18.  What  is  the  lead  of  the  spiral  that  will  be  cut  on  a
milling  machine  which  has  a  lead  of   10"  when  there  is  a
56-T  gear  on  the  worm,  a  32-T  gear  as  the  first  gear  on  the
stud,  a  48-T  gear  as  the  second  gear  on  the  stud,  and  a
72-T  gear  on  the  feed  screw  ?


122


EEVIEW  PROBLEMS


Exercises.    Tapers

1.  Find  the  T.P.F.  of  taper  A  on  the  automobile  pinion
shaft  shown  in  the  blueprint  on  page  123.
2.  In  Ex.  1  find  the  tailstock  offset  for  cutting  taper  A.
3.  As  in  Ex.  1,  find  the  T.P.F.  of  taper  B.
4.  In  Ex.  3  find  the  tailstock  offset  for  cutting  taper  B.
5.  Find  the  T.P.I,  of  the  gib  key  shown  in  the  blueprint.
In  the  following  table  supply  each  missing  specification  for
2-ball  clamping  levers  of  the  type  shown  in  the  blueprint :


L

i

D

d

T.P.F.
TAILSTOCK  OFFSET

6.
41"

2ft"

1"

ft"

7.
5J

8ft

H

i

8.
<*

m

I

T9<f

9.
7*

*H

if

5
f

10.
8i

5|

it

H

11.  Find  the  T.P.F.  of  the  automobile  connecting  rod.
In  the  following  table  supply  each  missing  specification  for
tap-wrench  shells  of  the  type  shown  in  the  blueprint:


D

d

?

T.P.F.
ANGLE  WITH  Axis

12.
ft"

ft"

M"

13.
1

i   •

1.6"

14.
J

T6

2.5

15.  In  the  tapper  tap  blank  shown  in  the  blueprint,  if
i  =  4£",  f  =  TV;,  £>  =  fV',  and  d  =  0.140",  find  the  T.P.F.
and  the  included  angle  of  the  taper.
