The thread diameter (OD) is 5.05mm and the pitch is about .81mm (15threads=12.2mm) length is around 28mm I don't think it's a metric thread but you might be should be able to work out the size from that.
edit Just saw Mic's post and 20 TPI they aint. from my calcs they are somewhere around 30 to 31 TPI and 1/5 inch in diameter
