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The Pearls

The PearlsI believe Blum's The Pearls: Increasing Productivity in 32 Millimeter Cabinetmaking, written by Charlie Karp, predates all of the Blum Process 32 manuals. While the system starts with a balanced (12.5mm t/b start holes) panel and system registered 32m - g faces (14mm t/b reveals), the addition of a "B rule" messes it up. The B rule is that 14mm get added to the bottom of doors and bottom drawer faces (14/0 t/b reveals). Face sizes are no longer incremental and hinge cup boring is unbalanced (78.5/92.5 t/b). The presented drawer face registration is inconsistent because it only considers the bottom drawer face reveal. Because the presented drawer boxes are in 32mm increments, the top drawer face reveal is a constant, i.e. top registration works.

32mm system rows

The Pearls 6160_Pearls-layout_Metricks2.pdf (923.2KB, includes a few pages from "the stick" manual)

Drawer reveals and heights

Drawer reveals and heightsThe Pearls covers wood drawers a bit differently than I have. The information provided includes maximum box height and bottom face reveal numbers for various slides. I'm going to use the 230M bottom mount example to show the math for determining the top/bottom face reveals (see also) and maximum box heights.

Face offset minus box offset equals bottom reveal. The face offset is the distance from the system hole that the slide mounts to and the bottom of the drawer face. With system registration this is some multiple of 32mm - 1/2 of the gap between drawer faces, e.g. 32 - 1.5 = 30.5. The 230M has a 14.5mm box/slide offset so a 30.5mm face offset minus the 14.5mm box offset equals a 16mm bottom face reveal (bottom drawers have a 16 + 14 = 30mm bottom reveal).

The stated maximum drawer box height for the 230M slide is some multiple of 32 - 45. A typical top drawer is 157mm (5*32 - 3) and 5*32 - 45 = a 115mm tall drawer box. Subtracting the 115 box height plus the earlier calculated 16mm bottom reveal from the 157mm face height leaves a 26mm top face reveal: 157 - (115 + 16) = 26. All drawers in this system have a 26mm top face reveal (when using n*32 - 45 box heights).

Maximum drawer box height is a bit harder to calculate. I'm going to assume 19mm stock and stretchers/rails between all drawers. This means that the minimum drawer opening is n*32 - 9,5*2 (rails center on system holes, -9.5 top and -9.5 bottom). Using the same five increment example, 5*32 - 19 = 141 opening.

With system registration, the distance to the first system hole from the bottom stretcher/rail is 22.5mm (32 - 9.5). Subtracting the 14.5mm 230M box offset leaves 8mm betwen the box bottom and the rail/stretcher (VS the 4mm minimum specification).

The 230M specs say that the minimum top clearance is 16mm (or 15, depends on the drawing). Using the 141mm opening and subtracting 16mm from the top and the earlier calculated 8mm from the bottom leaves 117mm (141 - 16+8). Subtracting 117 from 160 (5*32) leaves 43mm. The maximum height for all drawers (in >= n*32 - 19 openings) is n*32 - 43.
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