I made a horizontal bar attachment for my Versa-Vise.
I don't like the stock part available for these vises, because it 1) locks in place with a set screw and 2) sits too low, which doesn't allow much movement. This one is a collar type and is very secure. It is a standard 1.5" drum rack tubing connector made of aluminum. It seems strong enough. They come in a variety of designs, but are often plastic, something to keep in mind. The horizontal piece is 1.5" DOM steel tube that I had to turn down a little (~0.3 mm) to make it fit easy into the vise. It could have been easily sanded down too.
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