MT2/B12 Drill Chuck Arbor

I have a new Rhom drill ckuck with a B12 taper that I would like to use with a draw bar in my mill (MT2 taper spindle). I have tried all
the usual suspects (including Chronos, ArcEuro, Chester, RDG) but no one seems to stock such an animal. ArcEuro list one in their catalogue, but have just discontinued it. Plenty of tanged arbors, but I want one with a threaded end.
Before anyone suggests it, tried to make one by cutting the tang off an arbor from RDG, then drilling and tapping it, but the arbor is hardened so I didn't make a lot of progess. In desperation I annealed the end of the arbor, which allowed me to machine it, but the arbor distorted in the heating, so back to square one.
Before I start machining a B12 taper on a blank end MT2 arbor, can anyone suggest a supplier who might be able to help?
TIA Mike
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