8mm socket wrench or posi screwdriver (Dependent upon machine age)
Brush/cloth for cleaning
Silicon spray lubricant
What to do
Using the 8mm socket wrench or posi screwdriver remove the two screws securing one of the cutter bar end plates.
Remove the old cutting head.
Take this opportunity to clean the cutter bar with a cloth moistened in diluted detergent then buffed dry with a dry cloth. Lubricate the two v shaped bearing grooves with silicon spray lubricant being careful not to get overspray on other parts of the machine or worktable. Protective mask and gloves should be worn
Slide the cutting head onto the end of the cutter bar being very careful not to damage the plastic bearing blocks on the sharp/pointed edges of the cutter bar.
Replace the end plate. Adjust the sliding bearing blocks as follows:
Tighten the outer two adjusting screws to lock slideblock in place and bed the screws into the blocks.
Turn each adjustment screw anti-clockwise two full turns and the cutting head should slide loosely, if not undo both screws another half-turn until it does.
To adjust the bearings, place the long end of the 2mm Allen (hex) key into either one of the outer screws and very gradually tighten it with one hand whilst moving the cutting head up and down the cutter bar with the other.
Once you feel the sliding motion start to tighten undo the screw the smallest amount possible so the cutting head just slides easily.
Repeat this on the other screw, further finer adjustment on each screw may be needed to achieve an easy sliding movement with zero side play.