User:DrRob/Belt anchors

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Revision as of 15:34, 27 March 2012 by DrRob (Talk | contribs) (fix typo)

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Parts list

Per belt anchor, so x4 for each ShapeOko:

  • 3x M5 x 8mm bolts
  • 3x M5 washers
  • 1x M5 nut
  • ~50mm length of aluminium right-angle section, sides ~10-12mm
  • 1/4" x 3/4" x 2-1/2" steel strip with two holes, supplied with the ShapeOko kit

Tools required

  • Drill
  • 4.5mm drill bit
  • 5mm drill bit
  • 5mm thread tap
  • hacksaw or jigsaw to cut the aluminium

How to make them

  1. Cut two ~25mm lengths of aluminium right-angle section
    • Actually the top piece doesn't need to be right-angle section - you can use a flat strip of a similar width instead
  2. Hold one piece against the steel strip as shown in diagram 1 below, so that the tops are flush, and mark the position of the hole with a pencil
  3. Centre-punch the centre of the hole
  4. Drill through with a 5mm drill bit
  5. Now take the other piece of right-angle section, and centre punch roughly in the centre of the left-most third, and the right-most third, as shown in diagram 2 below
  6. Clamp the two sections together as shown in diagram 3 below
  7. Drill through the unclamped side with a 4.5mm bit
  8. Tap the 4.5mm hole to 5mm
  9. Remove the clamp
  10. Drill out the hole in the top piece ONLY to 5mm, removing the thread
  11. Put the sections back together, and screw in one of the bolts to clamp them back together
  12. Repeat for the other side, as shown in Diagram 4
  13. Using a 5mm bolt, nut and washer, fit the bottom section to the steel strip
  14. Place the end of the belt across the top, between the two threaded holes, then loop it back on itself, teeth to teeth.
  15. Put the other section on top, and screw two bolts through into the lower section. Don't do it up tight yet.
  16. Using the loop of belt as a handle, pull the belt tight, using your precisely calibrated muscles to pull with 6lbs of tension, and while holding that tension, tighten the two bolts to clamp the belt in place.
    • Obviously you only need to apply the tension while doing the second side of each belt.