The club (akakraft e.V.) who runs the workshop I’m using is holding “work days” on a regular basis. The workshop is cleaned, maintenance of the machine park is done, light bulbs are changed and new hardware is installed. Some time ago a extraction system for exhaust gases was donated. Today we started to do the piping. There already is a hole in the outer wall at a convenient place but the pipes used are 11cm in diameter and the hole is 17cm. Where can we get a adaptor? This doesn’t sound like a part which is available everywhere.
I LOVE such tasks. Just take your measuring tape and roam through the workshop or a hardware store and look for stuff which might help. Great training for your skills in visual judgement of dimensions as well. Obviously I started searching at the scrap box since it’s full at the moment and there’s always good stuff. And Bingo! A five liter keg of a rather well known beer which doesn’t really taste like much. It’s conical as well so it will be a snug fit. It only needs two holes of the right size. Normally you would start to mess around with pliers to get it done somehow in a fast and dirty way. But that’s not how we do it. Everything has to be over engineered, look nice and the fabrication process has to involve fancy machinery. 🙂
On the bottom we just marked the center with a center bore, adjusted the turning chisel to it, zeroed the scale and measured outwards.
Since the top already has a small hole we started on the outer diameter, zeroed the scale and measured inwards.
The first hole was a perfect fit. You could slip it on the tubing easy and it was difficult to remove it again. The second hole was a little off but still alright.