Get a dozen or so standard nuts put them on a threaded bar or bolt , put it in the chuck & turn the first nut down to just over half thickness , don't put too much of a chamfer on the face edges/ flats as too much will see the nut slip inside the spanner . You only need to tale the f a smidgeon off the sharp cut edge not a full nut sized chamfer . I used a swiss needle file to kiss each flat on the nut before I used a spanner to take the nut off the rod whilst it was still in the chuck .
I only gave mine a kiss of chamfer and also ground the back of a ring spanner to remove the counter sink effect so there was as much metal to metal contact between nuts & spanner as possible . .
When you put the newly made half nuts on the slide put them with the uncut face towards the slide as there will still be a slight lead in on that face & the biggest chamfered edge . The lead in recess helps take/ keep any tiny bits of crud on the threads or face of the slide out the way , instead of it sitting under the nut face as it would if you put the new cut face there instead .
Using extra long 1 & 3/4 " Allen cap machine screws
I ground down a set of high tensile steel Allen capped screws to make the gib adjusting easy with a " T " Key/Allen wrench . By calculating how long they should be and putting one of the screws thread portion first in a collet set a, then ground the spigot/tit end as well as cutting it off .
