MILLING THE COLUMNS for THE BOLTON 9 MARINE ENGINE
by John
90% setup time, 10% machining.
The columns are tapered on all faces, so are difficult to hold, and difficult to measure.
I did a CAD drawing, to measure the taper angles, and to calculate some extra dimensions.
Then, in order to hold the castings in the milling vice, I made some accurate wedges at the appropriate angles (3 and 12 degrees) in wood and aluminium.
I actually progressed a bit further than the photos show, even roughing out the condensing tank.
The aluminium wedges have a 12 degree taper. The top wedge is sitting on a 10 degree and a 2 degree precision taper, giving an accurate 12 degree slope for milling. I made 2 such wedges, each 100mm long.
Unmachined casting on right. Partly machined on left. Quite difficult to set up, despite the setp up blocks at the appropriate angles.
johnsmachines 
Hi John,
here comment from far away, the Netherlands.
By chance I came to your blog. I am also a Triple to build and I’m obviously very curious how you will carry out further operations.
Possible that we can learn from each other to achieve a good result.
Greetings from the Netherlands.
Huib Hoogendoorn
hhhoogendoorn@kpnmail.nl
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Hello Huib,
I would be very pleased to communicate with you about our triple builds.
I have put mine aside for a while, due to other projects,and also because I am not happy with my method of machining the columns.
What stage are you at with your triple?
John
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