Looper arm does not clamp over bobbin case all the time

the needle / hook timing has to be exact for the thread to be picked up
turn the hand knob on the end until the needle is at the bottom of the movement and is just about to start coming up
The hook of the bobbin case should almost be at the eye of the needle
The bobbin case hook is not adjustable as it is fixed on the drive shaft but the arm that drives the needle shaft is clamped on the shaft so by loosening off that clamp the needle and be moved to correct position
under normal sewing operations including broken needles , that timing seldom alters much so if it is way out then suspect a belt drive problem between the upper drive shaft and the bobbin drive shaft
It is normally a toothed drive belt that may have jumped a tooth in which case a trip to a service center would be in order

if you look closely at the components of the machine they should have small marks on them that line up with each other or marks on the case. most sewing machines are timed this way the marks have to be lined up on both arms and that should work.

hi larry.
not sure if this link will help,but go to this link and scroll down the page and you should see a service manual.plus you might see something on the page that might help you out.

Singer 457 thread hanging on bobbin case between bobbin case and clamp...

If the upper thread is not intercepting the bobbin thread, first try a brand new needle. Verify that it is installed correctly--the flat side is facing the correct direction.

If it still doesn't pick up the bobbin thread, it most likely has a timing issue, ie the needle is arriving at the wrong time to meet the bobbin thread. Take it for service or search the internet for multiple web sites and videos discussing sewing machine timing.

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the eye of the needle has to be at or marginally below the hook of the bobbin case
on the up stroke of the needle so that the hook can pick up the needle thread and run it around the case
at the end of the machine there is a straight shaft that the needle arm is attached to and the clamp for the arm has a screw that can be loosen so that the position of the needle can be set in relation to the hook
singer have good pdf down load workshop manuals that explain it with diagrams

Did you remove the plate covering bobbin and clean out any thread and lint bits that might be catching and causing the problem? Also take out the bobbin case and see if there is any thread nesting there. Be sure you get that case in just right or it won't spin properly and loop top and bottom threads together. I sew a lot of fleece and textured fabrics so my motto s always, " when in doubt, clean it out". Works 99+++% of the time.

Try taking the bobbin case out and re-insert. It sounds like the case that holds the bobbin is not inserted correctly. You might also try checking to be sure that the needle is inserted properly. Sometimes the needle gets loose and drops down too low. unscrew, push the needle up as far as it will go, then tighten the screw.

Replacing the bobbin case after changing the thread spool gets you back to sewing. The Singer Simple model is designed for the beginning sewer. Even with its simplistic design, often getting started takes a bit of time, concentration and practice. Without the bobbin casing properly in place, the machine will not sew. You can get the machine up and running again.

The little spool holds the thread inside the bobbin casing.
The little spool holds the thread inside the bobbin casing.

Turn off the power to the machine. Power is not needed for any part of the process. Turn the machine off and unplug for safety reasons.

Turn the hand crank on the machine to move the needle into the highest position. Move the presser foot the up position.


Open the hinged latch covering the front of the bobbin cover. This is the device that holds the spool in place.

Place the threaded spool inside the inner casing. Place in so the thread is running in a clockwise direction.

Slide the thread through the slot opening on the let bottom of the casing. The slot is next to the outer arm of the casing. Close the hinged latch.


Hold the casing so the outer arm is sticking straight up. The thread will be coming out to the left of the arm; lay it under the arm to the right.

Push the casing into the internal bobbin slot on the machine. It will lightly snap into place.

Replace the outer machine cover over the bobbin

You will find that it was most likely the top looper has moved to the left too far, undo the looper clamp and press the looper to the right by about 3mm. Then turn the machine over to see if it still hits anything, when the top looper comes up past the bottom looper there should be about 0.5mm clearance between the two. Try this first please.
Also the arm shaft may have moved. Trace the shaft back to where there is a clamp type crank with usually a hexagon head clamp screw. Loosen this and set the top looper so as the eye of it is just past the needle when it is all the way up and to the left.
You are correct in not using the machine under power, turn by hand when you think it is correct and make sure there is nothing hitting.

Insert the bobbin case without a bobbin to see if it will go all the way into the locked position. If it does,the bobbin case and basket are okay.
Check inside the bobbin basket(where the bobbin goes) and see if there is thread or lint wrapped around the spindle the bobbin case sits on. If there is, remove it. If there isn't ,then the bobbin is probably sprung and needs to be replaced.
sewman7