Billet & Forged Crankshafts

[ronniejoe]

I agree - you'll never see a billet down-pipe on my truck, or billet brake hose, or billet fuel-level float - even tho they are cheaper than the forged versions.

Have been considerin' one o' them billet radar detectors, tho, and a forged Rolex ain't too bad, fer the price.

So, you're shown to be blowing smoke and you start mocking... I tried to be gentle.

The ease of making design changes in the billet piece is another strength over forged.

This is it's only advantage...not "another" one...as I already stated in my earlier post.

I've attached an image of a section of a crankshaft forging for your viewing enjoyment. Notice how the grain follows the contour of the shape. This is what makes a forging stronger than a "billet" piece or a cast piece. This is called "preferential grain flow".

Even if you cold work the piece of billet stock or even if you forge the billet stock into it's bar shape, the machining operations to get the shape of the crank will cut through the grain so that the grain pattern is interrupted. This yields a loss of strength in the finished part.

Bottom line: Make two identically shaped parts (in this case crankshafts), one from a forging and the other from "billet". The forged one will be stronger every time. End of story.