When you need to verify pressure instruments in a process measurement setup, a dead weight tester is the reference standard many shops trust. The catch is that a working calibrator can cost thousands. So an AMETEK at $349.99 catches the eye. But this particular RK-300 comes with a serious caveat: it is sold as-is, for parts or not working, and has not been tested. Is it a smart buy for your calibration bench or a money pit?
Quick verdict
For most buyers, this is not a ready-to-use calibrator. It's a project unit. If you are a technician who can inspect, clean, and recertify vintage dead weight testers, or if you specifically need spare weights and hardware, the accessories alone might justify the price. If you need a working reference standard tomorrow, keep looking.
AMETEK Mansfield & Green RK-300 Pneumatic Pressure Tester Dead Weight Calibrator
What you are getting: The package includes the RK-300 pneumatic pressure tester with a set of precision weights, braided stainless hoses and fittings, inlet/outlet controls, a high/low range selector, a bubble level, and a carrying case. Unit markings identify it as an AMETEK Mansfield & Green Division model with serial number 84993, maximum supply pressure of 450 PSIG, and an accuracy rating of 0.015%. The gravity compensation marking 980.665 suggests it was set up for a specific location.
Who it suits
This is for someone comfortable with dead weight tester operation and calibration. If you have a calibration lab or a shop that already services pressure instruments, you can treat this as a core-plus-spares kit. The weights alone are often the most expensive part to replace, and hoses and fittings are useful even if the main body needs work.
Meaningful trade-offs
The big unknown is the condition. The unit is explicitly sold for parts or not working, with no testing done. There's no warranty or return promise included, so you are accepting the risk that the tester may need significant repairs. Vintage equipment like this can still be serviceable, but seals, valves, and the dead weight piston could be worn or damaged. Also, this is a specialized pneumatic tester, not a general-purpose gauge calibrator. You need to know whether the 450 PSIG max supply pressure and the included weight range match your application.
Bottom line
At $349.99, you are taking a calculated risk. If you already have the skills and the test equipment to verify this RK-300, it could be a way to own a precision reference standard at a reasonable upfront price. If you are not prepared to troubleshoot, the price is too high for a decorative paperweight. Buy it only if you have a concrete plan to bring it back to service.
