This is a worthy little water pump which you could use in a bind. If you are somewhere where you don't have power, it would be a cool little thing to have on hand for emergency purposes, just in case.

wolfcraft Universal Drill Clamp, Die-Cast Aluminium

I've seen a very similar thing done with 1/2" carriage bolt and plastic big box store knob. See here: https://www.youtube.com/watch?v=gpFAE0WgoeE. I have lots of experience with T-bolts and they are easy to use and work well for clamping. The safety clamp shall be used for an entire string if the Casing/Tubing/Drill pipe is flush, meaning no upset or coupling.Understanding the operation of the slips will make you understand the purpose of the safety clamp. Why do we use it in our daily operations on the drill floor, whether we run Drill Pipe, Casing or Tubing? Once we've done this we'll use a cotter pin through the hole and bend the ends...but don't do what I did and assemble the knob onto the bolt without first running it through the toggle clamp (from the last step).

Drill Press Clamp : 11 Steps (with Pictures) - Instructables Drill Press Clamp : 11 Steps (with Pictures) - Instructables

Beyond that, we're going to fit a nut into the bottom end of the toggle clamp by carefully grinding out a channel for our nut to fit into. We'll fit it to the underside without fear of it being jarred loose as upward pressure will keep it in place. Besides just the upward pressure, we'll use some sort of metal epoxy mixture to glue it into place. Now, I've made a couple of these (one with the metal epoxy and one welded), and have to admit I'm more partial to the spot welded nut, but the epoxied nut hasn't failed me yet.As the name states, it is a “safety” device. It’s an extra effort to prevent a single joint or a complete string of pipe from dropping down the hole.