TRUCK SERVICE MANUAL
ENGINE
(ST-1177-16), Fig. 1-16, through centering rings rotating
5. Align tool bit hole in cutter holder with hole through
slowly. Bar should spin free. Slide bar out one end until
micrometer base shaft and tighten cutter holder socket head
appropriate checking ring can be installed in bar. Oil outside
screws. Scribed lines are used on the base shaft and cutter
diameter of checking ring.
holder for this purpose. Keep even gaps between two halves
of cutter holder.
5. Using light finger pressure against checking ring (ST-
6. Insert appropriate cutting bit in tool holder. Tool must
be short enough so it does not extend into the bore of the tool
1177-13) on both sides of bar, push checking ring through
holder. When adjusting micrometer or tool cutter, be careful to
each bore. Bar must be turned during this check.
"just contact" tool to prevent damage.
a. Check bore for burrs if checking ring will not pass
7. With cutter key (ST-1177-49) adjust tool bit against
through bore.
micrometer spindle and tighten tool bit retaining screw in cutter
b. A 0.003 inch [0.08 mm] feeler gauge (not over 1/2 inch
holder, back off micrometer and check tool bit setting.
[12.70 mm] wide) can be used in detecting irregularities in the
Note: Do not tighten micrometer spindle against tool bit point
bore.
or carbide may be chipped. Do not sweep micrometer spindle
c. Attempt to insert feeler gauge between bore and bar or
across carbide cutter for it will chip cutting edge.
slip ring as used on ST-1177 Boring Tool. Run gauge
8. Back off micrometer and remove cutter holder from
completely around bar or slip ring on each side of bore.
micrometer base shaft.
Evaluate as follows:
CUTTING BORES
(1) Gauge does not enter at any point, bar rotates freely std.
bore.
1. Install bore feed assembly (ST-1177-17) in one end of
boring bar and tighten socket head screw (ST-1177-32).
(2) Gauge enters on one side and not on opposite slight
2. Install torsion bar (ST-1177-33), threaded end first,
misalignment.
No problem if bar rotates freely.
through bore feed assembly, (ST-1177-17) start threads into
(3) Gauge loose oversize bore.
end hole of torsion bracket (ST-1 177-34). The flats on bar
(4) Gauge enters on front and not on rear of bore tapered
can be used to secure it to bracket.
bore.
3. Locate tapped hole in end of block and secure torsion
6.
Mark bores to be salvaged.
bracket to block with a suitable capscrew and washer.
4. Pull out on plastic knob of feed assembly until pin is
ASSEMBLING MICROMETER TOOL BIT SETTING GAUGE
free of slot and turn one-fourth (1/4) turn, then pull complete
AND TOOL BIT
feed assembly back all the way to the knob and tighten wing
1. Place micrometer base shaft (ST-1177-46) through
setscrew in feed assembly to secure on torsion bar.
bore of micrometer bracket (ST-1177-45) and thread into
5. Install square head set bolt in second threaded hole of
micrometer base (ST-1177-44). Tighten securely.
torsion bracket end and tighten snug against cylinder block to
2. Tighten the socket head screw (ST-1177-29) in the
stabilize torsion assembly.
micrometer .bracket until the bracket is tight on the micrometer
6. Turn plastic knob on drive assembly one-fourth (1/4)
base shaft; micrometer hole in micrometer bracket must be in
turn until pin seats in groove.
alignment with cutting tool hole in micrometer base shaft.
7. Install adapter (ST-1177-31) in other end of boring bar
3. Install centering ring (ST-1177-39) over micrometer
with the 1/2 inch square drive out. Lock with socket head
base shaft and micrometer (ST-1177-43) in micrometer
setscrew.
bracket: a. Adjust micrometer thimble to value stamped on
8. Lock swivel joint (ST-1177-27) in a 1/2 inch drill chuck.
centering ring.
These instructions assume use of a right hand rotation drill.
b. Hold micrometer spindle against centering ring and
9. Install tool bit holder on boring bar, next to journal to
tighten socket head screw in micrometer bracket. Check to
be cut. When operating, boring bar will feed toward feed
see that micrometer spindle turns free.
assembly. Make sure tool bit cutting edge is turned in
4. Remove centering ring and install appropriate cutter
direction of drill rotation.
holder over micrometer shaft.
10. With swivel joint on boring bar adapter, bore the
journal. Keep boring bar well lubricated during all boring
operations.
348
