Evening star., 1921-11-13

Answers TO Last Weeks Questions.

! Answers to Last Weeks Questions.
l. Constant grinding or grating of
transmission gears whether the car
is in gear and in motion or standing
/ idle with engine running must be
caused by misalignment of the gears,
considerable wear or by a chip Of
metal. gear tooth or other foreign
object in the transmission case aud
lodged. presumably. at the end of the
case where the gear teeth are rub
bing against it while revolving. If
; the latter Is the cause of the noise
| the loose piece of steel must be in
| contact with either the main drive
shaft gear or one of the counter
! irrespective OF what gears are
fmeshed. and also revolve with gears
| in neutral and car idle If clutch is
engaged and engine running.
2. Sparkling of the commutator of
| Il generator may indicate wear of the
brushes, but more often it indicates
! that the brushes are loose or that
/ there is vibration in the generator
drive. The former trouble is usually
| caused by the springs of the brush
; holders being loose and the latter by
driving gears not in balance or their
shaft sprung. Again. the generator
may not be mounted properly.
.. Governors are used on truck and
| tractor engines to regulate engine
and vehicle speed. The governor can
he set at n certain speed and sealed,
after which the vehicle or the engine
cannot exceed that speed. This is
regarded as necessary for heavy
freight carrying trucks and slow
speed tractors when to go beyond a
trrix- oil
greatly increased wear to the vehicle
and to the roads.
4. Case-hardened steel is soft steel
with only it's outer surface hardened
The process consists of placing the
parts to be hardened in an iron tube
large enough to hold them without
touching. or with any Of the parts
touching each other. Into this tube
and around the parts is packed a
composition of charcoal. salt and
herosene-soaked sawdust. This is
called the hardening compound, and
after being packed in the tube the
open ends of the latter are sealed
with fire clay. The tube and its con-
tents are then placed in a forge fire.
heated to bright red and allowed
to remain in the fire for two hours
more or less. according to how deep
the hardening is required. also ac-
ccrding to the size of the pieces
treated Greater strength is acquired
If after hardening. each piece is
again heated to a bright red. dipped
in oil. then heated to ii dull red and
again plunged in oil. Finer grained
material viii result. Thin case har-
dening is something done by heating
the part red. sprinkling with potas-
SUM cyanide. allowing it to remain
heated for a few minutes and then
iinmersing the part in oil or. water.
5. Changing gears from low to sec
ond speed on a hill is probably re-
garded quite task hy the novice or
driver unfamiliar with his machine.
Such a. person invariably attempts to
shift the gears as he would on leve
road-bv simply speeding up the car
and engine enough in low gear to get
the car in motion. When. he attempts
this on a hill he finds that before the
shift is made and clutch is let in the
car speed has dropped to poin'
when it is impossible to get undc-
way by opening the thrott!e--the en-
gine stalls. To make the shift cor
ractly without strain on the engine
and drive syStsr, tn. speed must b.
accelerated considerably more-tyice
as fast on good-siz-d hill as would
be required on level road. When this
speed is attained depress the clutch
pedal enough to free the engine shif,
the gears without seconds pause
let up the clutch pedal ard while it is
coming UP again accelerate the en-
gine. The throttle should be opened