Sharp 1118H, Operations Manual & Parts List, Page: 22 / 68

20
Inch Threads Using Outside Chang Gear
1. Turn disconnect switch “OFF”.
2. On inch side of change gear bracket “D” (Figure 50), mount “First Gear on Stud” “C”
(Figure 50) with spacer between gears. Do not tighten bolt “A” (Figure 50) fully.
3. Mount “Idler Gear” “Y” (Figure 50) but do not mesh with “First Gear on Stud” “C” (Figure
50), or tighten bolt “Z” (Figure 50) fully.
4. Loosen knob “S” (Figure 48), open gearbox door and remove 50 tooth gear “S” (Figure
48), and 127 tooth gear “T” (Figure 48). Do not misplace key under 50 tooth gear.
5. If thread chart specifies number of teeth in “First Gear” to be other than 22 teeth,
remove gear “U” (Figure 49), and replace with specified gear.
6. Remove tumbler gear “W” (Figure 49).
7. Mount Change gear bracket assembly, Figure 48, on pivot post “V” (Figure 49). Do not
tighten bracket bolt “H” (Figure 51), fully.
8. Make certain key is in place and mount “Screw Gear” “J” (Figure 51). Replace bolts “K”
(Figure 51) and “M” (Figure 51).
9. Adjust “Second Gear on Stud” “G” (Figure 51), with 0.08 ″ -0.010 ″ backlash between it
and “Screw Gear” “J” (Figure 51). Use plastic shim stock to help determine backlash.
Tighten bolt “F” (Figure 51).
10. Adjust “Idler Gear” “E” (Figure 51) with 0.003
″
-0.004
″
backlash between it and “First
Gear on Stud” (behind “Second Gear on Stud” in picture). Tighten bolt “N” (Figure 51).
11. Pivot bracket to obtain 0.003
″
-0.004
″
backlash between “First Gear” “L” (Figure 51) and
“Idler Gear” “E” (Figure 51). tighter bracket bolt “H” (Figure 51).
12. Make certain all gears are properly meshed and all bolts tightened.
13. Close gearbox door, tighten knob “B” (Figure 46), and turn selector knob “C” (Figure 46)
to position specified on chart.
14. Turn Inch/Metric knob “D” (Figure 46) to Inch.
15. Turn Feed/Thread knob “E” (Figure 46) to “Thread”.
16. Follow same procedures for setting carriage stops lead screw nut and compound slide
as when cutting threads form the gearbox. Use of carriage control level “G” (Figure 46),
and quick-acting handle “P” (Figure 47), will also be the same as when cutting threads
from the gearbox.
NOTE
： ： ： ：
(a) 50 tooth gear “S” (Figure 48), and 127 tooth gear “T” (Figure
48) must be remounted (without bracket) to obtain metric
thread pitches through gearbox.
(b) When disassembling setup, remount 22 tooth gears “U”
(Figure 49) and “W” (Figure 49).