Vacuum Chamber Construction

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Nicolas Krause
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Joined: Fri Sep 30, 2016 11:36 pm
Real name: Nicolas Krause

Re: Vacuum Chamber Construction

Post by Nicolas Krause » Fri Jun 29, 2018 12:44 am

After a bit of a school enforced break, I've finally managed to find some time over the summer holidays to return to the machining of my vacuum chamber. Using a carbide spot drill, a pilot hole was drilled and then subsequently enlarged to 3/8 size with a number of drill bits. I now plan on using a step drill to enlarge the whole to close to its final size and finally a boring head to take the hole to the precise diameter. The second hole visible in the photos below is from an earlier machining attempt that didn't work out.
I do however have a question about workholding. I'm using 4 toe clamps on a tilting table to hold my workpiece in place. The hemisphere seems to come loose rather regularly with the setup. After monkeying around with it for a bit I was able to find a seemingly stable solution that held the workpiece securely, but I wanted to know if there was a better way to go about holding the hemisphere. Or if I'm simply setting up the toe clamps in a way that doesn't use them effectively.

John Futter
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Joined: Thu Apr 22, 2004 2:29 am
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Re: Vacuum Chamber Construction

Post by John Futter » Fri Jun 29, 2018 8:00 am

Toe clamps directly to mill slide bed
t bolt through the hole in the top with machined aluminium disc to fit hole now held top and bottom you will need to offset mill head to correct angle to bore hole.


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