maknwar has the Ideal needle valves for sale. I have used Clippard, Azoo, Swagelok, Nupro, Whitey, and Parker needle/metering valves and for the money, the Ideal "1" series are great for our purpose. This model's Cv offers a wide range of adjustments. It is true that most of the low flow models of metering valves (like
Swagelok's "S" series) will work, but many come with tubing connections and not 1/8" NPT ports like the Ideals do. These tubing connections require specific parts from the manufacturers in order for them to be adaptable for our use. There are a few medium flow metering valves (like
Swagelok's "M" series) that will work for our use, but their flow rate adjustability might be limited to the first quarter to first half of a turn out. You can usually find many of these with 1/8" NPT threads. There are some of these medium flow metering valves that work better than others because of differences in their Cv. Under no circumstances that I know of can
Swagelok, Nupro, Whitey, and Parker
NEEDLE valves work for our purpose. Their Cv is much too high and/or their adjustment range is much too short. With these manufacturers above you want to look at their
METERING valves and not their
NEEDLE valves. Ideal makes
NEEDLE valves.
These are the "1" series of Ideal needle valve that many of us use
http://idealvalve.com/ :
52-1-12 (brass, knob handle, angle flow)
V52-1-12 (brass, Vernier micrometer handle, angle flow)
52-1-11 (brass, knob handle, straight flow)
V52-1-11 (brass, Vernier micrometer handle, straight flow)
if you want stainless steel valves, substitute a "54" in the part number for the "52"
You can also call Bill Sand at Ideal (701) 352-1164 to place an order directly from the manufacturer. You can email him too, but sometimes he is behind in answering his emails.
[email protected] 
Where to buy ideal needle valves 
Linear Mode
