Musings

Solving the Sticking Legs

As we left our intrepid adventure, all four legs of the FORP workbench were bound in place, unable to move fore or aft.  The effort to seat them with a hydraulic bottle jack and the weight of the building was inadequate but that episode opened an avenue for contemplation.  Namely, how about constructing a frame to capture both the feet of the legs and the hydraulic jack against the slab top?

Brilliant! sez I, and I set about making one such device from oak 6x6s and framing 2x4s.  I placed the lower 6×6 cross piece underneath the feet at one end of the bench and captured the bottle jack with the other 6×6 above the slab.  Good concept, poor execution.  The corners were pinned with 1/4″ lag bolts, which almost immediately bent to such a degree that the unit was not functional.

For the next iteration I ripped a pile of surplus 3/4″ CDX plywood into 5″ wide strips, the fashioned them into a more robust frame what was three pieces for the stiles and seven pieces for the beams, all glued and screwed with four 1/2″ carriage bolts holding each corner together.

I held my breath as I maneuvered the bench and the frame to their respective locations, placed the bottle jack directly over one of the legs  with a metal bar at the top to transfer the force to the frame and started pumping the lever arm.  The results were almost immediate and immensely gratifying as I worked my way around the bench from leg to leg.  With each new stroke of the handle the legs would be driven into the mortises about 3/16.”  In about 30 minutes I had all four legs seated and a huge note of thanks for the person who invented the portable hydraulic jack.

At “peak compression” I noted that even the seven-layer beam deflected almost a half inch due to the force.

Finally the bench was on its feet, with zero wobble and clearly no need for glue in the joints.  I installed the stretchers and the shelf, and having already completed the game of Tetris required to move it where it was going and the six steps of moving other things to make it happen, including four other workbenches to new locations,  with two 8-foot workbenches being hoisted to the fourth floor, and the 450 lb. FORP bench slid easily to its new home.

I will wedge the through-tenons next week and true the top next spring after it goes through the winter in its new, heated home.  I have not yet decided what to do about spacing the holdfast holes, or installing the planing stop and leg vise.

Stay tuned.  At least I now own a killer hydraulic press frame.