Measuring a Tank

Measuring A Fuel Tank

Keys to Remember

Length is measured weld seam to weld seam
Fittings are measured from lateral weld seam center of fitting and end cap weld seam to center of fitting
Indicate which end of the tank is toward the front of the truck and whether it is on the driver or ditch side
Mark desired finish (milgrade – brushed aluminum or polished – like chrome)
Use flat measuring tape if possible
Measure tank from same location as you would when filling the tank (not from sitting inside the cab)
Refer to the bottom of the page to determine correct NPT fittings

Finding the Thread Size You Need

To determine the size of pipe fitting thread you need, first use a tape measure or caliper to measure the inside diameter (ID) of the threaded hole where you would like to install the fitting or the outside diameter (OD) of your existing fitting as shown below.

After determining your measurement choose the closest ID or OD dimension listed in the chart below and select your pipe thread size. (Dimensions shown are approximate values and you may need to round up to the closest value).

Threaded Fitting OD or Hole ID Measurement	Pipe Fitting Thread Size
3/8"	1/8" Pipe
1/2"	1/4" Pipe
5/8"	3/8" Pipe
3/4"	1/2" Pipe
1	3/4" Pipe
1 1/2"	1 1/4" Pipe
1 3/4"	1 1/2" Pipe
2 1/4"	2" Pipe

Common Pipe Thread Sizes for Fittings and Plugs

Pipe Size	Threads per Inch (*NPT)
1/8"	27
1/4"	18
3/8"	18
1/2"	14
3/4"	14
1"	11.5