Arc Machines 307 - Manual (Page 146)

Arc Machines, Inc. Model 307 Orbital Tube Welder Training
Document No. 740096 Chapter 14. Page 2.
Rev. A
In the drawing from Table DT-5 of the BPE Standard, the B dimension is the
Squareness face to Tangent which increases with tubing size. The Tangent
length (T) is defined as the straight length measured from the welding end. T
varies from 1.50 in on 1/4 inch O.D. tubing to 2.50 inches on 6 inch O.D.
tube. The Control portion, C, is defined as the length from the welding end
over which tolerances for wall thickness and O.D. are maintained. The length
of the control portion is fixed for all sizes at 0.75 in. (19 mm).
Cleaning/Surface Condition
Weld components must be clean in order to achieve good weld results. Clean-
ing procedures vary with industry and application, but the BPE standard in
part DT-12 Surface Condition states that
“Internal and external surfaces of fittings and
process components furnished to this Stan-
dard shall be cleaned to remove oils, grease,
particulates, and grinding componds or elec-
trolytes”. When such fittings are packaged,
the ends are protected with end caps and fit-
tings are sealed in plastic bags or shrink
wrapped. The installer is responsible for
maintaining cleanliness of components dur-
ing the installation and for the condition of
tubing that is cut and prepped on site.
Drawing for Table DT-5 Final Tolerances for Mechanically Polished Fittings and Process Com-
ponents from ASME BPE-2002. Reprinted with permission from the ASME
A facing tool used to produce
machined ends on small diameter
tubing.