Small Projects #28: Dual Bowl Twin Screw II

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Blog entry by Madmark2 posted 04-24-2020 08:20 PM 229 reads 0 times favorited 0 comments Add to Favorites Watch
« Part 27: Twin Screw Lidded Purpleheart Pipe Design Part 28 of Small Projects series Part 29: Insulating the Garage Door »

The prototype being successful I made five more pipes, one with a special dual bowl design.

Five pipes, one with a secret surprise!

Starting with a board we progress to functioning pipe blanks.

  1. Lovely purpleheart is a full 1” thick
  2. The purpleheart was ripped at 3/4” and then recut to 3/4” leaving a 5/32” offcut with a TK blade. The 24” piece was cut at 3-7/8” and yielded six pipe blocks with about 1/4” left over. Talk about 100% yield!
  3. The paired pieces are taped for alignment
  4. The through screw holes are piloted for 6-32
  5. Tapping the holes is easy with the VSR cordless drill. Lubing with Johnson’s paste floor wax makes the tap cut easily. I run the tap to full depth twice, once to cut, once to clean.

  1. The screw holes are tapped and the bowl drilled in two steps. Note the one pipe with TWO bowls! One for now, one for later!
  2. The magnetic square and crude fence work surprisingly well to align the stem drill. The clamp holds things tight so both hands are free to work the drill press and air hose.
  3. The stems are longer than the drill press stroke so the last bit has to be drilled by hand with an aircraft drill. The pink zip tie serves as an adjustable stop to prevent over drilling.
  4. A Jorgensen clamp gives huge clamping pressure over a large area but releases with a quarter turn. The Incra fence locks in two places and gives a rock solid clamping surface.
  5. At this point we have five functional pipe blanks ready for shaping.

Shaping is the real creative part. Up to now the blanks are identical. The bandsaw forms the basic form and the sander allows the creative juices to flow. I generally don’t know the final form until I create it.

Resuming the manufacturing process:

  1. The blanks are paired with their lids and tightened down
  2. The basic form is cut on the band saw
  3. Coarse (80 grit) sanding on the oscillating belt sander creates the near-final form
  4. Fine (240 grit) sanding with an ROS cleans up the form and smooths the finish.
  5. Disassembled and slathered with two coats of wax.
  6. Finished and ready for packaging.

Only four made it to packaging, the two holer is mine!

Although the color seems all over the board it will rapidly darken to a uniform deep purple.

-- The hump with the stump and the pump!

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