- Practical advice
- The mechanism
- The tray
- Screw, flat iron, claws: the material
- Train the carriage of the mobile claw
- Milling the screw holes
- Lay the plate
- Dig at the router
- Milling the embedding of the plate
- Adjust the housing of the mechanism
Important accessory of the cabinetmaker's workbench, this press, also called "rear" although located on the side, is used to maintain parts flat without using a jack. Contrary to its cumbersome "Parisian" sisters, it can be installed after the event without changing the set: an irreversible operation, often approached with apprehension.
● If the pad is not removable or if you prefer a more efficient digging, although less discreet, open frankly the underside of the tray to pass the mechanism and just a cylindrical end hole for the screw.
● Close the opening with a piece of wood with a symmetrical light to the groove so that the claw can sink completely and the chips are removed. The truck must not tip over when there is no claw.
First envisioned with a jack screw, the mechanism is finally made from an old cart drag screw, fitted with a few pieces of 6 mm flat iron. Its nut is transformed into a mobile claw support trolley, and its frame replaced by two fixing plates: a large side crank, a small at the other end. The first will be threaded on the shoulder opposite the original to counter the clamping force. Claws are commercial models, but could be made from a steel or aluminum log and equipped with a piano wire spring.
The two lugs of the brake nut are cut to the angle grinder to obtain a cube. Two flat irons are welded instead, 26 mm overhang on the same side. Their ends are connected by a third iron delimiting a wide space of 20 mm, where will pass the claw. The mounting plates are respec-tively 6 x 30 x 65 mm and 6 x 60 x 80 mm.
A drill press, or a portable power tool with a very slow speed, is needed for larger holes. The diameter of the passage of the claw in the carriage is, in fact, 20 mm, those of the screw in the large and the small plates of 18 and 12 mm.
The large plate has a screw hole of 5 mm at each angle. The other has only two, side by side, at the base: its upper end will be taken in a groove cut in the wood. A countersink allows to house the heads of the screws VBA.
After drilling, the edges are broken then the polished surfaces at the grinder equipped with a flap disc. The ends of the trolley must be perfectly smooth to slide in the wood without hurting it, and smoothly. Once degreased with a lean solvent, the parts are painted to protect them from oxidation.
The location of the groove of the moving claw is delimited by presenting the screw on the workbench. Groove and claw holes are machined at the router with a straight plunging cutter ø 20 mm. The shoulders under the groove (in the tray) are cut with the same strawberry, whose tail serves as a pilot: be careful not to burn the wood! The holes are finished at the crankshaft.
The opening on the underside is reduced to the strict minimum. The workbench is placed upside down, the tray is milled with a template and the router equipped with a copying sleeve. After removal of the pad, an opening of the section of the carriage is made at the end of the tray. First, it allows the digging to continue with a long chisel or shoe, then to engage the mechanism, fixed in place by six VBA screws of Ø 5 x 50.
It remains to drill into the mattress the passage of the screw and to machine the housing of the large plate. If the reach at the end of the screw is long enough, this housing can be cut in the tray itself. Finally, the pad is attached to the polyurethane glue.
Screw, flat iron, claws: the material
Apart from the two claws, bought, the mechanism is made from recovery elements: a cart brake screw, a few flat iron drops of 6 mm, and six screws of 5 x 50 mm.
Train the carriage of the mobile claw
The pins of the brake nut are removed and their position leveled at the grinder. Two legs replace them, connected by a third flat iron, all forming the carriage of the mobile claw.
Milling the screw holes
Large diameter holes require a fixed drill, slow and high power. The screw holes are milled. A machining table, not essential, facilitates positioning.
Lay the plate
The mechanism is finished. Side crank, the new plate is placed on the face of the shoulder opposite to that of the original support. A layer of paint protects the parts from oxidation.
The groove and holes of the fixed claw are aligned by guiding the router against a ruler. The machine is also wedged by a stop to make the holes, which is completed at the crankshaft.
Dig at the router
To control the size of the wood, the housing of the mechanism is dug to the router (with template) and then adjusted by hand. The passage of the end of the screw is opened using an elongated wick.
Milling the embedding of the plate
In anticipation of this equipment, the tray mat had not been glued. This allows disassembly to mill the recess of the plate and thus limit the projection of the crank.
Adjust the housing of the mechanism
The housing of the mechanism is adjusted around the carriage, resulting in a delicate machining that requires long scissors. Otherwise, open more widely and close with a piece of wood of the same essence.