Oilless vacuum pumps are the noisiest. 2 stage HVAC vacuum pumps are fairly quiet and will provide the deepest vacuum.

I used them at work a lot. We also hooked up a micron gauge for that last inch of Mercury. 15 micron was the target.

If I was out to buy one, I wouldn't be afraid of what Harbor Fright has.

I'm probly going to let you down but, I swear I won't keep you down. John Hiatt