I should clarify the axels I saw brake were a terrible l design from the start they were 1.5 OD .125 wall with steel inserts bonded in the end and one .25 roll pin going trough it. The bond of the glue broke and the pins tore out of the holes as soon as power was applied.

Our drive train had four shafts two Taylor axles and two made shafts built from 4340. Next year I will build everything from 300m that’s what the Taylor axels are built from.

quote:

Originally posted by RiNaZ:
tom, do you machined your bulkhead or casting?

Machined on a 3 axis CNC mill.

guys i had a query related to manufacturing of hollow driveshafts,if the outer dia of splines is less than minor dia of hollow shaft or dia of splines is in between major and minor dia of hollow shafts then you would weld the splines to a hollow pipe or what is the other alternative??

ankit dhingra
www.defianzracing.in
delhi college of engineering

If i understand what you are saying here, it sounds like you are trying to weld a spline section with OD less than the OD of the shaft? If this is the case there is a good chance the driveshaft will break (depending on the diameter, if it is large enough than maybe not) and it will brake right at the weld. The weld fillet will create a huge stress riser right at the heat affected zone.

The weakest point is going to be the smallest part of the shaft and the stress riser is not going to help. you might as well weld the spline to a tube that has the same or smaller OD than the minor diameter of the splines.

Welding driveshafts isnt exactly the best engineering practice.

Welding shafts is like having a chassis welded with chewing gum instead of filler steel rods.

Your driveshaft OD needs to be slightly less than the cv joint spline root diameter. And the transition between shaft and spline must bee smooth without indentations from spline machining!!.. or your shaft will fail due to high shear stress concentrations on the spline root (remember that shafts also have shear stress directed axially on all the radial planes)

Also you need to design (or ask/find) a proper heat treatement/surface finish. Normally you'll need a softer core and a harder surface. You can achieve that with a proper quenching & tempering. To improve fatigue life and prevent crack propagation, a shoot peen will do the job.

Never make half holes (those that don't pass through the whole shaft) that induces insanely high stress concentrations and get weird with the heat treatment.

so guys if the outer diameter of splines is more than the major diameter of the hollow shaft,then it has to be in one piece(results in no welding),another query is that for that hollow shaft do i have to bore a solid shaft or do i start with a pipe.(because straight boring is very difficult to attain in india).
another query is that if i have a hollow shaft how do i incorporate the plunging system .

There is no point in making the OD of the shaft bigger than the OD of the major (or even minor) diameter of the splines. It will break at the smallest diameter. Additionally, the difference in diameter will cause a stress riser which will cause it to fail in that area.

On top of the stress riser, the heat affected zone will be weaker than the body of the shaft. It is generally not good practice to weld driveshafts, but if you do, making the diameters different on either side of the weld will only make things worse.

quote:

(or even minor) diameter of the splines. It will break at the smallest diameter.

That isn´t true at all, If you machine the splines (that´s not the better way to do so, but if you can´t make them via plastic deformation... you end machining them) the spline mill can left some little indentations on the smooth part of the shaft, because of that you´ll need to machine it slightly to a lesser diameter. See the Taylor race shafts. the shaft OD is less than the spline root.. that´s to avoid stress concentrations on spline transition to shaft

Yes i appologize, the spline will also cause a stress riser. I was referring to a shaft with changing diameter, the smaller diameter will be significatly weaker. When you have a spline it is something else to consider.