Round to oval paddle shaft mandrel.

Hi all, new here and don’t know much about grinding at all, hence a plea to the experts.

I manufacture carbon fibre kayak paddles amongst other things.

I need to make a metal mandrel to make kayak paddle shafts out of carbon fibre, unfortunately a bit more complex than the standard oval shaft.

The mandrel needs to be 26mm round at one end for about 250mm and then going to an oval of 25mm by 27mm.All with a very very slight taper to assist removal of the finished product.

How would one go about grinding such a mandrel?

Thanking you all in advance.

From your description I am visualising that you want to make a mould tapering from a round section to an oval one on which carbon fibre material like a clingwrap film is wound around the mould.

Without knowing if this is technically possible and that my guess is remotely correct then I can also visualise a cylindrical grinder entering the equation. But how a grinding wheel can be given the movements to produce a tapering oval shape is beyond my understanding.

I just thought about the alloy frame on my, unused by me, mountain bike. It isn't tapered but it is oval shaped. How was that achieved? Did it start out round and then get modified?

Any carbon fibre wrapping around a mould that is 26mm diameter and transitioning to an oval that is 25mm by 27 mm major diameter would not allow the part to be removed. Is there something missing in your explanation?

Point taken, it would have to be 26 by 27mm. But I just measured a shaft and its 25mm by 27 which makes one wonder how are they doing it, starting to suspect that they use a 26mm round shaft and after its cured reheat it and squeeze it oval, as you point out it would not release otherwise. The other option is to mould it in a split mould using a inflatable mandrel. At times we tend to look for complex solutions to simple problems, thanks for the responce.

High speed mill (Sodick) between centers.Amazing machine.Forget grinding.