Take the pick up tube and insert it to the lower bearing as shown. Between the bearings, insert the following in the this order: M8 nylon washer; 36 teeth pulley (note the orientation); 60 teeth belt loop; SCCN8-6 collar, M8 nylon washer; spring; M8 nylon washer:
- Pick-up tube
- M8 nylon washer x 3
- GT2-36 pulley
- GT2-60 belt loop
- SCCN8-6 collar x 1
Tighten the pulley screws to hold the tube in place so, that there is still 10mm or so free movement left, before the low bearing and the Luer lock would hit. Rotate and slide the tube in the bearings and adjust the top bearing so, that the movement is smooth and free. Tighten the middle plate and the bracket in place and once more, check that the tube rotates freely and can easily move up and down.
Push the SCCN8-6 collar up and attach that to the tube so, that the spring just slightly pushes the tube down.
Slide the 16 teeth pulley to the motor shaft, base down. Slide the motor towards the tube so that you can get the belt in place. Pull the motor back tightening the belt slightly. Find a compromise where the belt is somewhat tight, and there is no slack in the bearings against the belt. (There is still some slack in the bearings sideways; we’ll deal with this later.) The tube should still move freely up and down. Tighten the motor in place. Rotate the tube a few times to allow the small pulley to find the correct height and tighten the pulley to the motor shaft.
You want the tube to be firm, easlily rotated and needing only slight force to move up a few mm’s.
Here is a customer supplied photo of this stage (thank you!):