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SSA Tower Rework Instructions(for composite sleeve bearings)

F. Kamphues

SSA Tower rework

Reason: Implementation of composite sleeve bearings for the Tower Locks

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Scope of Work

Required modifications in accordance with drawing M1S-100-01301 Prototype V3 Rework Composite Brg REV A– Tower M1S-100-01301:

Tower Lock holes to be increased from 22 to 27 mm

Drill, tap and install M4 helicoil in each “ear” for end stop

Install GGB 222718GF sleeve bearings (press fit)

Drill and tap through side of sleeve bearing (for Spring Plunger) 3X 1/2-13 UNC-2B THROUGH TO BORE, BACK SIDE CHAMFER 2.00 X 45

– Lock Assembly M1S-100-01400:

Deburr edges of spring plunger detents

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Scope of Work

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M1S-100-01301 Prototype V3 Rework Composite Brg REV A:

TMT furnished equipment

TMT provides GGB 222718GF sleeve bearings

TMT provides 1/2-13 UNC-2B Delrin Spring Plungers

TMT provides Machining Fixture– With registration pins and datum surface for accurate location of Tower– A setup for bearing holes and M4 helicoil hole machining– B setup for drilling & tapping spring plunger holes

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A B

TMT Machining Fixture

Machining Fixture (arrow side is datum)

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Preparation of Towers

Anodize Tower in accordance with drawing

Install Registration Inserts M1S-100-01304

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Installation Procedure Setup A - 1/5

Installing brass registration pins in Machining Fixture (location A)

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Installation Procedure Setup A - 2/5

Install and Align Machining Fixture on CNC machine. Arrow side is datum and should be perpendicular to machining axis.

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Installation Procedure Setup A - 3/5

Install Tower on brass registration pins.

Install clamps

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Installation Procedure Setup A - 4/5

Install anti-chatter support (with very light preload to prevent deformation in the clamped state!).– Support is not provided by TMT (use a threaded rod with two nuts, or

similar)

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Installation Procedure Setup A - 5/5

Check alignment and CNC software before starting machining!

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Machining Setup A

Machine holes to 27.000 – 27.021 mm

Drill and tap for M4 helicoil

Repeat for other two “ears” (rotate 120°, 240°)

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Install sleeve bearings

Press fit sleeve bearings (3x) in accordance with GGB Composite Bearing Handbook section 6.1– Bearings shall be installed 0.2 - 0.5 mm deeper than flange (to

accommodate lock barrel radius)

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Fit check lock barrels

Fit check lock barrels (bearing does not require lubricant)

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Installation Procedure Setup B - 1/3

Move brass registration pins from location A to B)

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Installation Procedure Setup B - 2/3

Install Tower on brass registration pins.

Install clamp

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Installation Procedure Setup A - 3/3

Check alignment and CNC software before starting machining!

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Machining Setup B

Drill and tap for Spring Plunger– Carbide drills should be used for drilling GGB filament wound bearings.

To avoid fiber breakout, use a mandrel to support the ID.

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Machining Setup B

Apply backside chamfer in tapped hole (may be done by hand; chamfer size is not critical)

Repeat for other two “ears” (rotate 120°, 240°)

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Fit check Spring Plunger

Fit check Spring Plungers (should be able to go all the way through)

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Deburring Spring Plunger Detents

Hand deburr detent edges with round grinding wheel and fine Emery cloth. Edges shall be round and smooth!

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