This gave us a support on which the 10 foot length of Pyrex glass could he joined and a means of variable speed rotation at a minimum of cost, The chucks were designed and built in the Chemistry Department Instrument Shop, and an overhead chain hoist was installed in a sub basement area providing plenty of floor and overhead space.
				Figure 1
	It was decided to seal the 4 foot length to the 2 foot section, then to remove this assembly from the lathe, to anneal it, then rechuck it prior to sealing to the remaining four-foot section. As the 6 foot length of tubing was quite light, two men could handle it easily in the chucking operations. Prior to the sealing operations, a preheat cycle of two to three hours was used, gradually increasing air flow to the two Litton hand annealing burners until a good strong bushy flame burned off the carbon layer deposited in the early stages of heating. A reversal of the preheating cycle was used to cool the tube down to room temperature after the sealing operations. Sealing the 18 inch tubes was accomplished with two Litton 10 fire 7 jet Lathe burners, set vertically on a movable cart, surrounding the 18 inch tube except at top and bottom. Each burner was fed with its own oxygen and hydrogen cylinder. A spare cylinder of hydrogen and oxygen was T'd in to each burner, In the event the original supply ran out. With this method supply, we were assured 20 minutes of maximum heat per burner. (See Figure 2). While induction heating would have been the optimum sealing method, the requirement for only two seals and the financial constraints, dictated the choice of oxygen and hydrogen heating. This method of heating proved satisfactory on tubing of this size.
								Figure 2
	MOVEABLE CHUCK DETAILS In order to close the space between the heated ends of the 18-inch tube, a movable chuck, working through the center of the central pipe was designed. Two rings of 6 inch I.D. by 7 inch O.D. by 3 inch long steel tubing were used as sliding surfaces and supports for chuck jaws. A lateral motion was transmitted by a hand crank wheel at the extreme end of the 6 inch ripe, rotating a threaded shaft, engaging a lever connected to one of the sliding rings in the chuck. An in and out motion can he transmitted to the entire chuck, and the tubing on the chuck as well in this manner.
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