FIG. 1 SECTIONAL VIEW OF ATLAS 12" TIMKEN BEARING HEADSTOCK
(Necessary for replacing spindle belt or bearings) (Refer to Figure 1)
1. Disengage back gears.
2. Loosen set screw in collar B and remove collar by turning anti-clockwise. Beneath set screw is a small thread protector. Do not lose it when collar is removed.
3. Loosen set screws in collar L, and large spindle gear D.
4. Slide spindle gear M from spindle. If gear sticks, tap lightly with a piece of wood and a hammer.
5. Remove key N from spindle with a pair of pliers. Slide flanged collar O off spindle.
6. Wedge two pieces of wood between head and large spindle gear D on both sides of spindle.
7. Place a piece of wood against left end of spindle and drive it in direction indicated by arrow until key P emerges from large spindle gear D.
8. Remove the wood wedges and remove key P with pair of pliers.
9. Drive spindle entirely out of headstock in direction of arrow. BE SURE TO CATCH THE SPINDLE AS IT IS RELEASED FROM THE HEADSTOCK. It is not necessary to remove spindle entirely if replacing belt only on horizontal countershaft lathes.
(Necessary for replacing spindle belt on underneath drive lathes)
1. Remove headstock spindle.
2. Lower quadrant assembly.
3. Loosen and remove both screws in back gear lever clamps. (See Figure 2)
4. Drive out groove pin Q that holds back gear shaft to eccentric sleeve.
5. Loosen set screw in collar R and slide complete tumbler assembly and back gear shaft out of headstock in direction indicated by arrow.
6. Remove back gears and collar from headstock.
1. Lightly file all burrs from the back-gear shaft and eccentric.
2. Slide back gear shaft, with tumbler assembly, through left side of headstock, replacing collar R and back gears. Be sure belt is in position.
3. Remove cap S from headstock.
4. Slide back gear shaft in right hand eccentric sleeve T, turning sleeve with a screw driver to line up groove pin hole in sleeve and shaft.
5. Replace groove pin Q and slide collar R against headstock and tighten set screw.
6. Replace back gear lever clamps with screwdriver slot in original position of about 30
° from the vertical and back gear lever in the out position, tighten lever clamps.7. After reassembling the headstock spindle, run the lathe in back gear drive to check the mesh of the back gears. If lathe runs noisy, or if there's too much play between the gears, stop the motor and shift right eccentric sleeve -- see "Back Gear Adjustment."
1. Lightly file all burrs caused by set screws from spindle and keys N and P.
2. Clean all parts thoroughly, including Timken Bearings.
3. To reassemble, reverse the procedure in "Removing Headstock Spindle." Be sure belt is in position. When driving spindle into headstock, use the palm of your hand as much as possible to avoid damaging the precision surfaces of the spindle nose. Use Figure 1 as a guide, making sure all parts are installed in their proper positions. Read the following instructions for spindle and back gear adjustments.
1. Slide collar L against shoulder of spindle and lock in place. Move pulley-gear assembly against collar and slide large spindle gear D against pulley and tighten set screw in gear. There should be a slight amount of clearance between the pulley and the large spindle gear to permit pulley to turn freely.
2. Tighten collar B until all lateral (end) and radial (side) play has been removed from spindle. Check by tapping spindle back and forth with the hand. Do not tighten too tightly -- spindle should rotate freely.
3. Pre-load spindle bearings by continuing to tighten the threaded collar B approximately 1/16" turn (equivalent to two spindle gear teeth). There should be a slight drag felt as the spindle is rotated by hand. This is important because as spindle and bearings warm up, the spindle expands laterally approximately .002". Tighten set screw in collar B.
1. Shift back gear lever upward to the Out position.
2. Loosen back gear lever clamp screws -- see Figure 2.
3. Remove cap S in right end of headstock, and with a screwdriver turn the eccentric sleeve slightly. Tighten clamp screws, and check gear mesh by placing lever in back gear position.
4. Repeat adjustment, if necessary, until gears are in proper mesh.
The driving belt on the horizontal countershaft lathe is adjusted easily by means of the square head set screw in the countershaft arm. Make the adjustment with fine belt tension lever in the back position so that the center of the belt can be pushed in about one-half inch with a moderate amount of pressure. V-belts do not have to be tight in order to drive normal loads, and belt life will be lengthened by running them fairly loose.
The motor drive belt is adjusted by moving the motor bracket up or down. This adjustment should also be made with the belt tension lever in the back position -- a moderate amount of pressure should depress the center of the belt about one-half inch.
The spindle belts on the underneath drive lathe are adjusted by loosening the bracket mounting bolts and raising or lowering the drive shaft bracket. Adjust the tension on the belt between the four step pulleys on the spindle drive shaft and countershaft spindle by turning the tension adjusting nuts. Make this adjustment with the belt tension lever in the lowest position.
The motor drive belt is adjusted by moving the motor up or down on the mounting bracket. Adjust the belt with the tension lever in the lowest position.
