Machining Two introductory projects 1.Support post for mirror mount 2.Vertical micro-rail mount

Certification Required by TAMU Complete course at –submit printout of completed exam

General machine shop skills Safety is first Always follow shop rules Never reach toward moving machine part or tool Rehearse procedure before turning machine on Anticipate hazards Never rush a machine – machining should be relaxing Machines to learn how to use Band saw Lathe Drill press Mill Measurements Optics table – metric, Machine shop – inches Fractional inches Binary but expressed as reduced fractions (ex: 1/4, 5/64) –Hard to tell which is larger Thousandths of an inch = mils

First pieces to make Mirror mount post -- round Lens mount post =-- square

Project 1 – Mounting post Start with round stock ~ 1-1/2 inch diameter Cut longer than desired length on band saw Band saw safety & care –Set blade guard as low as possible –For round stock – hold in vise –Keep piece in contact with saw table –Fingers away from blade – push stick ? –Lubricate blade –Ease up pressure near end of cut –Listen for bumping sound – metal caught in blade teeth Face off one side on lathe –Make end face perpendicular to cylinder axis –Triangular tool mounted in tool holder Lathe safety –Spin work once by hand after every change in setup –Keep hand on power switch when starting first time –Stand clear of rotating piece – pieces can fly off Face off other side Shorten by removing material Mounting post Band saw rough cut Measure and face off

Lathe Round pieces –Work piece moves –tool is stationary

Mounting post – part 2 After face off – machine recess Insures broad area contact on mount assembly –Alternative – grind mating parts on optical flat Press tool into face with lathe spinning Take off ~ 40 mils, up to half diameter of piece Start screw hole with center drill More rigid than ordinary drill Insures hole is in center Finish screw hole with number drill Number keyed to intended thread size Ex: #7 drill for ¼-20 threads Drilling procedure Lubricate and drill 1 st half inch When metal chips slow down – remove, clean, lubricate Repeat more often as hole gets deeper Cut recess Recess (dimple) End view With recess No recess Ring of contact points Single contact point Center drill

Tapping Cut screw thread – special tool = tap Usually final operation Most difficult (least dangerous) Broken taps common Many tap extraction tools – rarely work Usually must start over How to save tap 1. Treat like piece of glass of same size and shape 2. Use special tap lubricant – some dissolve aluminum 3. Use tap guide to start – tap must be aligned along hole axis 4. Frequently back tap out 1 turn – especially when deep 5. Choose tap holder –Long holder gives better control over torque –But easy to give too much torque Piece Tap guide Prevent bending motion Tap holder Long tap holder

Project 2 – Micro-rail vertical mount Start with 1-inch square stock Cut in band saw Square off ends in mill Also machine recess grooves on ends if necessary Milling machine safety Mount work securely Don’t take off too much on one pass Drill holes in one end and two along one side Side holes must be spaced by whole inches Must be precise Measure, mark, punch, then drill Punch makes small dimple – guides drill bit Drill press safety Hold work in vise Ease up pressure before going through Punch Hit with hammer Tip makes dimple Workpiece

Mill Square pieces –tool moves

Drill press Drill holes

Safety review 1. Always wear safety glasses 2. Never reach toward or point at moving parts of machines 3. Lathe –Mount workpiece and tool tightly –Spin chuck once by hand just before starting 4. Mill –Mount workpiece tightly –Make translation stages stiff 5. Drill press –Use vise for small work pieces 6. Band saw –Keep hands far from blade