Thanks again Gents, much appreciated. Ralph, you're right, even without polishing it seems to be acquiring little scratches and dings.....
still, it looks great from a distance, which is what matters...
Anyway, as you may recall, I'd planned to do one final little skim of the bottom, just to take the bow out of it. Well, didn't I nearly wreck the thing? Here's a Very Important Lesson - actually, TWO Very Important Lessons - both of which will rightly attract censure from all quarters....
Lesson 1: If you put the tool in the collet the night before, the following day when you make the cut,
make sure the damn thing is tightened up properly!
Yep, the cutter started to unwind itself as I put the cut on, which made the cut deeper.... and deeper.... and deeeeeper......
Lesson 2:
NEVER, EVER EVER! walk away from the mill until you're ABSOLUTELY sure everything's tight, cutting properly, etc.
In theory, I know, you're not supposed to walk away at all; but in practice, when you're taking a 10 thou skim at about 2 inches/min, the "do something else" factor is quite high, and is normally no problem.
I heard the cut getting worse, and returned immediately, but by then the damage was done, and the cutter had dropped a full 1.5mm AARGH!
So, that 10-20thou skim becomes a 1.5mm skim. Hey ho, at least it'll be lighter. More annoyingly, the vertical bolt holes, carefully drilled & tapped M10, are now all 1.5mm out of position, which means the sump can't be bolted to the gearbox! Argh!
Therefore, the rescue is as follows:
- Finish the skim, re-check on engine (it still all clears, without the gasket in place so I must have added some extra clearance earlier - as Stew says, a little clearance never got in the road.
- Turn down some ali & thread M10. Screw into gearbox threads with loctite & mill flush.
In order to re-locate the bolts, I decided to do something different.... The gearbox has nicely machined holes for the bolts to go through; so, I turned a piece of ali down to diameter & drilled the centre 6mm; then turned down a piece of steel to 6mm and turned a point on the end. The result is a made-to-measure marking punch that will be straight & true every time:
The sump is now on the engine, the next job is to take the engine off the stand, get the gearbox mounted up, punch the marks, drill & tap the holes, & send it on it's way!
