Similar recent thread may hold the answer

Dowel pin.

This may well be the source of your problems. The original Myford 4 way toolpost handle was about 4" long or maybe a bit more and I find that by giving that a good tightening by hand, my toolpost never slips.

It might pay you to make sure the bottom of your toolpost block and the topslide surface it sits on are both perfectly flat. Also it seems some of those cheaper QC toolposts have a hole up the middle that is a tight fit on the stud but is not perfectly square to the bottom surface. Application of a thin smear of engineer's bearing blue should give a consistent reading all round the two mating flat surfaces.

Edited By Hopper on 02/03/2021 08:24:49

The 200ml drip feeder was cheap on ebay but I had to true up the needle point before it would completely cut off the supply. After that, I found the flow easily controllable by observing the drip rate through the little window. I tried cheap Chinese coolant hose but it leaked at the joints so I replaced it with good-quality Loc-line hose made in the USA. The hose holds quite a bit of the oil in its joints so the response to the drip rate can be delayed which is a slight nuisance. At some point, I might replace it by plain clear aquarium hose with a bendy wire down the middle. Apart from those hiccups, I’m well pleased. I can position the drip feeder anywhere within a 100mm radius circle, swing it in towards the tool or out of the way when not needed.