Makerbot Replicator 2 (and 2X) : Tightening Belts

Symptom of loose belts 

Slanting Nut from loose belts

Slanting of print (I.e. a straight wall it 45 degrees). In extreme cases belts slipping on the pulley Both the photos right are caused by a loose belt. 

Note : the slanting nut can also be caused by a slight miss alignment of the gantry also. Quicj check for this is to slide the gantry all the way forward and then look upwards through the front window to the two front corners. The plastic gantry mount should have tapped the rod mount attached to the chassis. Even a 2mm gap can cause skewed prints. If this is your problem you will have to re-align it.

How often do you need to tighten them

We have found it is a good idea to check these when you have moved the machine, or every 700-1000 hours

How do your tighten them : 

a) X Axis

There is adjustments for the X Axis at the right hand side of the gantry. You will find 4 screws on the stepper motor mount (facing the back of the machine).

TIP 1: Unscrew the side ornamental face for easier access (especially if you have windows fitted)

TIP 2 : find a friend, it is much easier with 2 people

Loosen all four screws (do not remove them but loosen them so the stepper motor can move left and right in the adjustments. Person 1 pull the motor to tension and Person 2 tighten the screws again.

b) Y axis

Similar set up on Y axis (small belt at the back of the machine), but easier so it can be done with one person

How tight should it be ? 

Firm but it does not have to be super tight. A nice twang instead of a thud when you pluck it. Defiantly not drooping!

Check your belts

It is good practice to check the belts for damage like worn teeth, at the same time as tightening the belt. A damaged belt can cause the same symptoms as a loose belt and even a damaged motor cable.