sure that all tube material and tools are kept free of oil
and grease. Use the tube flaring tool (fig. 10-37) to
prepare tube ends. Check tube end for roundness,
square cut, cleanliness, and make sure there are no draw
marks or scratches. Draw marks can split the tubing
when it is flared.
Use a deburring tool to remove burrs from the
Figure 10-38.--Tube position and resulting flare.
inside and outside of tube. Remove filings, chips, and
grit from inside the tube. Clean the tube. Select the
always be accomplished with a presetting tool, such as
proper size die blocks, and place one-half of the die
the one shown in figure 10-39. These tools are
block into the flaring tool body with the countersunk
machined from tool steel and hardened so that they may
end towards the ram guide. Install the nut and sleeve,
be used with a minimum of distortion and wear.
and lay the tube in the die block with 1/2 inch
NOTE: A flareless-tube connector may be used as
protruding beyond countersunk end. Place the other
a presetting tool in case of an emergency. However,
half of the die block into the tool body, close latch plate,
when connectors are used as presetting tools, aluminum
and tighten the clamp nuts fingertight. Insert the upset
connectors should be used only once, and steel
flare punch in the tool body with the gauge end toward
connectors should not be used more than five times.
the die blocks. The upset flare punch has one end
counterbored or recessed to gauge the amount of tubing
needed to form a double lap flare. Insert the ram and tap
lightly with a hammer or mallet until the upset flare
punch contacts the die blocks, and the die blocks are set
against the stop plate on the bottom. Use a wrench to
tighten the latch plate nuts alternately, beginning with
the closed side, to prevent distortion of the tool.
Reverse the upset flare punch; insert the upset flare
punch and ram into the tool body. Tap lightly with a
hammer or mallet until the upset flare punch contacts
the die blocks. Remove the upset flare punch and ram.
Insert the finishing flare punch and ram. Tap the ram
lightly until a good seat is formed (fig. 10-38). Check
the seat at intervals during the finishing operation to
FLARELESS FITTINGS.--Preparing tube ends
for flareless fitting requires a presetting operation
whereby the sleeve is set onto the tubing. Presetting is
necessary to form the seal between the sleeve and the
tube without damaging the connector. Presetting should
Figure 10-39.--Presetting flareless-tube assembly.
Figure 10-37.--Tube flaring tool (double-flare).