Smithy Midas 1220 XL - Manual (Page 31)

To tighten the lathe belts, move the tensioner handle above the motor (Figure 5.5) so it
points toward the lathe head. Turn the knurled knob clockwise to tighten the belt and
counter clockwise to loosen it. If there is not enough adjustment, remove the pivot pin
and turn the knob as needed. Then reattach the pin.
Adjusting the Gibs
The Midas 1220 XL has straight gibs. Before using the machine, adjust the gibs to
compensate for wear and maintain the proper fit between sliding surfaces. Gib
adjustment affects cutting tool rigidity and the machine's ability to make accurate cuts.
As the gibs tighten, the effort it takes to turn the handwheels increases. Adjust the gibs
according to the work you are doing and personal preference. What's important is to
adjust them evenly. The tighter the gib, the more accurate it will be. Removing and
polishing the gibs also improves the tolerances.
Before beginning, make sure the ways are clean and well-oiled. You must also understand
locks for the compound, cross slide, carriage, and tailstock act directly on the gibs for
their locking power. Back these locks off completely.
Cross-slide gib. Start adjusting the cross-slide gib with the table centered on the
carriage. Back off all setscrews and jam nuts. Tighten the two inside setscrews all the
way (Figure 5.3), locking up cross-slide movement. Then back off each setscrew
one-quarter turn and check the movement. Finally, set the tension on the outer screws
to match.
The effort it takes to move the table should be the same in both directions. if it is not,
the gib is not adjusted evenly. If you feel more handwheel resistance when the cross slide
is going away from you, the leading edge of the gib is too tight. Back off the setscrew
closest to you a little to relieve the tension. If there is more resistance when the table is
coming toward you, the leading edge of the gib is too tight, and you should adjust the
screw furthest from you. When everything is set, hold the setscrews carefully with the
Allen key and lock the jam nuts.
Carriage gib. The carriage has only two gib-adjusting screws, accessed through holes
in the front of the apron (Figure 5.1). Start the adjustments as you did with the cross
slide: tighten the screws all the way, then back them off one-quarter turn and test the
setting. Handwheel resistance should be even in both directions.
The big difference between the cross slide and carriage is that the carriage gib travels
with the carriage as it moves down the lathe bed. If you have more handwheel resistance
when the carriage moves toward the tailstock, the leading edge of the gib is on the right
side of the carriage, the same side as the direction you are moving the carriage. If you
have more handwheel resistance when the carriage is moving toward the headstock, to
left, release the tension a bit on the left-hand gib setscrew. As you work with the
adjustments, you'll feel the difference even gib tension makes on the handwheels.
Compound gib. The compound gib has two adjusting screws and jam nuts (Figure 5.3).
For greater tool rigidity, you can adjust the compound gib a bit tighter that the others.
6-10 Or Visit www.smithy.com
Uncrating and Setting Up the MI-1220 XL