Improved Pipe Clamp / Vise Release Mechanism

[ARCretired]

Upgraded version of the pipe clamp / vise release mechanism.
I decided to make an improved version of my bench / storage cart for my son in law for Christmas. (See my earlier post – SS accessory cart & bench). I learned a few things making the first one and thought I would share with anyone who is thinking about using pipe clamps to make some version of a bench vise. In this version, pipes are supported and positioned by a center plywood section and the bench ends. The pipe clamping ends are only used to clamp or release the pipe, not to support them. They are loosely trapped in place by the pipes and the surrounding wood structure. The center wood section and the bench ends were drilled (1 1/8” diameter) together for pipe alignment. Also drilled the holes for the bushings with the wood stacked together for alignment.

The pipe clamp release mechanism is made from purchased hardware. 3 bronze bushings were pressed into the sides and middle wood sections to support the 3/8” threaded rod. The bushings allow easy rotation and sideways sliding of the rod. The rod is allowed to slide about ¾” of an inch to release or lock the clamps. A lock nut in the center of the rod and the knob lever limit the rod travel. The knob and lever are rotated to engage and release the clamp steel sections, then slide sideways toward the bench to engage the bench side to keep the clamps released. The spring action of the pipe release tensions the knob / pin in place until it is pulled away from the side of the bench. Once it is pulled, the knob lever, rod and internal levers and bolts can rotate, freeing the pipe clamps to lock the pipe.
Only modification to the pipe clamp ends was to remove a small cast iron section to make room for the threaded rod.
Material list:
2 ¾” Irwin pipe clamps
¾” pipe I had the hardware store cut a 10 foot pipe into 2 40” and one 38”pieces. I had a left-over piece from my earlier project for the 4th pipe.
3/8” threaded rod
11 - 3/8” nuts
8 - 3/8” lock washers
3 keepers from 3” U-bolts for the levers
3 - 3/8” ID, ½” OD, 3/4" long bronze bushings
2 - 5” 3/8” bolts
1 plastic knob with 3/8” end
1 – 3/8” threaded rod coupling
1 - 3/8” washer

See pictures for details. Pictures shown vise pipes (outer 2) and also pipes (inner 2) for an bench extension on the opposite end of the bench.