Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
40 Cards in this Set
- Front
- Back
what is the important part of the sewing machine when it comes to classifying it into oscillating and rotary?
|
the rotary hook and oscillation shuttle which is the device that is out of sight in the base of the machine but does the very important job of forming each stitch after the needle has passed thread through the fabric
|
|
what machine has a hook that makes two complete revolutions to complete one stitch
|
rotary sewing machines
|
|
what is the type of stitch commonly used and made by sewing machines in repair work?
|
the lockstitch
|
|
what are the four basic parts of the stadard sewing machine?
|
the bed uprise arm and face
|
|
what is housed in the Bed of the standard sewing machine?
|
the linkage from the safety clutch pulley to the sewing hook assembly
|
|
what is housed ini the uprise of the standard sewing machine?
|
the arm shaft connestion belt
|
|
what is the balance wheel connected to in the standard sewing machine?
|
the arm shaft in the arm which operates the needle bar mechanism in the face of the machine
|
|
what powers the standard sewing machine?
|
an electric motor which is connected to the motor driving pulley by a clutch
|
|
how do you connect the motor to the clutch?
|
it is connected by pressing the forward part of the foot treadle.
|
|
what is the aft part of the treadle?
|
the brake which acts upon the clutch
|
|
how is the pressure of the presser foot on the material released?
|
either by a knee lifter or a hand lifter.
|
|
how can the presser foot be raised?
|
it can be raised by pushing the knee lifter to the right.
|
|
where is the hand lifter located?
|
behind the face of the machine
|
|
how may the presser foot be lifted and locked into position
|
it can be lifted and locked into position by raising the hand lifter to its highest position
|
|
what are the two most commonly used oscillation sewing machine?
|
it is an oscillation sewing machine that has a recommended speed of 2200 stitches perminute and makes a lockstitch it is bery good for sewing nylon cloth and can be used for sewing light weight canvas up to 8 ounces and the number of stitches can be regulated from 7 to 32 stitches per inch
|
|
what is the reason that sewing machines need oiling?
|
they need oiling to ensure easy operation and to prevent unnecessary wear of the moving parts
|
|
how often should a machine be oiled when in constant use?
|
twice a day a new machine should be oiled more frequently
|
|
what type of oil is recommended for oiling 31-15 sewing machines?
|
a 10w mineral oil
|
|
what are the two distinct timing operations for the 31-15 machine?
|
one operation times the needle with the shuttle the other timing operation times the feed dog with the needle.
|
|
what does it mean if a class 31 sewing machine does not form the lockstitch if it skips stitches or if it frays or breaks thread?
|
the needle is not moving in the proper relationship with the shuttles motion.
|
|
what action do you take when using a class 31 sewing machine if the needlle is not moving in the proper relationship with the shuttles motion
|
first make sure you have the right needle check the needle for the correct class variety 16 by 87 and size insert the needle in the needle bar long groove to the left as far as it will go and next compare the needle stroke to the shuttle stroke
|
|
what is the feed driving eccentric?
|
an adjectaable connection between the arm shaft the shaft in the head and then feed rock shaft first shaft beneath the bed of the machine.
|
|
what should be the position of the feed dog if the feed mechanism is properly timed when the point of the needle reaches the material?
|
it should be on its downstoke and level with the throat plate.
|
|
what does the height at which the feed dog should be set depend on?
|
the weight and number of plies of the material being sewn if the feed dog is set too low the material does not feed through the machine and if the set is to high it may cut or fray the material
|
|
what is the recommended height of the feed dog for sewing lightweight canopy material?
|
it is slightly less than one tooth above the throat plate.
|
|
what can happen if the thread take up spring is not adusted properly ?
|
a loop can form over the needle hole in the throat plate and the needle can split the thread as it enters the needle hole
|
|
how should the thread take up spring be set?
|
it should be set so that the spring will have completed its downward motion and be resting on the stop when the needle on its downstroke reaches the fabric
|
|
what is the purpose of the grooves on machine needles?
|
the purpose is to allow the thread to fall back into the needle when it enters the material to prevent the thread from breaking or fraying
|
|
what determines the selection of the correct size needle?
|
the size and type of thread and material used
|
|
what will be the range of the sizes of the class 16 by 87 needles used for most sewing?
|
size 18 through size 22
|
|
what is the size 18 needle used for
|
sewing two to four plies of thin material such as silk nylon or rayon with size E thread
|
|
what is the size 20 needle used for?
|
sewing five or more plies
|
|
what is the size 21 needle used for?
|
sewing two to four plies of medium weight materials such as aircraft cloth 12 ounce duck light leather and artificial leather.
|
|
what size needle is used for sewing two to four pleies of medium weight material such as heavy duck lightweight and medium weight webbing and russet leather?
|
size 22
|
|
what size needle is used for sewing elastic or rubberized materials
|
size 24
|
|
how may you check the condition of a needle?
|
slide a fingernail over the point. if it scratches or catches the nail the needle should be replaced with a new one
|
|
how may a dull needle be sharpened?
|
it may be sharpened by placing it in the chuck of a drill press, and the drill operated at high speed while holding a fine frain sharpening stone lightly against the side of the needle at the proper angle the point is then polished with a piece of russet leather.
|
|
what should be done before attempting to remove the bobbin case?
|
turn the balance wheel toward you until the needle moves upward to its highest position
|
|
what is the procedure to follow to remove the bobbin case?
|
first remove the slide in the bed of the machine so you can see what you are doing then reach under the table with your left hand and using your thumb and forefinger open the bobin case latch and lift out the bobbin case
|
|
while winding the bobbin what should you make certain if there is no material under the presser foot?
|
the presser foot is raised and is not riding on the feed dog.
|