G-10 Epoxy Glass Laminate Rotary Torch Guide Tube, Turn-Milled with Deep Hole Drilling

About This Part

This tube guides a miniature rotary welding torch, and the material is the design decision. G-10 epoxy glass laminate is an electrical insulator with high dielectric strength, it resists heat, and it keeps its mechanical stiffness where unreinforced plastics would creep. The laminate structure also shows in the machining: the pale green woven texture visible on the finished part is the glass cloth, and cutting it cleanly takes diamond tooling rather than carbide.

The geometry is demanding. The part runs 204.82 mm overall, from a 25.0 mm diameter flanged head down a tapered transition to an 11.13 mm slender barrel that runs about 180 mm. The wall of that barrel is roughly 2.3 mm. A 6.48 mm bore runs through the full length, which at this aspect ratio is a deep hole drilling job: drills wander and laminates tear, so the bore is piloted, peck fed and gauge-verified over its full length with a long pin gauge.

Turning the slender barrel is the other discipline. At 2.3 mm wall the tube deflects under cutting pressure, and deflection reads directly as coaxiality error between bore and outside diameter. The tube is turned between centers with steady and follower rest support, using PCD diamond tooling at controlled speed so the glass fibers shear instead of lifting. Coaxiality of the finished tube is held within 0.05 mm and every part is verified on the CMM.

The flanged head carries a 45 degree spaced pattern of 3.28 mm through holes, two 6.17 mm cross locking holes and two 6.35 mm radial holes, all drilled and CMM checked for position. Fibrous materials leave fuzzy edges where ordinary metals leave burrs, so edges are deburred with fine diamond tooling, then the parts are ultrasonically cleaned and dried to pull machining dust out of the woven surface before inspection.