I have looked at the headstock drawing and it shows the hole in the headstock fitted with two grub screws for retaining the headstock oil channel. The other hole seems to show an oil nipple fitted, presumably for lubrication.

You are right about it being the "other hole" because the one to which you refer is in an-other part altogether.

The oil nipple is in the clutch housing. The grub screw to which the OP refers is in the front spindle bearing cover.

In a later manual (from SER 3311, diagrams CHIP-01-70 and CHIP-02-70) the longer grub screw goes into the headstock casting first. The shorter one on top of it is presumably to act as a lock bolt so the one below does not back out due to vibration.

The front bearing cover in the manual shows no grubscrew, but the item 1146, labelled 'peg' looks too coincidently to be in the same general location as the grubscrew for them not to be related.

In every Chipmaster I have seen, in both locations, the factory paint has been applied over the grubscrews.

Hi Steve

Could be helpful for you to join the Colchester group at iO Groups, there are likely Chipmaster owners there who may be able to answer any future questions, join at this link:
**LINK**

Emgee