
V-21A
SETTING UP AND WELDING
9
Fit the stud and ferrule in place and set the
required burn o protrusion. This is achieved
by using a 5mm hex key to loosen the leg
clamps in the front end cap.
Aer loosening the clamps, slide the legs in or
out unl the desired stud protrusion is
achieved (this amount will vary from stud size
to stud size and is generally proporonal to the
stud diameter).
NOTE! In the BS EN ISO standard covering the
manufacture of drawn arc weld studs, the
length prior to welding (this is the length aer
welding plus the burn o allowance) is at the
discreon of the stud manufacturer.
Dierences in this length would impact on the
burn o protrusion value.
As a general rule of thumb, we would suggest that the burn o protrusion distance should
be approximately 8 to 10mm, but never less than 7mm.
Once the correct protrusion is set, you must
ensure that the movement of the stud inside
the ferrule is smooth, as any binding between
the stud and ferrule will result in poor or bad
welds. As can be seen in the accompanying
illustraon where the foot piece is shown with
some of the fasteners missing, the holes in the
foot piece are a lot bigger than the screws
fastening the foot piece to the legs. This allows
the foot piece to be adjusted to remove any binding between the stud and ferrule. Once
these condions are sased, you are now
ready to set the li.
IMPORTANT!
It is necessary to check/reset the protrusion
and posioning of the foot adaptor when
changing stud lengths/diameters.
SETTING THE LIFT
Adjustment of the pistol li is achieved by removing the rear end cap of the pistol. Inside is
an adjuster with a large slot. Use a coin to twist the adjuster. Clockwise rotaon reduces li
and conversely an-clockwise rotaon increases li. The adjuster has a “click” detent, each
click is approximately equal to a 0.25mm change in li.
Li should be set between 1mm and 8mm depending on the size of stud being welded and
other applicaon specic factors e.g. material, site condions etc.
BURN OFF PROTRUSION