If you don’t have a full shop with a vice and so on, it can be tough to make a nice clean square cut in stainless tubing.
We’ve been working to beef up the stainless on our dinghy davits in preparation for a new, very large solar panel. We could only get the new stainless tubing in half-foot increments, plus we wanted to dry fit it and mark exactly how long it needed to be. And we were reusing one old section of tubing to make two shorter diagonal supports.
That was going to be three cuts. The squarer we could make the cuts, the more securely they’d fit into the connectors and the stronger the overall structure would be.
Here’s the best way we’ve found to do it, working in the cockpit with minimal tools. We’ve tried using the Dremel tool to cut and found that while it would work, it would take forever. And we don’t have a stainless tubing cutter (a worthwhile investment for a bigger project but note that you have to have a tubing cutter designed for stainless, such as this one on Amazon, and it still helps to mark the tube and begin the cut with a file as described below so that the cutter doesn’t wobble and spiral).
So it’s a hacksaw for us. A new blade helps a lot. A full size hacksaw would also be faster than the mini one, which is better for working in confined spaces. Alas, we don’t have space for every conceivable tool on board and it’s a compromise.
Start by dry fitting the parts as much as is possible and making a small mark where it needs to be cut. A Sharpie or a piece of tape works well to make the initial mark.
Then we mark all the way around the tube, using a carpenter’s square to keep it square. You can also use one of your fittings if you have the type that encircles the tubing. We use a Sharpie to make the mark.
We’ve found that marking all the way around really helps in making a square cut as it gives a visual reference all through the cutting process.
Then we take a small triangle file and etch where we’ll start the cut. This is really important as it keeps the hacksaw from slipping.
Now we’re ready to hacksaw! With the blade in the groove we made with the file, we (okay, it’s Dave with me helping to hold) start slowly until we’ve got a straight line established.
As he cuts, Dave gets to a point where the tubing starts to V and bind the hacksaw. I’m usually helping to hold the tubing, and now I start holding DOWN on the outside end, but pulling UP with the hand nearer the cut. I’m not trying to actually lift the tubing, just keep it from V-ing down as Dave cuts.
Use a file to smooth the cut end.