine at work (which backlights it and magnifies it 10:1 at the same time.

This is fine but still hard to be really accurate, and splines need to be just that!

Yes, dead easy to rotate an array in autoCad, just tell it the pcd and how many and it does it for you, but it is drawing what to rotate really accurately that I am stuck on.

When I get the spare diff it will come apart and be dissected!!!

PS what I really need is what GB Eng use, a really accurate 5 axis CMM, great for reverse engineering!!