Vacuum Puck Assembly
These instructions are for assembling daisy-chain vacuum pucks from 3/4" x 4" x 4" plastic blocks . The instructions are provided for anyone who wants to build their own vacuum clamping system. Please note that you may need to adjust hole sizes and/or measurements to suit the particular hardware/materials you're using.
The blocks should be a non-porous plastic that isn't brittle. UHMW (ultra-high density polyethylene) or HDPE (high density polyethylene) are good choices. The weatherstripping should be of the closed-cell foam type. An open-cell foam won't work, so check the package before you buy.
I use sharp carbide-tipped lipped brad point drill bits (from Lee Valley Tools) and a medium-size drill press vise. I run my drill press at the same speed I use for drilling wood; and my results are consistantly good.
I cut the stripping with a single-edged razor blade and discovered that it's important to make square cuts so that the corners mate and seal properly. Cutting and placing this stuff is the most exacting part of the whole job. A little time invested in doing a really good job now will save a lot of time later on.
Drill a 5/16" hole straight through each block at the exact center of the 4" x 4" face.
There must be no gap where the strips meet at the corners to cause air leaks. Take your time and work carefully. When you've finished, recheck all of the corners on both top and bottom of all blocks. Adjust the foam strips as necessary to eliminate air leaks.
Congratulations! You're done.
If any of the valves marks a workpiece, press it out of the block from the bottom with a 1/4" dowel, then ease the edge of the hole slightly with a countersink or sharp knife and reseat the valve.