Engineers of a nervous disposition may want to look away...
So lets say you have a Rover V8 that you fitted skimmed cylinder heads to. Cylinder heads that you didn't know how much they were skimmed by...
... and now the inlet manifold doesn't fit, so ideally the two inlet faces of the heads skimmed, or if you've already fitted the cylinder heads then the two faces of the inlet manifold need skimming.
And you're broke so getting it machined is out of the question.
Take one cast iron surface table that weighs half a tonne. Its been a while... needs resurfacing. :|
Scrape off surface rust, then spend a long time resurfacing it, checking it with a straight edge and feeler gauge. Few low spots, but then this came from a welder who used to tack things to it and beat it with hammers... poor surface table, it was abused in its previous life. Don't worry little surface table, you're being taken care of now.
Even surface tables need feeding... 20W50 should do it some good.
Right then, what does a very flat cast iron surface table have to do with skimming an inlet manifold I hear you ask? Well... contact adhesive, first 80, then 120, then 240 grit sandpaper.
Before...
The beginning of a long process...
Mark up what you want to remove...
Then spend a long time pushing and pulling the inlet manifold backwards and forwards. If you can get someone to supply with copious amounts of tea and food, it saves you 10 minutes every few hours getting it yourself.
Fitting the ram housing distributed the weight better over the surface table.
Almost there!
Check it with a straight edge and feeler gauge, then deburr the edges and profusely clean the inlet manifold and ram housing, you
do not want very fine aluminium particles being sucked into your nicely new rebuilt V8. That would be bad.
Then do the other face...
Please forgive me.