A quick question for any kind person who has the answer – the auto quill feed button/knob that is at the centre of the manual quill feed hand wheel, whereby you push it all the way in for down feed and pull it all the way out for upfeed – what is the thread for that button please? I have lost the end button and want to just insert a bolt into the small threaded shaft to push and pull but cannot measure it as it is too small….