Hadley 114 Telescope; Art's Remix

Remix of the Hadley 114 Telescope using 1/2" EMT conduit (cheap!) instead of 1/2" tube (expensive!)
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updated November 29, 2022

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Maff made something great with the Hadley.  I can never leave anything alone, even if it's great to start with, so here is a remixed version using ½" EMT conduit instead of ½" round tube.  I found that the ½" tube required to build the original Hadley was approximately $36-$40 from my local hardware store.  Being a cheapskate, I immediately tried to find a less expensive alternate, and found ½" EMT (galv steel, metallic) conduit in the electrical aisle for $7 for a 10-foot section.  Requiring 3X 3-foot pieces, this leaves me with plenty of material while reducing the overall budget by about $30 (if you already have a pipe cutter or know somebody that does).  This reduces the total build cost from about $150 to around $120 (plus plastic, printer time, and if you are ambitious, paint).

This version maintains the #10 English hardware requirement of the original version so I could continue to buy hardware at my local US hardware store.  I used 10-32 because I like fine threads better than coarse, but use whichever you want.

Here is a list of changes to the original:

  • Removed text (sorry I'm not so flashy)
  • ½" EMT (metallic) conduit used for tubes (approximately 18mm diameter)
  • Reworked focusing mechanism to use friction clamps instead of grub screws (didn't like the idea of damaging threads or shiny chrome bits by grubbing a screw into them)
    • Now requires some support, but not terrible to remove if you know how to add support blockers
    • Only part besides knobs that requires support
    • Can be replaced by any current remixes (compatible with original Hadley)
  • Secondary mirror mounting reconfigured
  • Mirror collimation hardware changed to Nylock nuts to maintain settings “better”
    • This required new spiders :(
    • I don't understand the point of double-nutting in the original.  This just means things have to be extra loose
    • Primary mirror holder got slightly thicker
    • Added caps over the nuts on the primary mirror holder in case of overtightening so the screws will not grub into the glass mirror/potentially chip glass.
  • Secondary mirror holder redesigned to have holes for collimation screws to seat/prevent rotation of the holder.
  • Redesigned baffle to be B-E-E-F-Y
    • Also a quick-release version for some reason
  • All wall thicknesses optimized for 0.4mm nozzle (attempted to keep thicknesses at a multiple of 0.4 to reduce “thin wall” defects
  • Slight tweaks to Upper and Lower Rings to remove extra walls/geometry that can contribute to print defects from cross-sectional thickness changes
    • Upper ring had some weird internal surface features and artifacts
    • Lower ring had diameter changes for some reason that I deemed pointless and removed
  • Clocked Lower Ring collimation screws to be 60 degrees offset from tubes to allow mounting of feet AND adjustment knobs at the same time
  • Included the following items remixed from other sources:
    • Cheshire collimator
    • Tube Feet
    • Primary and Secondary Covers
    • Primary Mirror collimation mask
  • Rocker box mounting hoops are full rings (not half-rings) and the wrap-around features have been removed.  Just print 2 and screw together and you should be good to go (removed left/right geometry features so it's the same part twice)
    • Also removed the countersink chamfers in order to use button head socket cap screws since the rest of the build uses those.  Needs at least 1" length screws.
  • My primary collimation knobs are glue-together design.  IDK.  I liked how they look without a hole in the side.
    • Only part besides one of the focusing pieces that requires support)

Things that are compatible with original Hadley:

  • Focusing assembly has same mounting size and pattern.  You can replace my assembly with any available for the original (if you want to avoid supports for example)
  • Original spiders and secondary holder should fit into new upper ring if you don't like how mine works.  Might require a slight touch of sandpaper on the spider, but “should” fit.
  • Mounting ring and hoops are the same extent dimensions of the original so should fit into similar rocker boxes.  Eventually I'll put one in this remix as well (made with ½" EMT of course).

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