Suck it upMaking a Small Parts Vacuum FixtureIn my never-ending quest to actually get the Simpson and Shipton further along (there has been some progress, not yet posted) I’d been thinking about holding some thin parts for milling. This seems to take much more time than the actual milling. Double stick tape holds the part but coolant loosens it immediately. Crystal Bond is good but for a number of parts it gets tedious. Super glue, hot glue, etc.
A vacuum fixture plate seemed to be a workable solution. No special fixtures for each part, quick to set-up, quick to switch parts,etc.
The commercial plates are quite expensive. A search on eBay found some in the $100 range (without a vacuum system) but when I looked closely, they didn’t seem to be more complex than a grid of grooves to hold round gasketing and some connection to a vacuum source.
Might as well further amortize the CNC mini-mill. Enough ½” 6061 plate in stock so, off to Inventor for the CAD and the CAM.
The most difficult part was figuring out the connection from the pump to the plate. It seems that each industry has its own secret handshake, passwords and connectors. The HVAC and auto air-conditioning folks, who use vacuum pumps regularly, have a hither to unknown (to me) set of connectors. ½” ACME is not the acme thread that we know. It seems to be an HVAC connection.
A trip to the auto parts supplier netted a few adapters that got me from ½” ACME to ¼” NPT. The issue then was that my ½” thick plate was too thin to take anything larger than a 1/16” NPT. By some miracle, I actually had a 1/16 NPT tap, tapered reamer and die. Made up an adapter and all was well.
Rather than a group of photos, I thought I’d try a video as a change of pace.