Slightly frustrating day, I wanted to thread up some 10mm titanium bar to replace the two long engine bolts. Some while ago I bought (on advice from Nasher I think) a tail-stock die holder. This was my first opportunity to use it. I comes with 2 sizes of die holder both too big for the 10mm die that I have which is 25mm diameter.
I thought about turning up some aluminium bar but remembering the struggle I had before with running the die down some 8 mm titanium bar I quickly rejected that idea. So I spent a long time scouting round for a bit of steel 38mm diameter to fit in one of the supplied die holders. I had the martensitic steel bar but could not face machining that.
I did find a steel collar bored 25mm and 40mm outside diameter but it was only 16mm long and I need at least 13mm so I had to work out how to hold it in the lathe.
In the end I drilled and tapped the collar and with a 6mm grub screw attached it to about 75mm of 25mm diameter aluminium bar which went nicely in the 3 jaw chuck.
The threading went OK after I machined a 5mm lead in on the 10mm bar but it was hard work requiring two x 18 levers, one to lock the lathe 3 jaw chuck and another on the die holder.
Result though is two engine bolts in titanium saving 125g on the steel items. I also got left with a 50mm length of 10mm titanium which I will thread to make the crankcase rear brake hanger reaction rod fastening.
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