2.1. MyoBone ‘Parallel Assemblies’ - Four Round Tube Fibres

2.1.1. Prepare parts Step 1: Cut fibres to the desired length



  • Lathe can create a precise cut and avoids damaging the tube Step 2: Mill the tube ends


Mill the inside hole of both tube ends in order to create a rough surface for gluing.


  • Use a round moulding cutter with an automatic screwdriver
  • Use gloves to protect you from dust Step 3: Positioning of the tube length


Insert the tubes in the tube holding-support and position the tubes with the distance support. Fix the tubes with the screws. Step 4: Gluing threaded pin in tube ends


Add glue evenly to the threaded pin and hole. Use the distances according to the MYO-Bone class.


  • While drying, use a fixture to keep the thread pin and fibre centred and at the correct distance
  • Wear protective gloves Step 5: Remove the leftover glue


Remove the glue with a cutter knife. Consider the hardening-time of the glue.

Production of spacers Step 1: Water-jet


Order water-jet cut part shape (aluminium). Step 2: Drilling and threading of holes


Drill and thread the holes of the flexure clamps.


  • Put small fibers in the flexure clamps to avoid deformation caused by the pressure exerted by the drill bit Production of end plates and flanges


End Spacer:

  • Selective Laser Sintering (Polyamide)

SB Flange plate:

  • Machining (Aluminium)
  • Selective Laser Sintering (Polyamide)

Screws, nuts and washers are standard parts.

2.1.2. Assembly


Material needed

4 x CFRP tubes with threaded ends

4 x spacers

16 x M2.5x10 countersunk head screw (DIN 965)

2 x end spacer

8 x M4 thin nut (DIN 39)

8 x M4 spring washer (DIN 127)

2 x SB flange plates

8 x M3x25 countersunk head screw (DIN 7991)

8 x M3 thin nut (DIN 39)

8 x M3 spring washer (DIN 6798) Step 1: Assemble fibres and spacers


Slide the fibres (1) in the flexure clamps (2) of the spacers.


  • Slide one fibre through all spacers, and then go on with the next fibre
  • Flexure clamp screws should be loose
  • In preparation for the next step, regroup the spacers next to each other Step 2: Plug fibres in the end-spacer


Plug each fibre in one of the holes of the end-spacer.


  • Apply sufficient pressure so that the end of the cfc tube is in contact with the shoulder at the bottom of the hole
  • Do not press the fibers firmly into the holes Step 3: Screw fibres to the end spacer


Screw each of the fibers to the end-spacer using the M4 nuts and the large spring washers.


  • Screw the nut until the spring washer is nearly flat, not more
  • (if you screw further, you may pull the threaded pin out of the tube) Step 4: Attach the other end-spacer


Repeat steps 2 & 3 for the other end-spacer.


  • Make sure the end-spacers are as much as possible:
  • Parallel to each other
  • Perpendicular to the fibres
  • Lay the bone on the table to ensure that it is not twisted Step 5: Adjust the spacers


Arrange the spacers equidistantly between the two end-spacers.


  • Distance between spacers: 51 to 52 mm
  • Ensure that the spacers are perpendicular to the fibres Step 6: Check straightness


Check that the MYO-Bone is straight and that both end-spacers are parallel to each other.

If necessary proceed to adjustments. Step 7: Attach the SB flange plates


Screw the SB flange plates to the end-spacers with the M3 screws.

Use the small spring washers together with the M3 nuts (backside).