I use a pair of small C-clamps on the clear tubing. Tighten them down just until the needles quit bouncing. Works great. Switch them to double check.
Edit- Bought mine
here. Page 575. Item number 3935k52 (on home page scroll down to the third section "Process control and instrumentation" and click on "vacuum and compound gauges") Price has gone up a bit in a year and a half. They have all kinds of stuff. Bought a set of metric feeler gauges while looking for the page.
