Orbital Welding Collets for Arc Machines Weld heads (clamp inserts) are made to the highest quality standards. All our collets are made from stainless steel to give you better wear over aluminum type collets.  Our new spring design collet will hold oversize, undersized tubing and new or used collet adapters better than ever. Our new spring collets have more flexibility to hold all types of tubing or pipe. Our 500 heads now offer gate screws with springs to hold the latch up to make closing the upper gate easier. Our one-piece construction on the lower head will give you better alignment on both sides of your tubing.