hi andy, thanks for getting back to me , the measurments are as follows at the largest point of the conical spline is 22mm and were it tapers down is 18mm and the whole length of the spline is 22mm hope this helps, if its what iam looking for can you let me know how much you want for it and postage costs, also iam not sure how id pay you for it ie cheuqe or card or paypal, perhaps youd let me know, many thanks regards john