Well today's effort was to start rebuilding a set of twin HS4 carbs
After researching "How to re-bush the throttle body" i went the Chucking reamer path
That is i bought a 9.5mm chucking reamer, then set it up in my $100 Hercus Cylindrical Grinder and ground the shank down to 0.3125"
Then i back ground the flutes next to the shank to allow the reamer to cut backwards
Using the shank as a pilot through the 2 bushes i used a cordless drill to turn the reamer to cut the new holes
it was the easiest way to ream out the worn holes to fit the new split bushes supplied in the rebuild kits
I then bead blasted the bodies, external parts only.
Bead blasted the Manifold as well to make it look nice
Next is the HP Air Cleaners
How the reamer does the job
The reamer in the grinder
The carbs bead blasted and nearly re-assembled
My $100 Cylindrical Grinder
Good value, like my $100 Myford Super 7 lathe was. 