How do I get the teeth to grab and advance the material on my very old Bernina 830?
Well there's a number of reasons why it may not be advancing the material. First, ensure that the teeth are completely cleaned-out - get an old toothbrush, or similar with firm filaments and, with the stitch-plate removed and the bobbin door open, give the teeth a really firm clean across the teeth to remove anything in between ... this is especially important if you've been sewing with metallised fabric or thread. If the teeth are nice and clean, check if they are still pyramidal with a reasonably 'sharp' point facing backwards - if the machine is very old and very well used, the teeth might be rather rounded and it may be time that you have a new feed dog fitted ... some of the old machines are difficult to obtain spares, but they're mostly still out there. Most commonly, check how far the teeth of the feed dogs protrude above the stitch plate ... this is a bit difficult to do and should really be done with a proper gauge, but generally they should protrude 1mm above the stitch plate - less than that and you wont get the material to move properly, especially if its fine material. Lastly, it could be the foot pressure that's the problem ... if there's inadequate foot pressure, the material will not be pushed adequately onto the dogs. Again, unfortunately, you really need a proper gauge to set the foot pressure, but if the dogs are clean, in reasonable condition and have 1mm of clearance above the stitch plate, you can try increasing the foot pressure a bit. This is done by opening the top cover and you will see a large-ish flat-blade screw in a threaded tube just behind where the needle bar goes up and down and to the left of the takeup arm. If the screw is rather near the top of the threaded tube, you can try screwing it down (clockwise) maybe 2-3 turns to see if it makes a difference ... of not, dont be tempted to just keep screwing up the pressure ... there's something else wrong. Oh .... and by the way .... before you've done any of the above, I assume you've checked that the feed-dogs are not dropped ! You can drop the feed-dogs to do embroidery etc on the 830 - there's a small round knob below the stitch length control - make sure its turned to the position that shows a tooth pattern and not the cross-hathced pattern and make sure the feed dogs do actually come above the stitch plate when turning the handwheel - if they dont, or moving the feed-dog drop control doesn't make any difference, then the link mechanism is almost certainly jammed (really, really common on old machines that haven't been regularly maintained!). To free that off, you need to remove the free-arm cover and look to the front right side of the mechanics - you'll see a linkage that should turn when you rotate the feed-dog drop control - if this doesn't separate or is permanently separated, whatever you do with the control, you need to give it a drop or two of Bernina sewing oil and gently help it move - once free, that should solve the problem. I cant think of any other reasons !!
Hope that helps !
Nov 16, 2011 |
Bernina Sewing Machines