327 Flashcards
a typical application for a dividing head is the milling of a
gear
the index holes around the spindle of the dividing head are use in __ indexing
direct
if a dividing head has 24 holes around its spindle nose and you must cut four equally spaced notches in a workpiece how far must you rotate the spindle between cut
six holes
if a dividing head has a 40:1 gear ratio how many times must you turn the worm to move the spindle one-quarter of a complete revolution
10
how many crank turns are needed to index each of 12 equally spaced cuts on a workpiece?
3 1/3
suppose indexing a workpiece requires 4 turns of the index crank you will use a hole circle on the index plate with how many holes
20
on a dividing head with a 40:1 ratio one turn of the index crank move the spindle how many degrees
9
for simple angular indexing on a 40:1 dividing head you can use an index plate circle with how many holes
54
compound indexing differs from simple indexing in that you
turn the index plate itself
differential indexing is similar to but more accurate then ___ indexing
compound
what makes a universal dividing head different from a plain dividing head
its spindle nose can be swung 90 degrees
when you use a center on the dividing head spindle to hold a workpiece you install the other center in the
footstock
when mounting work on the dividing head center you assure a positive flow of power from the dividing head spindle to the workpiece by using a
driver and milling machine dog
when using a chuck to hold a workpiece on the dividing head you can give the workpiece extra support with a
steady rest
if you straddle mill a hexagonal workpiece how many times must you position the work
three
why should you insert a cap into the opening of the dividing head spindle
to keep chips out of the spindle
when using the direct indexing method you should not
count the zero hole
to use the plain indexing method the worm and worm gearing in the dividing head must be
engaged
when plain milling which side of a hexagonal workpiece should you mill after taking the first cut?
the opposite side
the dividing head is useful for drilling holes
in a circle
cutting the teeth in a spur gear is a type of ___ milling
form
to mill spur gears you should use ___ cutters
special profile
compute the outside diameter of a 30 tooth spur gear blank with a diametral pitch of six
5.333
which of the following factors does not affect cutter selection for milling spur gears
whole tooth depth
series of eight cutters each have been developed to cut gears with different numbers of teeth
diametral pitch
to index the teeth of a large diameter gear use a
rotary table
when measuring a newly cut gear over pins you should use a
micrometer
to check spur gear tooth thickness at the pitch circle use a
gear tooth vernier caliper
the distance between adjacent helices that are wound on a common cylinder is called the
helix pitch
the lead of a helix is determined by the
milling machine lead
to mill a helix you must use change gears to link the lead screw of the milling machine with the
dividing head worm shaft
if the ratio of change gearing is 1:1 and the lead of the milling machine is 10in a helix milling would have a lead of
10in
how many change gears usually make up a set
four
in the change gear formula 40/40 x 24/60 how many teeth will the two driving gears each have
40 and 24
in order to reverse the direction of a gear rotation so that you can mill either a right or left hand helix use an
idler gear
when using simple angular indexing to mill 15 teeth into a cylindrical workpiece how far apart must you space each tooth
24 degrees
in order to obtain the proper helix angle when milling a helical workpiece you must swivel the
machine table
which of the following factors is not important for you to know about a helical gear you are
where it will be used
when milling helical gear teeth you should not draw the cutter back through the work after a cut is complete because
you could damage the gear tooth surface
the tooth dimensions of spur gears are described by circular pitch what measurement do you use to describe helical teeth gear
normal diameter pitch
what function does a cam perform
they change the direction of motion of machine parts
the follower in a nonpositive cam system would not be controlled by
a groove in the cam
the distance that one cam lobe moves the follower from its the distance that one cam lobe moves the follower from its starting point as the cam rotates is the
cam rise
the total distance that a lobe on a uniform ruse cam would move the follower if the lobe extended a full 360 is the.
cam lead
when milling a plate cam you need a dividing head and a
vertical milling attachment
when milling plate cams the dividing head spindle and the cutter cannot be
in the horizontal plane
when milling a uniform rise cam with a short lead the angle at which you set the vertical milling attachment determines the correct setting for the
dividing head spindle
on which side of the workpiece do you position the cutter when milling a short lead cam
lower
if one lobe of uniform rise cam covers 120 degrees of the circumference and has a rise of.25in what is the cam lead
.75in
when milling nonuniform rise cams you should use
the incremental cut method
