A long thin screwdriver, unfolded paperclip or similar long thin implement
Cleaning cloths (one dry & one moistened in diluted detergent)
Silicon spray lubricant
Protective mask and gloves
What to do
Remove the blade holder, remove the sliding bearing blocks by taking out all four fixing /adjustment screws from the user side of the slideblock with the 2mm Allen (hex) key.
Push out the near bearing block from one end using a long thin screwdriver, unfolded paperclip or similar long thin implement.
Move the slideblock away and lift the cutting head from the cutter bar.
Remove the two fixing screws for the rear bearing block and replace with new, take care not to overtighten the replacement screws.
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
Reposition the slideblock and slide in the two near bearing blocks and fix in place with new screws.
Tighten the outer two adjusting screws to lock slideblock in place and bed screws into 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.
Refit the blade holder using new clamping knobs and replace self-adhesive bumpers if required.