MIL-HDBK-660 Fabrication Of Rigid Waveguide Assemblies Sweep Bends And TwistsThis handbook is intended for the electronic installations technician to be used as a guide for fabricating rectangular waveguide bends and twists used in the microwave region of the electronic spectrum.

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MIL-HDBK-660B

CONTENTS - Continued.

SECTION Page

4.4.1.6	Twisting and bending ...............................................................................................................	15
4.4.1.7	Mandrel material and finish ......................................................................................................	15
4.4.1.8	Polytetrafluoroethylene mandrel...............................................................................................	15
4.4.2	Wallance bending machine ......................................................................................................	16
4.4.3	Hydraulic push press and portable hydraulic bender method ..................................................	19
4.4.4	Hand bending machine.............................................................................................................	21
4.4.5	Bench vise................................................................................................................................	22
4.5	Twisting of the waveguide ........................................................................................................	22

5. DETAILED REQUIRMENTS (PRE-ASSEMBLY, ASSEMBLY, FINISHING OPERATIONS) 25

5.1 Removal of filling............................................................................................................................	25
5.1.1 Alloy method..................................................................................................................................	25
5.1.2 Rosin method.................................................................................................................................	25
5.2 Removal of dents and wrinkles from waveguide............................................................................	26
5.3 Cutting ...........................................................................................................................................	26
5.3.1 Hacksaw ........................................................................................................................................	26
5.3.2 Power saw .....................................................................................................................................	26
5.3.3 Squareness of cut..........................................................................................................................	26
5.3.4 Modification of flanges and heavy wall waveguides for proper fit ..................................................	26
5.3.4.1 Cover flange .............................................................................................................................	26
5.3.4.2 Choke flange ............................................................................................................................	27
5.4 Cleaning.........................................................................................................................................	28
5.5 Attachment of flanges ....................................................................................................................	28
5.5.1 Assembly of contact or cover flange to waveguide ........................................................................	28
5.5.2 Assembly of choke or socket flanges to waveguide.......................................................................	29
5.5.3 Clamps and jigs .............................................................................................................................	30
5.6 Silver brazing brass waveguide .....................................................................................................	30
5.7 Brazing flanges on aluminum waveguide.......................................................................................	35
5.7.1 Torch tips .......................................................................................................................................	36
5.7.2 Brazing rod ....................................................................................................................................	36
5.8 Dip brazing aluminum waveguide ..................................................................................................	36
5.8.1 Brazing flux ....................................................................................................................................	36
5.8.1.2 Preparation of parts..................................................................................................................	36
5.8.1.2.1 Cleaning ...................................................................................................................................	36
5.8.1.2.2 Chemical dipping......................................................................................................................	36
5.8.2 Assembly .......................................................................................................................................	37
5.8.2.1 Final cleaning ...........................................................................................................................	37
5.9 Dry air piping connections..............................................................................................................	37
5.9.1 Air connection completion..............................................................................................................	37
5.10 Finishing operation.........................................................................................................................	37
5.10.1 Finishing operation.........................................................................................................................	37
5.10.1.1 Machining .................................................................................................................................	37
5.10.1.2 Smoothing ................................................................................................................................	37
5.10.2 Cleaning waveguide ................................................................................................................	37