From TO4M - 1" x 8tpi to T38 - M33 x 3.5mm 8)
If it's Axminster 900 with SK100 to new Axminster with M33 thread (and either an exert or new chuck required).
I apologise (in advance) for wanting to spend your money Tim, but... if you sell the SK100 and advertise it on the forum and get back...