DIY lightweight crank
#21
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Buy a rotary table for you mill, its worth it. You'll get the bore in the bearing cap close enough that way, the line bore from the machine shop will get it perfect. 4140 PHT definitely wants carbide endmills, but they're pretty cheap, and it cuts like budda with them. I have all my short use tooling and gauges made from it in the tool room at work, they blow through it quick and its hard enough to last like a week in production.
Here is the crank with the milling stage complete. Took off a total of 4lbs off the crank.
![](https://www.miataturbo.net/attachments/engine-performance-56/168103-diy-lightweight-crank-80-20160412_215848_zpsvo4onhzf_0aea12b5e3d995fa0ba3cb19950d447b834258e9.jpg?dateline=1460470629)
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Ruined_miata
General Miata Chat
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03-13-2016 09:33 AM