INTERNAL HI-LO Gauge Four quick step check internal alignment. You can check the internal alignment of your fit-up with HI-LO gauge.
1. Unlock the retaining screw. Press the gauge legs beyond the barrel.
2. Insert the legs (wires) into the root gap space of the two pieces of pipe to be fitted. Turn the gauge 90 degrees, being careful to apply a constant back pressure to the barrel.
3. Hold the gauge as square as possible with the fitting to obtain an accurate reading. Lock the retaining screw. Reverse the 90d turn and remove the gauge. You're now ready to read the increment opposite the red line.
4. When the red line aligns with the 1/32" increment you have a good internal alignment and fit-up. Misalignments can be determined.