If you want to make useful things for hot rods there are many more items other than a part that is highly stressed and so open to failure.
You could specialize in certain brackets, and other such easier to make useful items.
To make a connecting rod ie. one that will actually work. You will need much more that a chunk of 4340 or what ever. To start with if the material has inclusions in it you will be sunk in the begining. Also you will need to have grain structure id'ed. And like the one fellow said. The best and strongest is a forging. You will never make a product productivly to sell on a manual machine. I ran them years ago. And mind you all you have to do is one goof up and many hours of work and the material go into a scrap bin. Not saying it can't be done. It would be a chore on an old K&T Rotary head mill which I spent some time on in the old days.
These days a person doesn't even need to be a machinist, a computer will do it for ya. But you do need to know a bit about how to go about it.
As far as making such things as a connecting rod for racing or ? If you don't have a grasp on engineering principles and the properties of the various materials, and the dynamics involved, and all the correct test instrumentation. You would be better off making a tool or something else useful. Because a pretty con rod can be just that and nothing more.
Sorry to sound so negative, but it just isn't practical with a limited amount of machinery.  |