Adjusting Gibs
Gibs are tapered lengths of metal sandwiched between two moving surfaces to control how much friction they have when they slide past one another. Correctly adjusting the gibs is critical to producing accurate milling results.
Tight gibs make table movement more accurate but stiff. Loose gibs make table movement sloppy but easy. The goal of gib adjustment is to remove unnecessary sloppiness without causing the ways to bind.
Tip: Many experienced machinists adjust the gibs until there is just a slight drag in table movement.
Screws on each end allow gib adjustment to increase or decrease the friction between the slid- ing surfaces of the ways.
DISCONNECT MACHINE FROM POWER BEFORE ADJUSTING THE GIBS!
Make sure all table locks are loose. Then, loosen one gib adjustment screw (see Figure 44) and tighten the opposing screw the same amount to move the gib, while at the same time using the handwheels to move the table until you feel a slight drag in that path of movement.
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Figure 44. Location of gib screws.
Adjusting Leadscrew
Backlash
Leadscrew backlash is the amount of
Leadscrews must have a certain amount of back- lash, but over time, this will increase with normal wear. Generally,
The X- and
The
Cap Screw
