I feel your pain. I did the same thing to the oil pan. The alum works but you need to keep it hot.My Little Demon block (partially finished) is having a soak in an Alum solution to dissolve out a broken tap and broken drill bit. The tap I blame myself, the drill bit I blame the mill.
I bought a cheap electric burner off Amazon and ceramic Corningware pan from eBay. For some reason, the spouse didn't want me using her Corningware or the stove top.I’ve been putting it in the microwave every now and then to keep it hot. The first time I did this I put the measuring cup on the stove burner. CRACK! Then I read that it is not for stovetop use. My wife was not amused. I can see the tiny stream of bubbles coming from the steel parts, so it is working.
Hi John from down under! One of the ways I use is to rough out all the journals a bit at a time this seems to spread the turning load proportionately as you go. In your case I would suggest using a fixed steady to support the shaft to turn the end main journals and i would shorten the length of the shaft to just over finished length this will reduce the flexing at the weak points where you have finished the journals. Looking at the photo you maybe could have chucked the shaft and turned the main journal at the head stock end and put no load on the weaker areas. Hope this helpsNovice question. I'm having no luck with the crankshaft. Bent another trial crank, this time with 12L14 instead of aluminum. I got through the four rod journals and was working on the farthest end from the spindle when it grabbed, spit out two "cookies" and bent the crank. I get lots of chatter and then the tool grabs. I have the tool as close to on center as I can get it and have it honed quite sharp. Using HSS at 180 rpm. Stock is 1" round.
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The process I tried is to do all the offset turning first, the four rod journals. I mill away the excess of the furthest journal away from the spindle and turn it to size. I then mill away the second rod journal and stick a "cookie" in the first and turn. Rinse and repeat for the third and fourth. I then started to turn the crank end furthest from the spindle to size. That was where it grabbed and bent the crank.
Should I do the work sequentially from the end away from the spindle instead so that the crank is stiffer from the driven end?
I previously tried a sleeve like that when I was using aluminum bar for tests. I used spiral thread hose clamps and it was not strong enough. I don't have a welder but I might be able to braze the cylinders on the end.The raw crankshaft is supported everywhere but at the journal or throw this is being machined.
My tool bit is essentially that design without the center relief and wider. I will reduce the width and relieve the center. I can't believe how clean the grinde is on your tool. Was it done on a tool and cutter grinder or by hand?The tool bit looks like this and is just slightly narrower than the width of the bearing surfaces so it can cut from cheek-to-cheek.