Myford ML10 Lathe - Lil Brother Hit Miss Engine - Crankshaft Final Cut

Here I’m taking the last cut on the crankshaft leaving 1.5 thou for polishing with wet dry sandpaper. Note the small bolt between the webs to prevent collapsing while machining. Only light pressure on the bolt just enough to close the gap. CA glue holding in place works fine.

[@ianrenshaw6653]

Please Like and add Comments. Thank You!

[@RustyInventions-wz6ir]

Great work mister. I still have to somehow make a crank shaft for the engine I am working on. I’m scared to even think of it. He he.

[@ianrenshaw6653]

This was the first time I made one from scratch. In the past the kits I worked on had a forged crankshaft that just required some finishing work. For this one I used a 1/2” cold rolled mild steel bar. The finished size was 5/16” so lots of extra material to work with. I rough cut the bar to size so the main shaft was 1/2” square. The legs did bow out a bit when cut as the internal stress of the bar was released. I then used a torch to bring it to red heat and let it air cool. I left the legs bent and made roughing cuts to bring it close to size. Nothing seemed to warp and I was able to bring it to final size with no further issues. I may try hot rolled mild steel bar next time but find that stuff to be very gummy and hard to get a good finish. Anyway hope some of this is useful. Good luck with your crankshaft and hope you can see that you don’t have to run your lathe at high speed to get good results. Sometimes slow and steady really does win the race. Cheers Ian