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Tapered tube plugs are a common, economical and effective way to seal leaking tubes.
Stocked in a variety of material and sizes.

Custom sizes and material available.

Boxes of 10 are standard. Part numbers are stamped on the back of the plugs.


Tube plugs are sized to fit tube diameters from 1/2 through 4 in. based on Birmingham and Stubs gauge system. Other sizes available on request.

Heat Exchanger Tube Plugs


Please indicate the following when ordering:

  • Hex Size

  • Plug thread diameter and thread length under the shoulder

  • Material

Standard thread diameters, Hex sizes and lengths in 1/8” increments:
3/4” with a 1” Hex—16 UNF Thread lengths 3/4” - 1” in 1/8” increments
1-1/8” with a 1-3/8” Hex—12 UNF Thread lengths 3/4” - 1-1/2” in 1/8” increments
1-3/8” with a 1-5/8” Hex—12 UNF Thread lengths 3/4” -1-1/2” “
1-5/8” with a 1-7/8” Hex—12 UNF Thread lengths 1” - 1-1/2” “
2-1/8” with a 2-3/8” Hex—12 UNF Thread lengths 1” - 1-1/2” “


Tube Size relationships to shoulder plugs:
5/8” Tube is typically a 1” Hex and a 3/4” threaded plug diameter
1” Tube has 1-3/8” Hex and a 1-1/8” threaded plug diameter
1-1/4” Tube has 1-5/8” Hex and a 1-3/8” threaded plug diameter
1-1/2” Tube has 1-7/8” Hex and a 1-5/8” threaded plug diameter
2” Tube has 2-3/8” Hex and a 2-1/8” threaded plug diameter 


Used primarily on fin fan heat exchanges this threaded plug is comprised of two parts. A threaded shoulder bolt and a gasket. The shoulder plug is available in a variety of material with Carbon and Stainless being the standards. Gaskets are typically carbon steel, however are available in stainless, brass, copper, soft iron or per your request.

Shoulder Plugs



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