Luiz Ally, Try Ally Tech, has a wealth of Utube videos on Sherlines and Sherline tooling. He built a low profile ,slim, vice for the Sherline. This is a slick vice so I looked around for some plans and found Nino Ransenberg put together a description and some dimensions to build Tryally's vice. This is in metric but I prefer the inch system, so using some of his dimensions I drew up a set of plans in the more friendly and usable inch system. My vice looks like this:

And the individual parts:

There are three main parts to the vice. The fixed jaw, L section, bolts down to the table via three socket head cap screws. These thread into one long and one short T-nut (bar). The fixed jaw has a key on the bottom to catch the T-slot so can't twist. It's held to the table solidly by tightening the three screws. The second larger part, the movable jaw, is also held to the table via a key, T-nut (bar) and two screws. It and the L section have a shallow "rabbit" where parts are held. A part is placed on the "rabbit" "shelf" on the fixed jaw and movable jaw. The screws on the movable jaw are made "finger tight". The third part, the clamp, also has a key, is held in place by a bottom key, with two screws to a third T-nut (bar). It is put in the table T-slot, as is the movable jaw, and moved up to the movable jaw. The clamp is then tightened to the table. The screw, horizontally through the clamp, is then tightened against the movable jaw thus clamping the part. Finally the screws of the movable jaw are tightened. We're ready to machine.

The only change I made from Tryally's design was to relieve the fixed jaw so a long part can overhang and be held. A very useful piece of tooling.