Aye Boyd,
Pleased to read that you have been 'rioting' and sorry to read that you stripped a thread!

A man of your paddock acumen should be fine! If your no taking the case off to do the job, just be aware that any swarf going in WILL end up in the oil gallery as SteveD alludes. So plenty of lardy grease on the end of your tap, especially the plug, afore you start and "little by little", rather than a clean tap and to the bottom in one!

Cotton buds (non-plastic handle variety!), again with plenty of sticky grease should assist with extraction as can a pair of eyebrow plucking tweasers

or dissecting tweasers, like those ones you used to have at school when doing dissection in 'O' and 'A' level Biology!

So far I have been spared the stripped thread on this lower 'Drain' hole, but have had to fit studs as per Dave#22's suggested methodology to the two upper mounting screw holes on an XT600E motor that I've rebuilt. Used 'StudLock' to hold them in place. The engine has yet to be run-up so I await to see whether it has been a success or not.

My regards, Bill