41 - Fold-Down Drafting Table, страница 20

FEATURE PROJECT

PIVOT SYSTEM

THREADED ROD SLIDES DOWN SLOT AND KNOB LOCKS TABLE

©SUPPORT PIVOTS ON ARM TO EXTEND TABLE OUTWARD

ARM FOLDS DOWN TO PROVIDE SOLID SUPPORT FOR TABLE

Pivot System

The heart of the drafting table is a simple pivot system. It lets you swing the table out of the case (or fold it up). And it provides solid support for the table when it's open. To make this work, the pivot system consists of two main parts: a pair of supports and two pivoting arms, see drawing at left. supports. The supports (0) are narrow pieces of hardwood attached to the bottom of the table, refer to Fig. 4 on next page. Two holes in the sides of each support are used to connect it to the case and the arm.

To provide clearance as the table folds up and down, you'll also need to cut a radius on the outside corner of each end of the supports. Then just glue and screw the supports in place.

arms. Next, i added the two arms (P), see Fig. 5. The arms pivot at each end. So you'll need

to drill a hole in each place for a" bolt that acts as a pivot pin, see Fig. 5a. Here again, cutting a radius on both corners of the upper end only provides clearance as the arms pivot.

attach arms. Now you can attach the arms. This is easy for the upper (curved) end of each arm. It's fastened to the support with a carriage bolt and lock nut.

But there's a bit more involved when it comes to the lower ends of the arms. That's because they're attached to the loiver panel that was made earlier.

To create a uniform Vs" gap between this panel and the table, I slipped Vs" hardboard shims between the two parts. Also, placing scraps of V4¹¹ hardboard under the assembly keeps it level and "snugs" the lower panel against the arms as they're screwed together.

mounting blocks. The next! step is to add two hardwood mounting blocks (Q), see Fig. 5. These blocks are attached to the

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No. 41