I had to make 10 sight glasses for Dolikeadrink's monster column, to get them all the same height and profile to surface mount on the 4"columns, I decided to use the angle grinder method with a 4"grinding disc to cut the profile.
I got some brass unions, being a threaded cylinder with threaded coupling which screw into each end.
![001.JPG](./download/file.php?id=42010)
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With one of the screw fitting screwed in I then cut off the hex.
![003.JPG](./download/file.php?id=42011)
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The face of this fitting provides a good flat surface for the glass and seals.
![007.JPG](./download/file.php?id=42012)
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Now with the other fitting screwed right in, I put it into the small vice I use for my drill press, which I have marked to get the position right every time, this now fits into my angle grinder attachment to cut the required profile.
![005.JPG](./download/file.php?id=42013)
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After cutting the "meat"out of the fitting, a final skim across with the grinder will give a perfect surface to mount on the column
![005.JPG](./download/file.php?id=42014)
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It means I can make all ten fittings the same height and with a profile to fit the column perfectly.
![006.JPG](./download/file.php?id=42015)
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I will then tin the ground surface with a heavy coat of silver solder, position on the column, and then apply heat to the column until it melts the tinned solder again providing a perfect clean joint, I then drill through the fitting with a hole saw on my drill press to make the hole through the fitting into the column.
OD
OLD DOG LEARNING NEW TRICKS ......