MS21916-6-4
Military Standard Boss Reducer
tube 3/8" to 1/4", reducer, external thread, flareless tube, carbon steel, MS21916 series fitting


Add to Quote
MS21916-6-4 Datasheet Features and Specification
Quick Specs
Thread Series | UNJF |
Thread Class | 3A |
Material | Steel |
Additional Information
Alternate Part Numbers
SKU / Model: | MS2191664 |
NSN: | 4730-00-541-4901 |
FSC: | Hose, Pipe, Tube, Lubrication, and Railing Fittings / 4730 |
Product Series: | MS21916-6 |
Pack Weight (Approx.) | 0.085 lb |
Minimum Qty (MOQ): | 1 |
Schedule B: | 7307.19.9080 |
ECCN: | EAR99 |
National Motor Freight: | 052190, Pipe,tubing,or Pipe Or Tubing Fitti |
Download PDF Version MS21916-6-4_Military-Fasteners-com.pdf |
|
![]() |
* report an issue on this page
Frequently bought together
Other customers frequently bought these along with MS21916-6-4

MS21902-4
Boss Nipple
in Fittings
outside diameter: 1/4", flareless, carbon steel, MS21902 series fitting
Product Image Gallery
Product code MS21916-6-4

Have a question
If you require a quote on this or any product please visit our quote request page »
Browse our frequently asked questions page.
You may contact us by phone at +1 (904) 543-6395 or
email us using our contact form.
Our hours of operation are 8:00am - 6:00pm EST
Customer Reviews

Another good experience with Military Fasteners, and our Sales Rep, Dan Hunter. We needed hardware for an older aircraft model, and Dan's expertise was exceptional. He quickly identified fasteners, even for parts with unclear descriptions, and provided invaluable technical assistance. The supporting data was spot-on, verified by our technicians. Despite finding slightly lower prices elsewhere, the unmatched service and expertise from Military Fasteners, particularly Dan, make them our preferred choice. Our order was delivered ahead of schedule. Highly recommend MilFast for top-notch service and technical support!
Hard to find bolts are never hard to find with Military Fasteners!
Fast friendly amazing to work with, some of my favorite people work there!!! First choice Always!!!!
10/10 love working with Amanda! She’s always eager to get on the phone with customers and ready to get their orders out the door.
Please complete this form if you're having an issue with ordering this item or this item displays invalid or innacurate information or specifications. We thank you for taking the time to report issues so that we may better serve you.