Material: Al 6061

Failure Modes: 

  • Deforms from piston force

Purpose:

  • Tapped hole through center for piston connection

  • Eight tapped radial holes for interface with booster cup

  • Four tapped holes for AV Bay rods

  • Pie cuts for mass reduction

Stock Dimensions:

  • Thickness = 0.4 in

  • Length = 2.25 * diameter of mount = 2.25 * 4 = 9.0in

  • Width = 2.25 * diameter of mount = 9.0in

  • Length and width = about 14 in by 14 in

Manufacturing Plan:

Extra notes before machining:

  • Note: The CAD for the rope guide from McMaster is not exact- wait for the physical part to arrive, check hole dimensions, and machine carefully

  • Check the waterjet thickness again!!!

  • If you think you’re done tapping, keep going more.

  • Do not tap fast otherwise taps will break.

  • Use a lot of tap oil.

  • Double check spindle speed for all operations.

  • Double check tap size

Step 1 - Waterjet top face profile:

  1. Lower size of holes on the top face by 0.005” to account for tolerance of waterjet before 

  2. Use Quality 3

  3. 2 tabs of width and height 0.1”

  4. Set thickness to 0.4in

  5. Set Material Al 6061

  6. Ensure mass-saving cuts do not interfere with waterjet nozzle. If they do, pause the waterjet and remove the mass-saving cuts.

Step 2 - Turn down part on Lathe:

  1. Use a cylindrical support rod to hold the piston mount in the lathe for turning operations.

  2. Zero x and z offset on lathe to the edge of the diaphragm.

  3. Set the go-to of the x axis as the measured diameter of the part.

  4. Set the go-to of the z axis as the measured thickness of the stock minus the lip length needed.

  5. Turn in 0.02in increments (more if you’re an expert) along the z axis until the diameter gets about 0.015in away from the required diameter (4 in). Then, turn down in increments of 0.005 in.

Step 3 - Tap center hole with Mill:

  1. Clamp piston mount in vise

  2. Insert center drill bit into chuck

  3. Set spindle speed to 1200 RPM

  4. Drill initial hole and

  5. Replace drill tip with 5-8/18 hand tap

  6. Use tap fluid liberally while tapping

  7. Hand-tapping: turn 1 cycle and then turn back half a cycle. If you feel resistance, turn backwards to remove excess material

  8. Continue tapping until the tap is visible on the other side

Step 4 - Tap rod holes with Mill:

  1. Follow same process as above for each rod hole using a 1/4-20 tap

Step 5 - Radial Indexing:

  1. Properly set up radial indexer, ensuring sides are straight.

  2. Use a cylindrical support rod to hold the piston mount in the radial indexer for drilling operations.

  3. Check that the first centered hole is aligned so that no holes will be drilled into the spokes.

  4. Attach the center drill tip and align the drill tip at the correct distance in order to mark the center holes.

  5. Set the spindle speed to 1200 RPM.

  6. After drilling the first center hole, rotate the part by 45 degrees and continue drilling center holes (8 in total)

  7. Replace center drill tip with appropriate drill tip size intended for 8-32 tapped hole and drill through all center-marked holes

  8. Use a tap-handle and center to tap holes with 8-32 tap on radial indexer (Refer to tapping holes section for tapping instructions)

 

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