ATOMATIC 5

5cc ITALIAN BEAUTY

Part five - Carving - by Ramon Wilson

Next up was to tackle the lower end.

First off was to get rid of the feet and some of the waste...

Using a 6mm FC3 with the corners rounded off the  profile was milled in a series of flats - one full turn of the dividing head - the stop point was worked out for each side (the blue mark) so as to leave enough for final fettling by eye.
The outer rear dimension was sized using that long series mill - two steel discs had previously been turned for later use to the rear and front dimensions (41.00 and 40.00) and these had registers on that located the bore. The disc was held in situ and the cutter touched on then backed off 0.1mm and the stop set. The front end was done likewise using a long series 1/4 slot drill extended as far as dared - a bit whippy but it did the job.
Finally 'chipping' away by eye as much as dared with a 1/4 ball nose.
The second case was then brought to the same stage before repeating the exercise but with the dividing head set a minus 1 degree to give the 2 degree included taper on the lower case.

First off was to prove the angle and ensure the cut flared out at each end.

The case was then cut as before but this time with half turns of the dividing head to give much smaller flats.
The discs were then bolted on ready for the shaping.
First off more tape protection - really important here as any ding into the case above would be very difficult to disguise.
Then the fun begins. Taking your time and not applying anything more than light pressure is the key here, letting the tool do the work just slowly chipping away.
You can see why there's a need for three layers of tape here! This is the first stage taking it down to the thickness of the tape and getting the basic shape.
Ready for the second stage - an even steadier hand and slower approach required.
The temptation to go to far has to be resisted - it's much better to have to file for a bit longer than go 'over the line'.
It took about an hour and a half to file it out and another half to fine tune and polish it down with 240 grit emery, 400, 600 800 grit wet and dry and a final rub with medium and fine Scotchbrite.
Then it just remained to 'do it again'.


part nine  part ten   part eleven   part twelve