Spacer Blocks For Edge Laps

When creating a grid to fit a given opening (like adrawer), I often want the spaces to be exactly the same. One way to do this is with asystem ofspacerblocks. This letsne avoid some potentially ugly math problems.

With this system there are two sets of blocks, see Fig. 1. One set represents the workpieces in the grid. (Ill call these divider blocks.) Another represents the spaces between the dividers (spacer blocks).

The goal is to get all the blocks to add up to fit the opening for the grid, see Fig. 1.

DIVIDER BLOCKS. I start with the divider blocks. These arecut from a scrap piece that has been planed to the same thickness as the dividers. You need one block for every divider — all with the same thickness.

SPACER BLOCKS. Once the divider blocks are made, the next step is to cut the spacer blocks. Don't worry about cutting these to finished length yet At this point, they should be oversize.

Now, stack the spacer blocks and trim them all to a consistent length, shavingjust a smidgen off with each pass. Between passes, test to see if the spacers and the divider blocks added together fit the opening.

POSITIVE STOPS. Here's the real payoff. When the blocks fit the opening, I use them as positive stops for the workpiece.

To set up the blocks, I place them all in a line so they're butted to the saw blade at one end, see Fig. 2. At the other end, I clamp a fixed stop block to the fence to keep the

blocks from moving.

Note: My tool of choice here is the radial arm saw. The table saw will work; it's just a bit awkward.

Cutting the edge laps is simple. To make the first cut, remove a spacer and a divider block and butt the piece against the remaining blocks, see Fig. 3. After cutting the fir: notch, remove another spacer and divider and make another pass. Note: The piece should never rest against a divider block.

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