Orifice Plates and Spectacle Blind Flanges

Colonial Machine has been manufacturing spectacle blind flanges in accordance with B16.48 for decades. Our stock of nuclear qualified carbon and stainless plate allows us to quote and supply the items you need. We also provide material and machining services to customer supplied dimensions or drawings of orifice plates for precision in flow measurement and restriction usage. Through our in-house capabilities and partnership with audited and approved suppliers, these can be manufactured to any size in standard usage.


Our orifice plates can be manufactured out of any standard plate and will be made to customer order. We can manufacture parts out of qualified or unqualified material we carry in stock, including but not limited to

  • A240 304/L or 316/L
  • A515 or A516 Gr. 65 or Gr. 70
  • A36; or A387 Gr. 11 or Gr. 22
  • all of the above available in a variety of thicknesses.

In partnership with our suppliers, we also source and perform independent testing on any material required by our customer, or machine customer-supplied material to required dimensions or drawings.

Orifice plate

“Thanks for being a partner for many years… Colonial has provided and advised us of any stub end needs for welding fittings.”

“Great company and great people.”

“We appreciate the relationship we have with Colonial.”

“You have always been very helpful and timely with your responses.”

“Great company and super people. Been doing business with Colonial Machine for over 40 years. Very knowledgeable.”

“Overall the customer service is very good.”

“It is a pleasure to do business with Colonial Machine.”

“Colonial Machine is a preferred partner for us as they are a great company to work with.”

“I have been working with Colonial Machine for the past 13 years and they are a very knowledgeable machine shop that can produce quality parts.”

“Honestly one of the best companies that I’ve dealt with in my 44 years in the business.”

“Colonial is one of our favorite vendors!”

“Customer service responds promptly and very courteous to work with.”